Recent advances in carbon-based materials for electrochemical CO<sub>2</sub> reduction reaction

Recent advances in carbon-based materials for electrochemical CO₂ reduction reaction

PDF

Zengqiang Gao¹, Junjun Li¹, Zhicheng Zhang^*, Wenping Hu

Chinese Chemical Letters | 2022, 33(5) : 2270 - 2280

Less

Chinese Chemical Letters | 2022, 33(5): 2270-2280

• Review •

Recent advances in carbon-based materials for electrochemical CO₂ reduction reaction

Full

Zengqiang Gao¹, Junjun Li¹, Zhicheng Zhang^*, Wenping Hu

Affiliations

Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, School of Science & Collaborative Innovation Center of Chemical Science and Engineering, Tianjin University, Tianjin 300072, China

Published: 2022-05-15 doi: 10.1016/j.cclet.2021.09.037

Outline

Abstract

Less

The increase of atmospheric CO₂ concentration has caused many environmental issues. Electrochemical CO₂ reduction reaction (CO₂RR) has been considered as a promising strategy to mitigate these challenges. The electrocatalysts with a low overpotential, high Faradaic efficiency, and excellent selectivity are of great significance for the CO₂RR. Carbon-based materials including metal-free carbon catalysts and metal-based carbon catalysts have shown great potential in the CO₂RR, owing to the tailorable porous structures, abundant natural resources, resistance to acids and bases, high-temperature stability, and environmental friendliness. In this review, various carbon materials including graphene, carbon nanotubes, quantum dots, porous carbon, and MOF-derived catalysts, etc., for the CO₂RR have been summarized. Particularly, recent progress in terms of the mechanism and pathway of CO₂ conversion has been comprehensively reviewed. Finally, the opportunities and challenges of carbon-based electrocatalysts for the CO₂RR are proposed.

Key words

CO₂ reduction / Electrocatalysis / Carbon materials / Chemicals and fuels / Single-atom catalysts

Cite this Article

Zengqiang Gao, Junjun Li, Zhicheng Zhang, Wenping Hu. Recent advances in carbon-based materials for electrochemical CO₂ reduction reaction[J]. Chinese Chemical Letters, 2022 , 33 (5) : 2270 -2280 . DOI: 10.1016/j.cclet.2021.09.037

Full Text

Less

1 Introduction

Less

The fossil fuels supply about 75% of global energy demands, and the CO₂ emissions associated with excessive fossil fuel consumption resulted in global extremes, ocean acidification, and sea-level rise. Currently, the atmospheric CO₂ concentration has increased to 418.94 ppm in 2021 [1]. Converting CO₂ into sustainable fuels and chemical feedstocks, via biochemical, photocatalytic, and electrocatalytic reactions, etc., provides a promising approach to close the carbon cycle and alleviate energy and environmental problems. To date, electrocatalytic CO₂ reduction reaction (CO₂RR) has been considered as an important route to address the above-mentioned issues, because of its moderate conditions, controllable process, minimized chemical consumption, and easy-to-scale-up applications [2-5]. However, CO₂ has a stable molecular structure (high C=O dissociation energy of 803 kJ/mol), leading to a high kinetic barrier [6-8]. During the electrochemical reduction of CO₂, the multi-proton-coupled electron transfer processes usually generate a significant number of intermediates, resulting in low product selectivity. Therefore, the rational design and controlled synthesis of advanced electrocatalysts with high activity, selectivity, and stability are highly desired.

Until now, various electrocatalysts including noble metals, metal alloys, and transition metal oxides have been developed, exhibiting outstanding electrocatalytic performance for the CO₂RR. However, it remains a great challenge to fabricate the electrocatalyst with low cost, highly exposed active sites, and industrial-grade current densities. Up to now, carbon-based materials have been regarded as one of the most promising catalysts for the CO₂RR owing to the inherent advantages, such as abundant natural resources, resistance to acids and bases, high-temperature stability, and environmental friendliness. The tunable electronic structures and excellent electrical conductivity of carbon-based materials are viable to reduce the energy barrier for C-C coupling [9]. Despite the poor catalytic activity of carbon materials, their performance can be greatly improved via doping heteroatoms or constructing metal/carbon composites. More importantly, constructing carbon-based single-atom catalysts or tandem catalysts becomes a potential strategy to achieve a good catalytic activity, selectivity, as well as stability [10, 11]. In this review, we have comprehensively summarized the recent development of metal-free and metal-based carbon materials for the CO₂RR, involving synthetic strategies, catalytic active sites, and reaction mechanisms.

2 The catalytic mechanisms for CO₂ reduction

Less

The complex processes of electrochemical CO₂ reduction yield various reduction products. According to the number of carbon atoms, the reduction products can be classified as C₁ products (e.g., CO and HCOOH), C₂ products (e.g., C₂H₄, C₂H₆ and C₂H₅OH) and C₃ products (e.g., C₃H₆ and C₃H₇OH). The value-added multi-carbon (C₂₊) products are more favored over the C₁ products_. The standard potentials for the conversion of CO₂ into different products are similar (Table 1) and the standard potential for H₂ within this range would decrease the selectivity for high-value products [12-14]. The principle of the CO₂RR contributes to investigate a favorable kinetic pathway to bypass the hurdles of the high overpotential and hinder the process of the HER. The reaction pathways of the CO₂RR are shown in Fig. 1. First, CO₂ is adsorbed on the surface of the catalysts, forming unstable ^*CO₂^δ- radicals which are readily protonated to generate bidentate intermediate (^*OCHO) or adsorption intermediate (^*COOH) [15, 16]. For example, Song et al. found that the formation of ^*COOH and ^*CO are more beneficial on pyridinic N and pyrrolic N than that on graphite N and pure carbon. The energy for the ^*CO-to-^*CHO conversion on pyridinic N sites is 0.82 eV, whereas it is a slight exothermicity of -0.24 eV on pyrrolic N sites, revealing that the formation of ^*CHO is thermodynamically advantageous on pyrrolic N [17]. Furthermore, the metal center with various d-electron structures on metal-based carbon materials exhibited unusual adsorption energies of CO₂-related intermediates via the fine-tuning of crystal facets, and chemical states, which can adsorb CO₂ or the related intermediates [18]. Then, the H⁺ is adsorbed on ^*CO₂^δ− a proton-coupled electron transfer process or hydrogenation towards different products. Significantly, ^*CO intermediates are crucial intermediates to produce multi-carbon products [19]. Since protons can be accepted by C and O, the reaction in this step is divided into two parts by the position of accepted protons: (1) O in ^*CO firstly accepts protons to generate ^*COH and combines with several protons to produce CH₄ by losing one water molecule [20]. (2) The protonated ^*CO generates ^*CHO and finally produces methanol through several subsequent hydrogenation processes [21].

For the reaction path of the C₂ product, the protonated ^*CO attached to another ^*CO produces ^*OCCOH. ^*OCCOH is then further protonated to form ^*OCHCH₂. The intermediate discards the O attached to the active site to generate C₂H₄ or is repeatedly hydrogenated to generate CH₃CH₂OH [22, 23]. After ^*OCCOH discarding one water molecule, the two C atoms are attached to the active sites. Finally, CH₃COCH₃ is formed by hydrogenation and protonation. For generating C₂₊ products, the Cu, the only metal, can convert ^*CO to ^*CHO, ^*COH, or ^*OCCO, due to the suitable ^*CO adsorption energy, whereas Ag, Au, Fe, Ni and Pt own weaker or stronger ^*CO adsorption energy [24]. By constructing metal-based carbon catalysts, the electronic structures of the active center can be regulated by adjusting coordination environments such as the species and numbers of coordination atoms and metal elements [25]. For example, the Ni 3d orbital in N-doped graphene possessed an unpaired electron which could be transferred from Ni(I) to the C 2p orbital of CO₂ through the delocalization effect, forming the

species to reduce the energy barrier for the CO₂RR [26].

