Latest ArticlesWettability transition is a significant responsive mechanism which is widely applied to construct smart materials and systems. The broad-spectrum responsiveness of the wettability transition makes it a promising way to expand innovative applications. Here, we develop a track-guided self-transportation system mediated by sequential wettability transition accompanied with capillary transportation. Alkaline fuel is loaded into polydimethylsiloxane (PDMS) cuboid to trigger the wettability transition of distributed superhydrophobic tracks laid in shallow water. After the wettability transition, the induced capillary force can propel the repetitive track-to-track transportation of PDMS. Importantly, the spacing between adjacent tracks is rationally designed based on multiple factors including threshold of wettability transition, diffusion kinetics and capillary interaction. Furthermore, the track-guided transportation system is applied to realize directed self-assembly of multiple PDMS building blocks for designated configuration, which increases the complexity and intelligence of self-assembly systems.
High efficiency and low-cost catalyst-driven electrocatalytic CO2 reduction to CO production are of great significance for energy storage and development. The severe competitive hydrogen evolution reaction occurs at large negative potential window limits the achievement of the target product from CO2 at high efficiency. Here, we successfully prepared Cux/CdCO3 composite catalyst rich in interfaces, in which achieved high CO Faraday efficiency exceeded 90% in a wide potential window of 700 mV and highest value up to 97.9% at −0.90 V vs. RHE. The excellent performance can be ascribed to the positive contribution of Cux/CdCO3, which maintains a suitable high local pH value during electrochemical reduction, thus inhibiting the competitive hydrogen evolution reaction. Moreover, the compact structure between Cu and CdCO3 ensures fast electron transfer both inside catalysts and interface, thus speeding up the reaction kinetics of CO2 to CO conversion. Theoretically calculations further prove that the combination of Cu and CdCO3 provides the well-defined electronic structure for intermediates adsorption, significantly reducing the reaction barrier for the formation of CO. This work provides new insights into the design of efficient electrochemical CO2 reduction catalysts for inhibiting hydrogen evolution by adjusting the local pH effect.
Electrochemical nitrogen reduction reaction (NRR) is a mild and sustainable method for ammonia synthesis. Therefore, developing high activity, selectivity, and economic efficiency catalysts with considering the synergistic effects between catalysts and carriers to design novel structural models is very important. Considering the non-noble metal NRR catalyst, Mo3, we tried to find a suitable carrier which is stable and economical. Herein, we used the largest atomically precise aluminum-pyrazole ring (AlOC-69) to date (diameter up to 2.3 nm). The larger ring cavities and the presence of abundant hydroxy groups make AlOC-69 an ideal molecular carrier model and provide a basis for studying its structure-activity relationship. The formation energy (−0.76 eV) and stable Mo-O bonds indicate that Mo3 can be stabilized on the Al10O10 surface. Additionally, N2 has fully activated due to the strong interaction between the p-orbital of N and the d-orbital of Mo. The low limiting potential (−0.28 V) emerges that Mo3@Al10O10 has ideal catalytic activity and selectivity. This research provides a promising catalyst model and an understanding of its catalytic process at the atomic level, providing a new approach for the co-design of catalyst and carrier in NRR.
Photosynthesis [6CO2 + 12H2O → (CH2O)6 + 6O2 + 6H2O] in nature contains a light reaction process for oxygen evolution and a dark reaction process for carbon dioxide (CO2) reduction to carbohydrates, which is of great significance for the survival of living matter. Therefore, for simulating photosynthesis, it is desirable to design and fabricate a bifunctional catalyst for promoting photocatalytic water oxidation and CO2 reduction performances. Herein, a molecular confined synthesis strategy is reasonably proposed and applied, that is the bifunctional CoOx/Co/C-T (T = 700, 800 and 900 ℃) photocatalysts prepared by the pyrolysis of molecular Co-EDTA under N2 and air atmosphere in turn. Among the prepared photocatalysts, the CoOx/Co/C-800 shows the best photocatalytic water oxidation activity with an oxygen yield of 51.2%. In addition, for CO2 reduction reaction, the CO evolution rate of 12.6 µmol/h and selectivity of 75% can be achieved over this catalyst. The improved photocatalytic activities are attributed to the rapid electron transfer between the photosensitizer and the catalyst, which is strongly supported by the current density-voltage (j-V), steady-state and time-resolved photoluminescence spectra (PL). Overall, this work provides a reference for the preparation and optimization of photocatalysts with the capacity for water oxidation and CO2 reduction reactions.
A double-cable conjugated polymer DCPIC-BO is designed via introducing a long-branched alkyl chains 2-buthyloctyl into the acceptor side unit. Compared with the double-cable polymer (DCPIC-EH) with the 2-ethylhexyl alkyl chains, the solubility of the DCPIC-BO in non-halogen solvents is substantially improved. Therefore, a power conversion efficiency (PCE) of 9.77% can be obtained by the devices processed from o-xylene at 40 ℃, while the DCPIC-EH cannot be processed due to its poor solubility under this condition. Moreover, PCEs of 10.10% for small-area (0.04 cm2) devices and nearly 9% for devices with an area of 1 cm2 are achieved using a non-halogenated solid additive in o-xylene, realizing the "absolutely halogen-free" OSC fabrication.