3 Carbon-based materials for CO₂RR

Less

3.1 Metal-free carbon materials

Carbon materials with high surface area and electronic conductivity are usually utilized as an effective matrix to load other components. Particularly, porous carbon materials can facilitate the adsorption and reduction of CO₂, as well as the rapid penetration of electrolytes due to the well-developed porosity and rich specific surface chemistry. Therefore, the structural configurations for carbon frameworks have significant influences on catalytic performance [27-29]. However, most of the metal-free carbon catalysts are electrochemically inert due to the negligible ability to activate CO₂. Thus, various strategies for the preparation of nanoporous heteroatom-doped carbon materials (e.g., chemical doping and post-treatment) have been developed for the CO₂RR. For example, the incorporation of heteroatom (e.g., B, N or S) can efficiently improve the electrochemical activity, because of the electronic properties effectively modulated by heteroatom doping. The tunable porous structure can increase the local CO₂ concentration through the nanoconfinement effect. The change of electronic properties arising from heteroatom doping is favorable to optimizing charge-carrier concentration, offering numerous catalytic active sites and promoting C-C coupling reactions. More importantly, the catalytic performance of carbon-based materials could be precisely tailored by the active sites within the carbon matrix.

Kumar et al. reported that the N-doping carbon nanofibers (NCNFs) showed about 13 times higher current density than Ag bulk for CO₂-to-CO conversion by using ionic liquids (ILs, 1-ethyl-3-methylimidazolium tetrafluoroborate) as the electrolyte (Figs. 2A and B) [30]. The ILs enabled CO₂ to form an intermediate complex (EMIM-CO₂) and thus promote the FE_CO, endowing NCNFs with good stability (Fig. 2C). The unchanged N 1s X-ray photoelectron spectroscopy (XPS) spectrum before and after the CO₂RR test indicated that positively charged carbon atoms were the active site rather than doping nitrogen. The redistribution of the charge and spin density of oxidized carbon atoms after doping nitrogen improved the catalytic activity of the NCNFs.

Given their unique electronic and geometric features, nitrogen-doped carbon nanotubes (NCNTs) were also employed for CO₂-to-CO conversion, showing a low overpotential of -0.18 V_RHE and selectivity of 80% [31]. The catalytic activity of NCNTs synthesized by the liquid chemical vapor deposition method was mainly attributed to pyridinic N which had a lone pair of electrons to bind CO₂, followed by pyrrolic and graphitic N (Figs. 3A and B). The onset potential of the pyridinic N site was -0.30 V_RHE, lower than that of Cu (−0.31 V_RHE), Au (−0.63 V_RHE) and Ag (−0.79 V_RHE), which resulted in the current density of NCNTs four times that of CNTs.

The hierarchically structured porous N-doped carbon/CNT composite membrane (HNCM/CNT) was further developed and displayed high activity, selectivity, and stability for formate with a FE of 81% (Fig. 3C) [32]. The increased pyridinic N defects in the HNCM/CNT catalyst contributed to the improvement of catalytic performance towards CO₂RR, because the basic carbon atom adjacent to the pyridinic N is prone to adsorb CO₂. Xu et al. further tailored nitrogen contents by adjusting the ratio of nitrogen species and the optimized catalysts showed a good selectivity of 90% for CO₂-to-CO conversion and stability of over 60 h [33]. Density functional theory (DFT) calculations illustrated that the radical anion intermediate (

) can be stabilized by N defects to lower the reduction barriers.

Compared with CNTs, graphene without interference factors (e.g., curvature effects or the number of walls) can be used as a more suitable platform for an independent study of catalytic activity on different N-defect structures within the carbon network. The pyridinic N among the N-doping defects could endow adjacent carbon atoms with a positive charge. For example, N-doped graphene (NG) as a robust electrocatalyst could convert CO₂ into formate with a FE of 73% in aqueous electrolyte [34], while N-doped 3D graphene foam (NGF) displayed a good electrocatalytic performance for CO₂-to-CO conversion, rather than formate [35]. Specifically, NGF showed comparable activity with a FE_CO of 85% at a lower overpotential of 0.47 V, compared to Au and Ag. DFT calculations confirmed that the free energy barrier could significantly decrease after adding N atoms in graphene owing to triple-pyridinic N strongly binding intermediate COOH^* (Figs. 3D and E).

Considering the porous structure and chemical diversity on the surface, the nanoporous carbon (NPC) materials are also excellent electrocatalysts for the CO₂RR. Yang et al. reported that the structure of carbon nanofiber membranes can be tuned by co-doping N and S and constructing hierarchical pores [36]. The as-synthesized membranes with excellent flexible and free-standing properties exhibited a FE_CO of 94% at a current density of 103 mA/cm². Besides, Se-doped carbon nanosheets (Se-CNs) with different sizes of the porous structure were also designed for the CO₂RR [37]. Impressively, Se-CNs with the optimized active sites, high surface area, and hierarchical pores, were able to promote penetration, transport, and the reaction of the reactants, and thus the partial current density of CO for Se-CNs was over 11 times that of CNs. Through edge-Se-C-N-configurations obtained by XPS and extended X-ray absorption fine structure (EXAFS) analysis, Se-CNs catalyst exhibited a smaller free energy barrier (0.32 eV) than that of CNs (0.63 eV), the proper adjustment of electronic structures made the electronic state of the active site more suitable for bonding CO₂ rather than adsorbing hydrogen. Accordingly, Se-CNs displayed better selectivity of CO (90%).

Fluorine-doped carbon (FC) by pyrolyzing commercial BP2000 with a fluorine source can also achieve a highly selective CO₂-to-CO conversion with a FE of 89.6% and a small Tafel slope of 81 mV/dec [38]. DFT calculations revealed that C4 and C9 located on the metal position of FC possessed the low Gibbs free energy barrier, conducive to COOH^* adsorption (Figs. 4A–C). Furthermore, Kuang et al. applied a second doping process to increase the density of pyridinic N and defects after pyrolysis of ZIF-8, achieving a good FE_CO of 92% [39]. Subsequently, Pan et al. achieving N, P-co-doping mesoporous carbon (N, P-mC) by annealing phytic-acid-functionalized ZIF-8 in NH₃ and the obtained materials achieved selectivity close to 100% (Fig. 4D) [40].

N-Doped carbon can effectively enhance the activity of quantum dots towards CO₂RR [41, 42]. For example, Ajayan and co-workers reported that N-doped graphene quantum dots (NGQDs) with an abundant density of N-doping defects could be prepared by exfoliating N-doped graphene oxide (GO) (Fig. 5A) [43]. Interestingly, different species could be regulated by potential on NGQDs, ranging from single-carbon to multi-carbon products. Local density of states and thermodynamic free energy of intermediate states further confirmed that N-doped GQD and CNT showed a much larger energy gain compared to NG, contributing to binding ^*COOH to achieve a high catalytic activity (Fig. 5B). Owing to the easy, inexpensive and large quantity production and earth-abundance, graphene-like carbon nitride (g-C₃N₄) with abundant pyridinic nitrogen species is a promising candidate for heterogeneous catalysis [44]. Lu et al. constructed graphitic carbon nitride onto multiwall carbon nanotubes (g-C₃N₄/MWCNTs) by treating the precursor (dicyandiamide and MWCNT) in a H₂SO₄ and HNO₃ mixture (3:1, v/v) and polycondensation, and the g-C₃N₄/MWCNTs with covalent attachment achieved a maximum FE_CO of 60% and prominent stability of 60 h [45]. This work revealed that the electronic structures of g-C₃N₄ can be effectively modified by metal-free carbon materials. Subsequently, Zhi et al. reported that g-C₃N₄/doped graphene materials could significantly boost CO₂ reduction via the interfacial electron transfer [46]. With the assistance of computational methods, the impact of heteroatom doping (X = B, N, O, P) was comprehensively explored. The observed variable adsorption energetics and electronic structures, among different doping cases, indicated that the interfacial electron transfer modulation can promote the catalytic performance for producing methane.

In addition to conventional CNT and graphene structures, diamond nanocrystals with unique tetrahedral bonding units can facilitate C-C coupling. Although the electrical conductivity of pristine diamonds is poor, it can be substantially promoted by doping. Through microwave plasma-enhanced chemical vapor deposition, Liu et al. deposited N-doped nanodiamond (NDD) on Si rod array substrates, achieving a high FE of 77.6% towards CH₃COOH and improving the selectivity for C₂₊ products (Figs. 6A–C) [47]. Afterward, the same group further applied a hot filament chemical vapor deposition method to achieve B and N element co-doped nanodiamond (BND) [48]. The obtained materials can achieve a FE of 93.2% towards C₂H₅OH (Fig. 6D), owing to the synergistic effect between B and N on BND.

3.2 Metal-based carbon materials

Anchoring metal on carbon composite is an ideal strategy for large-scale production. The synergistic effect between metals and carbon materials contributed to improving catalytic activity and selectivity towards specific products, where the metal elements (Au, Pd, Ag, Fe, Co, Ni, Cu, In, etc.) can efficiently adsorb and activate CO₂ to lower the energy barrier, and carbon materials with the high surface areas and tunable porous structure supply a large electrochemical active area to decrease the diffusion resistance [49-53]. As known, Cu is regarded as the fundamental metal for electrocatalytically converting CO₂ into multi-carbon products. The strong defect sites within carbon-supported Cu catalysts can stabilize related intermediates and alter the selectivity of the catalyst for specific products. Generally, HOCCH^* is a key intermediate that determines whether the product is ethylene or ethanol. Gangeri et al. investigated the conversion of CO₂ into various oxygenates by coating Fe or Pt onto CNT (Fe/CNT or Pt/CNT) [54]. Although Fe/CNT exhibited better catalytic activity than Pt/CNT, the faster deactivation occurred on Fe/CNT due to the cross-over of the electrolyte, particularly K ions. It was found that FeO_x compounds were produced on the CNTs after reaction. Furthermore, Wang et al. investigated the confinement effect using amorphous N-doped carbon/Cu (N-C/Cu) to improve the selectivity for C₂H₅OH (52% ± 1%) [55]. The capping layers (N-C) possessed a strong electron-donating ability, which can effectively promote C-C coupling and suppress the deoxygenation process to achieve an enhanced selectivity for ethanol. Zhong et al. also constructed Fe and N doped porous carbon nematosphere (FeNPCN) for the CO₂-to-CO conversion, exhibiting a high FE_CO of 94% [56]. 3D hierarchical FeNPCN was prepared by carbonizing FeO-PDA formed by the polymerization of dopamine triggered by Fe species. The addition of the Fe atom can effectively promote the formation of the intermediates because Fe-N coordination is conducive to the formation of the COOH^* intermediate. Moreover, the composition of the syngas, i.e., the ratio of CO and H₂, could be efficiently adjusted. Similarly, Sun et al. integrated bismuth and bismuth oxide nanoparticles (NPs) on nitrogen-doped reduced graphene oxide nanosheets (Bi/Bi₂O₃/NrGO) by combining the hydrothermal method and calcination [57]. The strong synergistic effect between Bi and Bi₂O₃ together with the undercoordinated sites efficiently improved the catalytic performance, which achieved a FE of 85% for formate with a low Tafel slope of 166 mV/dec. Besides, Du et al. integrated CoO on N-doped mesoporous carbon and carbon nanotubes (MC-CNT/Co) for reducing CO₂ to CH₃CHO and C₂H₅OH [58]. The pyrrolic-N and pyridinic-N on MC-CNT can significantly promote the C-C coupling and stabilize ^*CO generated by CoO, which is favorable to forming C₂H₅OH. Superior to other N-containing carbon substrates, the g-C₃N₄ with abundant pyridinic nitrogen atoms can efficiently contact with oxygen-bound intermediates (^*OCH_x, ^*O and ^*OH) thanks to high affinity, contributing to the deep reduction of CO₂. For example, the g-C₃N₄ as a molecular scaffold can appropriately modify the electronic structure of Cu, which could optimize some key reaction intermediates (Figs. 7A and B) [59]. Interestingly, Cu-C₃N₄ with the strong adsorption of CO contributed to the lower free energy level for the intermediates (Figs. 7C and D). Thus, the Cu-C₃N₄ surface can greatly benefit the activation of CO₂, leading to a more facile reaction to desirable products, compared to the Cu(111) surface and other Cu complexes on nitrogen-doped carbons. Afterward, g-C₃N₄ supported Au NPs was synthesized by Zhang et al., achieving a FE_CO of over 90% in a wide range of potential from −0.45 V_RHE to –0.85 V_RHE [60]. Impressively, the negatively charged Au surface induced by the interaction of two compounds could stabilize the key intermediate ^*COOH to enhance the CO₂RR performance, further confirmed by the DFT. (Figs. 7E-G).

To date, the engineering of defect, interface, strain, lateral size and thickness, and heteroatom doping have been considered as effective approaches to improve the catalytic activity of 2D materials [61, 62]. Interestingly, downsizing the metal NPs to single-atom level, single-atom catalysts (SACs) with unique electronic structure, low-coordinated metal atoms, strong metal-support interactions, and maximum atom utilization can integrate the advantages of both homogeneous and heterogeneous catalysts [63-66]. SACs with isolated metal atoms dispersed on conductive support have shown excellent catalytic performance and thus become a research hot in the field of catalysis [67-69]. Combining atomically dispersed metal sites and the coordinated atoms can greatly boost the catalytic performance towards CO₂RR by facilitating the activation or the dissociation of the intermediates [70-73]. More importantly, the fabrication of SACs contributes to systematically understanding the underlying relationship between material structure and properties at atomic level [74]. Physical adsorption, polymerization, chemical bonding, or integration in frameworks endowed complexes with well-defined metal-N_x (M-N_x) sites. SACs with M-N₄ sites as the efficient electrocatalysts for the CO₂RR were confirmed by DFT calculations [75-80]. To obtain heterogeneous catalysts with atomically dispersed metal sites, a common method is to pyrolyze metal precursors using appropriate nitrogen and carbon sources [81]. In 2015, Strasser et al. prepared N-doped porous carbon black (N-C) containing different metals by repeated heat treatments and acid-leaching processes [82]. They found that the N-C catalyst presented a similar selectivity to the N-doped carbon catalysts with M-N₄ moieties. More importantly, the metal sites could further reduce the adsorbed CO to hydrocarbons. Through a topo-chemical, catalyst with an exclusive Ni-N₄−C structure can accelerate charge transfer and lower free energy to form ^*COOH [83]. Atomic Fe dispersed on N-doped graphene catalysts with Fe-N₄ moieties showed a high FE_CO of over 90% in a flow cell reactor at low overpotential due to the high CO₂ adsorption and CO desorption of discrete Fe³⁺ ions coordinated with pyrrolic N atoms [84]. In 2020, Zhang and co-workers applied a feasible strategy to synthesize the In single-atom catalyst (In-SAs/NC) with exclusive isolated In-N₄ atomic interface sites for generating formate [85]. By combining a wet-impregnation process and pyrolysis process, the main group of indium catalysts can be accurately regulated at the atomic scale. Therefore, catalyst displayed a large turnover frequency (TOF) of 12, 500 h⁻¹ at 0.95 V_RHE, and the FE for formate and current density could reach 96%, 8.87 mA/cm², respectively.