Lithium metal batteries (LMBs) are considered to be one of the most promising high-energy-density battery systems. However, their practical application in carbonate electrolytes is hampered by lithium dendrite growth, resulting in short cycle life. Herein, an electrolyte regulation strategy is developed to improve the cyclability of LMBs in carbonate electrolytes by introducing LiNO3 using trimethyl phosphate with a slightly higher donor number compared to NO3− as a solubilizer. This not only allows the formaion of Li+-coordinated NO3− but also achieves the regulation of electrolyte solvation structures, leading to the formation of robust and ion-conductive solid-electrolyte interphase films with inorganic-rich inner and organic-rich outer layers on the Li metal anodes. As a result, high Coulombic efficiency of 99.1% and stable plating/stripping cycling of Li metal anode in Li||Cu cells were realized. Furthermore, excellent performance was also demonstrated in Li||LiNi0.83Co0.11Mn0.06O2 (NCM83) full cells and Cu||NCM83 anode-free cells using high mass-loading cathodes. This work provides a simple interphase engineering strategy through regulating the electrolyte solvation structures for high-energy-density LMBs.
Metal-organic frameworks (MOFs) received considerable attention to adsorption and removal of various environmental pollutants because of some inherent advantages. However, it is challenging but meaningful to design and fabricate hierarchical mixed-dimensional MOFs with synergistic effects to enhance the performance for removal and preconcentration of environmental pollutants. Herein, a new hierarchical two-dimensional (2D)-three-dimensional (3D) mixed-dimensional cactus‐like MOF@MOF hybrid material (PCN-134@Zr-BTB) was prepared by in-situ growth of 2D MOF nanosheets (Zr-BTB) on the surface of 3D MOF (PCN-134). The PCN-134@Zr-BTB composites combine the advantages of 2D and 3D MOFs with extensive mesoporous structures and large surface area for effective removal and enrichment of bisphenols (BPs). In comparison with pristine PCN-134 and Zr-BTB materials, the PCN-134@Zr-BTB hybrid material presented excellent adsorption performance for BPs. The adsorption isotherms are consistent with the Langmuir model, and the maximum adsorption capacity of four bisphenols (BPs) ranged from 135.1 mg/g to 628.9 mg/g. The adsorption kinetics are in accordance with the pseudo-second-order model. The recoveries ranged from 72.8% to 108%. The limits of detection were calculated at 0.02–0.03 ng/mL. The enrichment factors were calculated in the range of 310–374. According to FT-IR and XPS analysis, the main adsorption mechanisms are hydrogen bonding and π-π stacking. Nevertheless, this work provides a new and convenient strategy for the preparation of new hierarchical mixed-dimensional MOF@MOF (PCN-134@Zr-BTB) hybrid material for extraction and enrichment of BPs from aqueous matrix.
Compared with the widespread exploitation of hot electrons in plasmonic nanoparticles (NPs), hot holes generated from plasmonic metal interband transitions, are often overlooked in photoelectrochemistry, including photoelectrochemical sensing. Motivated by the subtle spectral overlap between the characteristic plasmonic bands of Ag NPs and interband transitions of Au, herein, we construct unusual core-shell Ag@Au NPs via an anti-galvanic reaction to promote the generation of hot holes. Benefiting from the unique plasmon resonances of Ag cores in specific wavelength regimes, Ag@Au can excite multiplied hot holes while Au cannot under the same conditions. With satisfactory accuracy and good practicability, the photoelectrochemical sensing platform based on Ag@Au NPs possesses a detection limit of 77 nmol/L for glucose, exhibiting significantly higher sensitivity compared to that using Au NPs. This work exemplifies the applications of interband hot-hole accumulation initiated by plasmons and may inspire more strategies to explore the utilization of hot holes in photoelectrochemistry.
A novel BINOL-based fluorescence probe (S)-6 featuring a sodium sulfonate fragment at the 2′-position was designed and synthesized via simple synthetic procedures under mild reaction conditions. The water-soluble probe (S)-6 displays excellent enantioselective recognition toward 15 common amino acids, and it can be used for enantiomeric excess determination of amino acids. The fluorescence intensity of (S)-6 treated with amino acids reaches the maximum after standing for only 30 min at room temperature and remains stable in the following 5.5 h, which has great potential in the application of chiral fluorescence analysis due to its timeliness and outstanding fluorescent stability.
Electrode materials with strong desalting ability is an important research direction of capacitive deionization. In this study, HKUST-1 was successfully synthesized by the solvothermal method, and MOFs-derived porous carbon/Cu@Cu2O composites were prepared by simple pyrolysis as cathode materials for CDI. After high-temperature pyrolysis, the Cu+ site with unsaturated coordination is generated, and the structure changes from micropores to the coexistence of mesoporous and micropores. The complex pore structure is conducive to strengthening ion migration and diffusion. The results show that the porous carbon/Cu@Cu2O materials derived from MOFs depend on the pseudocapacitance behavior for capacitive deionization and desalination. At a voltage window of -1.2 V~1.2 V, a current density of 40 mA/g, and 5 mmol/L NaCl, the HDC-1100 exhibited the best desalting capacity of 30.9 mg/g. HDC-1100 also has good cycle stability. After 20 cycles of adsorption and desorption, the desalting capacity almost does not decrease. Therefore, MOFs derived porous carbon/Cu@Cu2O composites are expected to be an excellent choice for CDI cathode materials.