The coordinated N ligands act as a crucial role in improving the catalytic performance of SACs towards CO₂RR. The surface-active sites can effectively suppress mass transfer and improve the atom economy. The supported Ni metal NPs can be transformed to thermal stable Ni single atoms that were mostly located on the surface of pyrolysis-treated ZIF-8 as the support, through thermal atomization (SE-Ni SAs@PNC) (Fig. 8A) [86]. When Ni nanoparticles contacted with N-doped carbon with abundant defects, this synthetic process not only transformed the Ni NPs into single atoms owing to the strong coordination and the continuous loss of atomic Ni species, but also created numerous pores to facilitate the contact of dissolved CO₂ and single Ni sites. Moreover, carbon substrate can stabilize the surface of atomization of Ni NPs. The contrast experiment that Ni NPs dispersed on the non-defective XC-72 matrix without any aggregation occurred the migration and aggregation of Ni atoms after a pyrolysis treatment revealed that the defective NC is a crucial factor for the formation of the SAs. Compared to pyridinic N-coordinated Ni (Ni-4N), pyrrolic N-coordinated Ni (Ni-3N) possessed lower free energy for ^*COOH intermediate. Pyrrolic N-coordinated atomically dispersed metal ions also presented more outstanding activity and stability than pyridinic N-coordinated catalysts (Figs. 8B and C). Besides, anchoring atomically dispersed Co-N₅ structure on polymer-derived hollow N-doped porous carbon spheres was also designed to implement a robust CO₂RR [87]. The X-ray absorption near-edge structure (XANES) and EXAFS revealed that a single Co atom possessed a positive charge and the valence of the Co element in the obtained catalyst was slightly higher than that of CoPc. Interestingly, the Co-N₅ sites were the active center and played a crucial role in the rapid formation of COOH^* intermediate and the desorption of CO.

Strasser et al. designed a series of M-N-C via an impregnation process and subsequent heat treatments (Fig. 9A) [88]. Specifically, the obtained Ni-N-C catalyst exhibited better catalytic performance, followed by Fe-N-C catalyst (Figs. 9B and C). This result was further confirmed by Li et al. (Figs. 9D and E) [78]. The ultrathin graphene-like Ni-N-C catalysts via pace-confinement-assisted molecular-level complexing approach achieved the highest FE_CO of 96% and the TOF of 1060 h⁻¹ at a moderate overpotential, compared to other M-N-C catalysts (M = Mn, Co, Fe, Cu, etc.). Besides, Pan et al. confined low-valent Ni-based NPs within nitrogen-doped carbon (Ni-NC) catalyst for the CO₂RR, exhibiting a maximum FE_CO of 98% [89]. Interestingly, Ke and co-workers synthesized a highly active manganese N-heterocyclic carbene pincer complex ([MnCNCOMe]BF₄) [90]. The strong electron-donating ability of the -OMe group and electronic tuning by para substitutions are favorable to the conversion of CO₂ into CO.

Metal-organic frameworks (MOFs) are porous hybrid materials consisting of metal nodes and organic ligands [91-94]. The active sites within a particular metal-ligand periodic interval of MOFs are in a state of monoatomic dispersion. Pristine MOFs can be used as electrocatalyst precursors or templates to fabricate MOF-derived porous carbon nanomaterials with superior conductivity and stability. Inspired by electrocatalytic degradation of carbon tetrachloride by Co-porphyrinic MOF [95], Kubiak's group applied electrophoretic deposition to construct a heterogeneous system by integrating redox-conductive Fe-porphyrins into thin MOF-525 films, which electrochemically covered catalytic sites (~10¹⁵ sites/cm²) in conductive surface [96]. The active Fe(0)-porphyrin species in Fe-based MOF films can produce 15.3 µmol/cm² of CO and 14.9 µmol/cm² of H₂, whose current density can reach 2.3 mA/cm² within 0.5 h, and turnover number (TON) for CO in controlled potential electrolysis (CPE) was 272. With an acidic proton donor (trifluoroethanol, TFE), the TON of Fe(0)-porphyrin system reached 1520. Moreover, the current density and stability were up to 5.9 mA/cm² and 3.2 h, respectively, better than that without TFE.

Whereafter, Albo et al. further investigated the electrocatalytic reduction of CO₂ by using MOFs (HKUST-1, CuAdeAce) and metal-organic aerogels (CuDTA, CuZnDTA) [97]. By cyclic voltammograms (CV), HKUST-1 showed the best current density after five scans among the above-mentioned four materials, indicating an excellent performance in transferring electrons. The HKUST-1 with a surface area of 1710 m²/g exhibited maximum yield rates of 5.62 × 10⁻⁶ and 5.28 × 10⁻⁶ molm⁻² s⁻¹ for CH₃OH and C₂H₅OH, respectively. Because the charge can be transported within MOF films by either linker or electron/hole redox hopping. 3D porphyrin-based MOF-525 catalyst synthesized by dip-coating method admirably converted CO₂ into CO with low overpotential, achieving a maximum FE_CO of 91% and a TOF of 0.336 site⁻¹ s⁻¹ after 10 h electrolysis [98]. Liu et al. applied epitaxially-grown molecular (ReL(CO)₃Cl) to surface-grafted MOF catalyst, and monolithic coatings obtained current densities exceed 2 mA/cm² with a FE_CO of 93% [99]. Due to the porosity and conformance of the inherited catalytic active sites after carbonization, MOF was a potential candidate in the field of non-noble metal catalysts. Zhao et al. synthesized OD Cu/C catalysts by the pyrolysis of HKUST-1 to convert CO₂ into ethanol [100]. The carbon matrix can protect Cu from deactivation and improve the efficient transfer of CO₂ and diffusion of the products to the solutions. The synergetic effect of the highly dispersed Cu and C matrix rendered the production rate for the methanol and ethanol up to 12.4 and 13.4 mg L⁻¹ h⁻¹, respectively, with a total FE of 71.2% at −0.3 V_RHE. In addition, the metal-metal interface plays an important role in improving the activity and selectivity of the catalysts. Three heterometallic HKUST-1 dopped ions (Zn, Ru, Pd) reported by Albo et al. were also applied to investigate the catalytic performance towards CO₂RR [101]. Ru(Ⅲ)-electrocatalyst showed the highest yield of alcohol (47.2%).

Wu's group prepared nitrogen-doped porous carbon by ZIF-assisted strategy and ionic exchange, where Ni ions were utilized to replace Zn within the cavities of ZIF-8 (Ni SAs/N-C) (Fig. 10A) [102]. Due to the improved adsorption energy towards CO and electronic conductivity, the electron can rapidly shift from the electrode to the absorbed CO₂ to form a radical intermediate. Thus, the Ni SAs/N-C displayed a FE_CO of over 71.9% with a prominent TOF of 5273 h⁻¹ and the current density can reach 10.48 mA/cm² (Figs. 10B and C). Based on the gas diffusion electrode (GDE), Li's group applied Cu₃(BTC)₂ to capture CO₂ for synthesizing hydrocarbons, in which capture capacity reached up to 1.8 mmol/g [103]. Under relatively negative potentials, the FE of CH₄ for Cu₃(BTC)₂ can double without the addition of Cu₃(BTC)₂. While for the competitive HER, the FE of H₂ was declined to 30%.

Yang et al. employed a multi-step pyrolysis approach to fabricate atomically dispersed transition metals (Ni, Co, NiCo, CoFe and NiPt) on N-CNTs (NiSA-N-CNTs) for the CO₂-to-CO conversion [104]. The obtained materials were subsequently characterized by aberration-corrected scanning transmission electron microscopy and X-ray absorption spectroscopy (XAS) to explore the coordination structures. While pyridinic N and graphitic N kept the same in ex situ XANES spectroscopy, Ni L-edge peak revealed higher photon energy, revealing that Ni-N species were the active centers for the CO₂RR. The NiSA-N-CNTs can achieve a high FE_CO of 91.3% and a TOF of 11.7 s⁻¹. It has been confirmed that the Ni-N₄−C structure can exhibit excellent catalytic activity towards the CO₂RR. Recently, low-coordination single-atom Ni electrocatalysts (Ni-N₃−C) were obtained via a facile post-synthetic metal substitution (PSMS) strategy [105]. After the pyrolysis of the Zn-MOF, acid treatment and decoration, abundant Ni-N₃ sites were formed (Fig. 11A). Importantly, Ni-N₃−C catalyst showed better catalytic performance than Ni-N₄−C and N−C owing to the favorable kinetics. This result was also confirmed by XPS spectrum, synchrotron-based XAS measurement and Fourier transforms (FT) extended X-ray absorption fine structure. Ni-N₃−C catalyst with a high TOF of 1425 h⁻¹ can be used in the Zn-CO₂ battery, showing a discharge potential of 0.41 V (Fig. 11B). Moreover, integrating MOF with the function of support for electrochemical CO₂-to-CO conversion is an intriguing strategy, which is capable of tailoring active molecular in the porous network to maximize active sites. The charge transport could be controlled by the morphology of MOF. Yaghi et al. incorporated the active molecule (TCPP-Co) into an Al-based MOF (Fig. 11C) [106]. They found that all of the active sites in homogeneous catalysts (porphyrin molecular) can contact the electrolyte, electrons and their transfer can be changed by adjusting the morphology and thickness of MOF. The selectivity for CO was over 76% at −0.7 V_RHE, running for over 7 h.

Further, a NC/MOF hybrid comprising Ag NCs thin film (Ag@Al-PMOF) was constructed to improve the performance towards CO₂RR and suppress HER [107]. The change of the interface between the NPs and the MOFs can not only change the electronic structure of Ag but also contribute to suppressing HER and promoting the CO₂RR, compared to the bare Ag NC counterparts. In 2019, Zhang and co-workers fabricated exclusive Bi-N₄ sites on porous N-doped carbon networks (Bi SAs/NC) through thermal decomposition of the Bi-MOF and dicyandiamide (DCD) [108]. The synthesized complex achieved high activity for CO₂-to-CO conversion with a high FE_CO of 97% and a TOF of 5535 h⁻¹. Compared with the Bi clusters or nanoparticles, the Bi atoms achieved a higher FE of CO. It is worth noting that Bi is regarded as the material for generating formate, while BiN₄/C with a low free energy barrier is conducive to the formation of CO.

Owing to the intrinsically electrically insulated property, pristine MOFs have been rarely studied in electrocatalysis. Recently, the electrical conductive MOFs have been constructed via through-bond approach, extended conjugation approach, through-space approach, guest-promoted approach, and so on [109, 110]. The enhanced electrical conductivity can endow MOFs with excellent catalytic performance and provide a new pathway to boost the development of the CO₂RR. For example, 2D Cu-based conductive MOF (copper tetrahydroxyquinone, Cu-THQ) was constructed for the CO₂RR and achieved a FE_CO of 91% at a high current density of 173 mA/cm², which are more active than other reported MOFs-based catalysts [111, 112]. The HRTEM images illustrated that Cu-THQ displayed a honeycomb arrangement with the AB stacking model (Fig. 12A). The operando Cu K-edge X-ray absorption near-edge spectroscopy and DFT calculations revealed the existence of reduced Cu (Cu⁺) and Cu-THQ with the CO adsorption free energies was favorable to converting CO₂ into CO (Fig. 12B). Meanwhile, 2D Cu-THQ with high atomic utilization and easy surface modification contributed to the improvement of performance [113]. Sargent et al. systematically incorporated Ag NPs in face-centered cubic MOFs which was changed by modifying both the organic linker (1, 4-benzene dicarboxylic acid, BDC, and 1, 4-naphthalenedicarboxylic acid, NDC) and the metal node (Zr and Y), improving the FE_CO from 74% to 94% (Fig. 12C) [114]. The advanced technologies can contribute to the deep investigation of the mechanism reaction. In this work, XAS and in situ Raman spectroscopy confirmed that the surface of Ag NPs in stable MOFs can effectively optimize the ^*CO binding mode by increasing local CO₂ concentration, achieving CO_atop/CO_bridge control, rather than conventionally controlling the binding energy.

To avoid the energy penalty, tandem catalysis has been considered as an efficient strategy to generate high-value products (C₂₊) [115]. For example, Sargent et al. integrated FeTPP[Cl] (5,10,15,20-tetraphenyl-21H,23H-porphine iron(Ⅲ) chloride) on a sputtered Cu electrode (FeTPP[Cl]/Cu) to investigate the molecule-metal interfaces [116]. FeTPP[Cl] sites showed excellent catalytic activity for ^*CO, leading to the increased concentration of CO near the Cu surface, which can lower reaction energy for ^*CHCHOH to steer selectivity from C₂H₄ to C₂H₆OH (41%).

Formate is an important chemical raw material, and many researchers focus on improving the performance of Bi-based, In-based, and Sn-based catalysts for the conversion of CO₂ into formate. Bi-based catalysts are regarded as the most commercially available materials for producing formate [117]. In 2020, Zhu et al. firstly obtained atomically thin bismuthene (Bi-ene) by in situ electrochemically transforming Bi-based metal-organic layers (Fig. 13A) [118]. Interestingly, in situ attenuated total reflection-infrared spectroscopy (in situ ATR-IR) indicated that the adsorbed HCO₃⁻ groups participated in the first proton-couple electron transfer process during the CO₂RR, which was consistent with the analysis of the Tafel test and DFT. The obtained Bi-ene in a flow cell reactor can achieve nearly full conversion for formate in a wider potential range and different electrolytes (Fig. 13B). Furthermore, Bi(1, 3, 5-tris(4-carboxyphenyl)benzene) (Bi(btb)) as the precatalyst underwent a structural rearrangement upon electrocatalysis to produce Bi crystalline, achieving a FE of 95% towards formate [119]. Similar results were also reported in previous literature 120-123. Relying on the Bi element, these reports achieved a high FE for the formate, but the structure change of Bi-based MOFs during the reaction process remains unclear.

In 2021, Qiao et al. monitored and controlled the reconstruction of a Bi-based MOF during the electrochemical CO₂ reduction (Fig. 13C) [124]. They found that Bi-based MOF was firstly converted into Bi₂O₂CO₃ in electrolyte and then Bi₂O₂CO₃ was mediated to Bi by applying potential. Bi catalysts after intentionally reconstructed exhibited high activity, excellent selectivity, and long-term durability for generating formate. This work indicates the significant impact of pre-catalyst reconstruction during the reaction and provides a pathway for the rational design of highly active and stable electrocatalysts.

4 Conclusions and perspective

Less

The electrochemical reduction of CO₂ has been considered as one of the most promising approaches to close the carbon cycle, solve environmental issues and meet energy demands. Until now, various carbon-based catalysts including graphene, carbon nanotubes, quantum dots, porous carbon, and MOF-based catalysts have been fabricated, exhibiting good FEs and selectivity towards the CO₂RR. Due to the tailorable porous structures, abundant resources, and excellent catalytic properties, carbon-based materials are efficient in the reduction of CO₂ to the value-added carbon products. The relevant experiments have been completed, as shown in Table 2. Concerning metal-based carbon catalysts, improving the utilization efficiency of metal atoms is of essential significance for reducing the catalyst cost and promoting sustainability. Through a combination of experiment and theory, precisely controlling the structure of metal-based carbon composite catalysts provides an enormous opportunity for investigating the relationship between structure and performance.

Despite these promising achievements, the catalytic performance still needs to be improved especially in terms of current densities, FE, and selectivity. The catalytic performance of carbon-based catalysts depends on the surrounding environment, active sites, and physicochemical properties. Besides, the multiple electron pathways of the CO₂RR (even more than 18-electron) would generate various related intermediates which can provide many arrangements for protonation, leading to the complexity of the product and uncontrollable process. Furthermore, more efforts are needed to further direct a deeper understanding of the catalytic process to find the optimal catalyst and reaction conditions. Therefore, for the in-depth understanding of possible pathways for the key intermediates and structure-activity relationships, various advanced in situ characterization technologies, such as operando XAS, in situ Raman spectroscopy, electron paramagnetic resonance, in situ surface-enhanced infrared absorption spectroscopy, in situ ATR-IR, and in situ XPS should be further developed and adopted to detect electrochemical reaction or monitor the change of surface state and atomic structure. An electrocatalytic microdevice of the CO₂RR like the chip should also be constructed to directly probe dynamic changes of the catalyst or electrochemical processes.

Identifying the specific role of each component involved in multiple carbon-based composites towards the CO₂RR is a great challenge. In this regard, some new measures or approaches should be further taken to achieve this goal. For example, fabricating conductive MOF via doping, ligands decoration, is a proper strategy for improving the performance of carbon-based catalysts. In addition, fabricating carbon-based tandem catalysts as models for target products, especially Cu-based carbon catalysts, deserves further exploration. Differently, the mass transfer of CO₂ also plays an important role in improving the current density. Some approaches can be utilized to overcome this problem in an aqueous solution: (1) performing this reaction in an organic solvent such as acetonitrile to promote the solubility of CO₂; (2) adjusting reaction systems, such as increasing reaction pressure to promote the solubility of CO₂; (3) designing new electrochemical cells, such as flow cell, overcoming the inherently low diffusion between CO₂ and the catalyst surface.

This review provides the guidance to explore promising strategies for the CO₂RR, so as to achieve high energy efficiency, industry-compatible current densities, and admirable conversion efficiency in the future. Inspiringly, carbon-based materials are expected to achieve the high performance towards the CO₂RR by combining the theory of computer science and quantum chemistry with experiments, which can significantly decrease the workload of researchers.

Declaration of competing interest

Less

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgments

Less

This work was supported by the National Natural Science Foundation of China (No. 22071172), the Strategic Priority Research Program of the Chinese Academy of Sciences (No. XDB12030300), the Ministry of Science and Technology of China (Nos. 2017YFA0204503 and 2018YFA0703200).

References

Less

[1]

CDATA[E. Dlugokencky, P. Tans, NOAA/ESRL, http://www.esrl.noaa.gov/gmd/ccgg/trends/, accessed: July 2021.

[2]

F.P.G. De Arquer, C.T. Dinh, A. Ozden, et al., Science 367 (2020) 661-666.

[3]

Y.S. Wu, Z. Jiang, X. Lu, Y.Y. Liang, H.L. Wang, Nature 575 (2019) 639-642.

[4]

C.H. Yang, S.Y. Li, Z.C. Zhang, et al., Small 16 (2020) 2001847.

[5]

N. Wang, R.K. Miao, G. Lee, et al., SmartMat 2 (2021) 12-16.

[6]

H. Zhong, M. Ghorbani-Asl, K.H. Ly, et al., Nat. Commun. 11 (2020) 1-10.

[7]

J.D. Yi, R. Xie, Z.L. Xie, et al., Angew. Chem. Int. Ed. 59 (2020) 23641-23648.

[8]

O.S. Bushuyev, P. De Luna, C.T. Dinh, et al., Joule 2 (2018) 825-832.

[9]

W.L. Zhu, R. Michalsky, O.N. Metin, et al., J. Am. Chem. Soc. 135 (2013) 16833-16836.

[10]

D.F. Gao, T.F. Liu, G.X. Wang, X.H. Bao, ACS Energy Lett. 6 (2021) 713-727.

[11]

Y.T. Zhu, X.Y. Cui, H.L. Liu, et al., Nano Res. 14 (2021) 4471-4486.

[12]

L. Fan, C. Xia, F.Q. Yang, et al., Sci. Adv. 6 (2020) eaay3111.

[13]

C.H. Yang, F. Nosheen, Z.C. Zhang, Rare Met. 40 (2021) 1412-1430.

[14]

C. Xia, Y. Zhou, C. He, et al., Small Sci. 1 (2021) 2100010.

[15]

L.M. Wang, W.L. Chen, D.D. Zhang, et al., Chem. Soc. Rev. 48 (2019) 5310-5349.

[16]

J.T. Feaster, C. Shi, E.R. Cave, et al., ACS Catal. 7 (2017) 4822-4827.

[17]

Y. Song, S. Wang, W. Chen, et al., ChemSusChem 13 (2020) 293-297.

[18]

K. Zhao, X. Quan, ACS Catal. 11 (2021) 2076-2097.

[19]

T. Chen, T.Y. Liu, X.Y. Shen, et al., Sci. China Mater. 64 (2021) 2997-3006.

[20]

L. Fu, R. Wang, C. Zhao, et al., Chem. Eng. J. 414 (2021) 128857.

[21]

T. Cheng, H. Xiao, W.A. Goddard, Proc. Natl. Acad. Sci. 114 (2017) 1795-1800.

[22]

Y.J. Zhao, L.L. Zheng, D. Jiang, et al., Small 17 (2021) 2006590.

[23]

I. Ledezma-Yanez, E.P. Gallent, M.T. Koper, F. Calle-Vallejo, Catal. Today 262 (2016) 90-94.

[24]

N. Han, P. Ding, L. He, Y. Li, Y. Li, Adv. Energy Mater. 10 (2020) 2070046.

[25]

H. Xu, D. Cheng, D. Cao, X.C. Zeng, Nat. Catal. 1 (2018) 339-348.

[26]

H.B. Yang, S.F. Hung, S. Liu, et al., Nat. Energy 3 (2018) 140-147.

[27]

H.W. Hu, J.H. Xin, H. Hu, X.W. Wang, Y. Kong, Appl. Catal. A: Gen. 492 (2015) 1-9.

[28]

D.S. Su, S. Perathoner, G. Centi, Chem. Rev. 113 (2013) 5782-5816.

[29]

K. Jiang, S. Siahrostami, A.J. Akey, et al., Chem 3 (2017) 950-960.

[30]

B. Kumar, M. Asadi, D. Pisasale, et al., Nat. Commun. 4 (2013) 2819.

[31]

J. Wu, R.M. Yadav, M. Liu, et al., ACS Nano 9 (2015) 5364-5371.

[32]

H. Wang, J. Jia, P.F. Song, et al., Angew. Chem. Int. Ed. 56 (2017) 7847-7852.

[33]

J.Y. Xu, Y.H. Kan, R. Huang, et al., ChemSusChem 9 (2016) 1085-1089.

[34]

H.X. Wang, Y.B. Chen, X.L. Hou, C.Y. Ma, T.W. Tan, Green Chem. 18 (2016) 3250-3256.

[35]

J.J. Wu, M.J. Liu, P.P. Sharma, et al., Nano Lett. 16 (2016) 466-470.

[36]

H.P. Yang, Y. Wu, Q. Lin, et al., Angew. Chem. Int. Ed. 57 (2018) 15476-15480.

[37]

B.X. Zhang, J.L. Zhang, F.Y. Zhang, et al., Adv. Funct. Mater. 30 (2020) 1906194.

[38]

J.F. Xie, X.T. Zhao, M.X. Wu, et al., Angew. Chem. Int. Ed. 57 (2018) 9640-9644.

[39]

M. Kuang, A.X. Guan, Z.X. Gu, et al., Nano Res. 12 (2019) 2324-2329.

[40]

B.B. Pan, X.R. Zhu, Y.L. Wu, et al., Adv. Sci. 7 (2020) 2001002.

[41]

J.J. Wu, S.C. Ma, J. Sun, et al., Nat. Commun. 7 (2016) 13869.

[42]

P.P. Sharma, J.J. Wu, R.M. Yadav, et al., Angew. Chem. Int. Ed. 54 (2015) 13701-13705.

[43]

X.L. Zou, M.J. Liu, J.J. Wu, et al., ACS Catal. 7 (2017) 6245-6250.

[44]

L.M. Azofra, D.R. MacFarlane, C.H. Sun, Phys. Chem. Chem. Phys. 18 (2016) 18507-18514.

[45]

X.Y. Lu, T.H. Tan, Y.H. Ng, R. Amal, Chem. Eur. J. 22 (2016) 11991-11996.

[46]

X. Zhi, Y. Jiao, Y. Zheng, S.Z. Qiao, Small 15 (2019) 1804224.

[47]

Y.M. Liu, S. Chen, X. Quan, H.T. Yu, J. Am. Chem. Soc. 137 (2015) 11631-11636.

[48]

Y.M. Liu, Y.J. Zhang, K. Cheng, et al., Angew. Chem. 129 (2017) 15813-15817.

[49]

O.A. Baturina, Q. Lu, M.A. Padilla, et al., ACS Catal. 4 (2014) 3682-3695.

[50]

R. Daiyan, W.H. Saputera, H. Masood, et al., Adv. Energy Mater. 10 (2020) 1902106.

[51]

Y.Q. Su, H.T. Xu, J.J. Wang, et al., Nano Res. 12 (2019) 625-630.

[52]

M. Zhu, L. Zhang, S. Liu, et al., Chin. Chem. Lett. 31 (2020) 1961-1965.

[53]

C.H. Yang, Z.Q. Gao, W. Dingjia, et al., Sci. China Mater. 65 (2022) 155-162.

[54]

M. Gangeri, S. Perathoner, S. Caudo, et al., Catal. Today 143 (2009) 57-63.

[55]

X. Wang, Z.Y. Wang, F.P. García de Arquer, et al., Nat. Energy 5 (2020) 478-486.

[56]

H. Zhong, F. Meng, Q. Zhang, K. Liu, X. Zhang, Nano Res. 12 (2019) 2318-2323.

[57]

J.J. Sun, W.Z. Zheng, S.L. Lyu, et al., Chin. Chem. Lett. 31 (2020) 1415-1421.

[58]

J. Du, S.P. Li, S.L. Liu, et al., Chem. Sci. 11 (2020) 5098-5104.

[59]

Y. Jiao, Y. Zheng, P. Chen, M. Jaroniec, S.Z. Qiao, J. Am. Chem. Soc. 139 (2017) 18093-18100.

[60]

L. Zhang, F.X. Mao, L.R. Zheng, et al., ACS Catal. 8 (2018) 11035-11041.

[61]

Q. Xu, J. Zhang, D. Wang, Y. Li, Chin. Chem. Lett. 32 (2021) 3771-3781.

[62]

N. Zhang, X. Zhang, L. Tao, et al., Angew. Chem. Int. Ed. 60 (2021) 6170-6176.

[63]

A.Q. Wang, J. Li, T. Zhang, Nat. Rev. Chem. 2 (2018) 65-81.

[64]

Y. Shang, X. Xu, B. Gao, S. Wang, X. Duan, Chem. Soc. Rev. 50 (2021) 5281-5322.

[65]

L. Gong, H. Yang, H. Wang, et al., Nano Res. 14 (2021) 4528-4533. https://link.springer.com/article/10.1007/s12274-021-3366-3.

[66]

X.F. Yang, A.Q. Wang, B.T. Qiao, et al., Acc. Chem. Res. 46 (2013) 1740-1748.

[67]

Y.J. Chen, S.F. Ji, C. Chen, et al., Joule 2 (2018) 1242-1264.

[68]

B.T. Qiao, A.Q. Wang, X.F. Yang, et al., Nat. Chem. 3 (2011) 634-641.

[69]

S. Meshitsuka, M. Ichikawa, K. Tamaru, J. Chem. Soc. Chem. Commun. (1974) 158-159.

[70]

X. Yan, D.L. Liu, H.H. Cao, et al., Small Methods 3 (2019) 1800501.

[71]

F.P. Pan, H.G. Zhang, K.X. Liu, et al., ACS Catal. 8 (2018) 3116-3122.

[72]

D.W. Stephan, Acc. Chem. Res. 48 (2015) 306-316.

[73]

Y.D. Li, Sci. China Mater. 59 (2016) 1.

[74]

J. Yang, W. Li, D. Wang, Y. Li, Small Struct. 2 (2021) 2000051.

[75]

Z.X. Wang, J.X. Zhao, Q.H. Cai, Phys. Chem. Chem. Phys. 19 (2017) 23113-23121.

[76]

A. Bagger, W. Ju, A.S. Varela, P. Strasser, J. Rossmeisl, Catal. Today 288 (2017) 74-78.

[77]

V. Tripkovic, M. Vanin, M. Karamad, et al., J. Phys. Chem. C 117 (2013) 9187-9195.

[78]

F.P. Pan, W. Deng, C. Justiniano, Y. Li, Appl. Catal. B: Environ. 226 (2018) 463-472.

[79]

H.L. Liu, Y.T. Zhu, J.M. Ma, Z.C. Zhang, W.P. Hu, Adv. Funct. Mater. 30 (2020) 1910534.

[80]

W. Yang, Y. Zhu, J. Li, et al., Chin. Chem. Lett. 32 (2021) 286-290.

[81]

G. Wan, G.H. Zhang, X.M. Lin, Adv. Mater. 32 (2020) 1905548.

[82]

A.S. Varela, N. Ranjbar Sahraie, J. Steinberg, et al., Angew. Chem. Int. Ed. 54 (2015) 10758-10762.

[83]

X.G. Li, W.T. Bi, M.L. Chen, et al., J. Am. Chem. Soc. 139 (2017) 14889-14892.

[84]

J. Gu, C.S. Hsu, L.C. Bai, H.M. Chen, X.L. Hu, Science 364 (2019) 1091-1094.

[85]

H. Shang, T. Wang, J. Pei, et al., Angew. Chem. Int. Ed. 59 (2020) 22465-22469.

[86]

J. Yang, Z.Y. Qiu, C.M. Zhao, et al., Angew. Chem. Int. Ed. 57 (2018) 14095-14100.

[87]

Y. Pan, R. Lin, Y. Chen, S. Liu, et al., J. Am. Chem. Soc. 140 (2018) 4218-4221.

[88]

W. Ju, A. Bagger, G.P. Hao, et al., Nat. Commun. 8 (2017) 944.

[89]

K. Xu, S. Zheng, Y. Li, et al., Chin. Chem. Lett. 33 (2022) 424-427.

[90]

C. Huang, J.H. Liu, H.H. Huang, X.F. Xu, Z.F. Ke, Chin. Chem. Lett. 33 (2022) 262-265.

[91]

H. Furukawa, K.E. Cordova, M. O'Keeffe, O.M. Yaghi, Science 341 (2013) 1230444.

[92]

N. Stock, S. Biswas, Chem. Rev. 112 (2012) 933-969.

[93]

M.Y. Gao, B.Q. Song, D. Sensharma, M.J. Zaworotko, SmartMat 2 (2021) 38-55.

[94]

H.B. Meng, Y. Han, C.H. Zhou, et al., Small Methods 4 (2020) 2000396.

[95]

S.R. Ahrenholtz, C.C. Epley, A.J. Morris, J. Am. Chem. Soc. 136 (2014) 2464-2472.

[96]

I. Hod, M.D. Sampson, P. Deria, et al., ACS Catal. 5 (2015) 6302-6309.

[97]

J. Albo, D. Vallejo, G. Beobide, et al., ChemSusChem 10 (2017) 1100-1109.

[98]

B.X. Dong, S.L. Qian, F.Y. Bu, et al., ACS Appl. Energy Mater. 1 (2018) 4662-4669.

[99]

L. Ye, J.X. Liu, Y. Gao, et al., J. Mater. Chem. A 4 (2016) 15320-15326.

[100]

K. Zhao, Y.M. Liu, X. Quan, S. Chen, H.T. Yu, ACS Appl. Mater. Interfaces 9 (2017) 5302-5311.

[101]

M. Perfecto-Irigaray, J. Albo, G. Beobide, et al., RSC Adv. 8 (2018) 21092-21099.

[102]

C.M. Zhao, Dai X. Y, T. Yao, et al., J. Am. Chem. Soc. 139 (2017) 8078-8081.

[103]

Y.L. Qiu, H.X. Zhong, T.T. Zhang, et al., ACS Appl. Mater. Interfaces 10 (2018) 2480-2489.

[104]

Y. Cheng, S.Y. Zhao, B. Johannessen, et al., Adv. Mater. 30 (2018) 1706287.

[105]

Y. Zhang, L. Jiao, W.J. Yang, C.F. Xie, H.L. Jiang, Angew. Chem. Int. Ed. 60 (2021) 7607-7611.

[106]

N. Kornienko, Y.B. Zhao, C.S. Kley, et al., J. Am. Chem. Soc. 137 (2015) 14129-14135.

[107]

Y.T. Guntern, J.R. Pankhurst, J. Vávra, et al., Angew. Chem. Int. Ed. 58 (2019) 12632-12639.

[108]

E.H. Zhang, T. Wang, K. Yu, et al., J. Am. Chem. Soc. 141 (2019) 16569-16573.

[109]

L.S. Xie, G. Skorupskii, M. Dincă, Chem. Rev. 120 (2020) 8536-8580.

[110]

Z.Q. Gao, C.Y. Wang, J.J. Li, et al., Acta Phys. Chim. Sin. 37 (2021) 2010025-2010020.

[111]

L. Majidi, A. Ahmadiparidari, N. Shan, et al., Adv. Mater. 33 (2021) 2004393.

[112]

L. Dai, Q. Qin, P. Wang, et al., Sci. Adv. 3 (2017) e1701069.

[113]

W. Fang, L. Huang, S. Zaman, et al., Chem. Res. Chin. Univ. 36 (2020) 611-621.

[114]

D.H. Nam, O. Shekhah, G. Lee, et al., J. Am. Chem. Soc. 142 (2020) 21513-21521.

[115]

N. Wang, K.L. Yao, A. Vomiero, Y. Wang, H. Liang, SmartMat 2 (2021) 423-425.

[116]

F.W. Li, Y.C. Li, Z.Y. Wang, et al., Nat. Catal. 3 (2020) 75-82.

[117]

Y.H. Wang, W.J. Jiang, W. Yao, et al., Rare Met. 40 (2021) 2327-2353.

[118]

C.S. Cao, D.D. Ma, J.F. Gu, et al., Angew. Chem. Int. Ed. 59 (2020) 15014-15020.

[119]

P. Lamagni, M. Miola, J. Catalano, et al., Adv. Funct. Mater. 30 (2020) 1910408.

[120]

X.R. Zhang, Y.X. Zhang, Q.Q. Li, et al., J. Mater. Chem. A 8 (2020) 9776-9787.

[121]

Z. Yang, H. Wang, X. Fei, et al., Appl. Catal. B: Environ. (2021) 120571.

[122]

X.H. Zhao, Q.S. Chen, D.H. Zhuo, et al., Electrochim. Acta 367 (2021) 137478.

[123]

S.G. Han, D.D. Ma, Q.L. Zhu, Small Methods 5 (2021) 2100102.

[124]

D.Z. Yao, C. Tang, A. Vasileff, et al., Angew. Chem. Int. Ed. 60 (2021) 18178-18184.

Appendix

Less

Year 2022 volume 33 Issue 5

PDF

Cite this Article

BibTeX

Article Info

doi: 10.1016/j.cclet.2021.09.037

Receive Date：2021-08-10
Online Date：2025-12-19
Published：2022-05-15

Article Data

Affiliations

History

Received：2021-08-10
Revised：2021-09-04
Accepted：2021-09-09

Affiliations

References

Share

https://castjournals.cast.org.cn/joweb/ccl/EN/10.1016/j.cclet.2021.09.037

Share to

Scan QR to access full text

Cite this article

BibTeX

Citations

表12种不同金属材料的力学参数

科 Family	属数 Number of genus	种数 Number of species	占总种数比例 Percentage of total species (%)	属 Genus	种数 Number of species	占总种数比例 Percentage of total species (%)
鹅膏菌科Amanitaceae	2	11	5.26	鹅膏菌属 Amanita	10	4.78
小菇科 Mycenaceae	2	12	5.74	丝盖伞属 Inocybe	5	2.39
多孔菌科 Polyporaceae	8	14	6.70	蜡蘑属 Laccaria	5	2.39
红菇科 Russulaceae	3	23	11.00	小皮伞属 Marasmius	6	2.87
				小菇属 Mycena	11	5.26
				光柄菇属 Pluteus	5	2.39
				红菇属 Russula	17	8.13
				栓菌属 Trametes	5	2.39

关闭全屏

BibTeX
EndNote
RefWorks
TxT

Fig. 2 (A) Cyclic voltammetry (CV) of C-film and CNFs in Ar or CO₂. (B) The current density of different materials. (C) Scheme of mechanism for CO₂-to-CO conversion over NCNFs. Reproduced with permission [30]. Copyright 2013, Nature.

Fig. 3 (A) Schematic illustration of N configuration. (B) XPS spectrum of N 1s for NCNTs. Reproduced with permission [31]. Copyright 2015, American Chemical Society. (C) The fabrication process of HNCM/CNT [32]. Copyright 2017, Wiley-VCH. (D) Free energy diagram of the CO₂RR on NG. (E) Schematic illustration of N configuration to reduce CO₂. Reproduced with permission [35]. Copyright 2017, American Chemical Society.

Fig. 4 (A) The different view of the DFT model for FC. (B) Free energy diagram of the CO₂RR to CO on FC and pristine C (with graphene model). (C) Schematic of the pathway on FC. Reproduced with permission [38]. Copyright 2018, Wiley-VCH. (D) Fabrication scheme of N, P-mC. Reproduced with permission [39]. Copyright 2021, Wiley-VCH.

Fig. 5 (A) TEM (TOP) and high-resolution TEM for N-doped carbon-based materials. (B) FE of different products and the current density of NGQDs. Reproduced with permission [43]. Copyright 2017, American Chemical Society.

Fig. 6 (A) Scheme of fabrication of NDD/Si rod array. (B) FE of different products. (C) The reaction pathways for NDD/Si rod array. Reproduced with permission [47]. Copyright 2015, American Chemical Society. (D) FE for the different percentages of N in NDD materials. Reproduced with permission [48]. Copyright 2017, Wiley-VCH.

Fig. 7 (A) The reaction pathways for Cu-C₃N₄. (B) The main reaction intermediates for producing CH₃CH₂OH on Cu-C₃N₄. The electron density for CO adsorbed on (C) Cu-C₃N₄ and (D) Cu-NC. Reproduced with permission [59]. Copyright 2017, American Chemical Society. Au8 cluster adsorbed on C₃N₄ (E) at the hollow site and (F) at the graphene-carbon support. (G) The Gibbs free-energy diagram for /C₃N₄. Reproduced with permission [60]. Copyright 2018, American Chemical Society.

Fig. 8 (A) The scheme of the transformation of Ni NPs into Ni SAs. (B) Adsorption energies of the Ni active site. (C) Free-energy diagram for the CO₂-to-CO conversion. Reproduced with permission [86]. Copyright 2018, Wiley-VCH.

Fig. 9 (A) Materials model and a schematic local structure. (B) FE_CO of different catalysts. (C) Catalyst mass-normalized CO partial currents of different catalysts. Reproduced with permission [87]. Copyright 2017, Springer Nature. (D) FE_CO of different structures. (E) Catalyst mass-normalized CO partial currents of different structures. Reproduced with permission [78]. Copyright 2018, Elsevier.

Fig. 11 (A) Scheme of fabrication of Ni-N3–C catalyst. (B) The scheme of Zn-CO₂ battery using Ni-N₃^–C as cathode catalyst. Reprinted with permission [101]. Copyright 2021, Wiley-VCH. (C) The scheme of TCPP-Co with Al-based MOF for the CO₂RR. Reprinted with permission [106]. Copyright 2017, American Chemical Society.

Fig. 12 (A) HRTEM and Fourier transform of Cu-THQ. (B) The free energies of CuTHQ. Reproduced with permission [111]. Copyright 2021, Wiley-VCH. (C) The synthesized design strategies of MOF. Reproduced with permission [114]. Copyright 2021, American Chemical Society.

Fig. 13 (A) The scheme of synthesis of Bi-ene. (B) Illustration of the self-designed flow cell. Reprinted with permission [118]. Copyright 2020, Wiley-VCH. C) Diagram of reconstruction of Bi-MOF. Reprinted with permission [124]. Copyright 2021, Wiley-VCH.

Articles: Latest Articles; Most Read; Collections

Updates: Events; News; Multimedia

About: About Us

Contact

No. 86 Xueyuan South Road, Haidian District, Beijing

100081

010-62199257

qkjq@cast.org.cn

Copyright © 2025 China Association for Science and Technology. All rights reserved. For all open access content, the relevant licensing terms apply.
Sponsored by the Office of the Leading Group for Cybersecurity and Informatization of CAST, and supported by Science and Technology Review Publishing House