Latest ArticlesAqueous zinc-ion batteries are highly favored for their enhanced safety and reduced cost. However, there exist challenges including zinc dendrite, hydrogen evolution, and surface corrosion to be solved. Using electrolyte additives is a highly convenient approach to solving zinc anode-related issues. Inspired by industrial corrosion protection, a trace amount of the corrosion inhibitor urotropine (URT) is used as an electrolyte additive to protect the zinc anode. Theoretical calculation and experimental analysis confirm the adsorption of URT molecules onto the surface of Zn, which inhibits hydrogen evolution. This adsorption further leads to the formation of an inorganic-organic bilayer solid electrolyte interface (SEI) on the surface of the zinc anode, effectively protecting the Zn anode from corrosion, hydrogen evolution and zinc dendrites. The presence of SEI enables symmetrical Zn//Zn cells to exhibit a long cycling performance of 1750 h at 1 mA/cm2 and an average coulombic efficiency of 99.0% at 1 mA/cm2 in Zn//Cu cells. After being coupled with polyaniline (PANI), the Zn//PANI full battery displays excellent cycle stability and specific capacity.
Density functional theory (DFT) was performed to systematically study the adsorption and dissociation of N2 on Ir(100) and Ir(110) surfaces. By analyzing the properties, including adsorption energies, reaction barriers, and optimal adsorption sites, the hollow (H) sites were finally identified as favorable dissociation sites for N2. The dissociation barriers of N2 are 0.87 eV on Ir(100) and 1.12 eV on Ir(110), which can be overcome at around 348 and 448 K, respectively. Therefore, Ir(100) is screened as a promising catalyst for N2 dissociation compared to Ir(110). This can be attributed to the significantly higher adsorption energy of N2 on the H site of Ir(100) (−0.48 eV) compared to that on Ir(110) (−0.22 eV), leading to different dissociation mechanisms on Ir(100) and Ir(110). Ir(100) can dissociate N2 directly on H site and Ir(110) should firstly capture N2 via bridge site and further transfer the adsorbed N2 to the H site, which will dramatically deteriorate the reactivity of N2 dissociation. In addition, the following protonation processes of dissociated *N atoms are all exothermal at 348 K on Ir(100), indicating that the ammonia synthesis can occur spontaneously as the temperature higher than 348 K. These results have provided a reasonable materials design scheme for subsequent ammonia synthesis.
Achieving efficient adsorption and separation of C2H2/CO2 mixtures is a goal that people have always pursued to improve the situation of high energy consumption brought by traditional separation technologies in industry today. High-nuclearity metal cluster-based MOFs with different functionalities are promising for this separation, but it is a complicated and difficult task to precisely control their structures. The strategy of pore-space partition (PSP) is a powerful way to construct this type MOFs, which has the characteristic of isostructural relationship, and can be resulted in a similar performance for them. Therefore, it is an interesting work to explore the effect of MOFs property by adjusting the size of PSP dividers. Herein, three tetranuclear Cu(Ⅱ) cluster-based MOFs (FJU-112/113/114) with dual functionalities has been successfully obtained by PSP strategy with various lengths of divider units. With the highest microporosity and unique functional site, FJU-114 realized a good improvement in the adsorption and separation performance of C2H2/CO2. The gas adsorption and lab-scale C2H2/CO2 breakthrough experiments demonstrated that FJU-114 exhibits the highest adsorption uptake of 77 cm3/g for C2H2, and shows the best separation factor of 4.2 among three MOFs. The GCMC simulation reveals that a stronger adsorption binding site of C2H2 in FJU-114a located in the cage Ⅱ near the unchanged tetranuclear copper node, combined with its high microporosity to achieve the effect of dual functionalities for the improvement performance of C2H2 adsorption and separation.
Large-scale deployment of carbon dioxide (CO2) removal technology is an essential step to cope with global warming and achieve carbon neutrality. Direct air capture (DAC) has recently received increasing attention given the high flexibility to remove CO2 from discrete sources. Porous materials with adjustable pore characteristics are promising sorbents with low or no latent heat of vaporization. This review article has summarized the recent development of porous sorbents for DAC, with a focus of pore engineering strategy and adsorption mechanism. Physisorbents such as zeolites, porous carbons, metal-organic frameworks (MOFs), and amine-modified chemisorbents have been discussed and their challenges in practical application have been analyzed. At last, future directions have been proposed, and it is expected to inspire collaborations from chemistry, environment, material science and engineering communities.
As hydrogen energy technologies gain momentum, the role of renewable energy in facilitating sustainable hydrogen production is becoming increasingly critical. As a hydrogen production method, water electrolysis has attracted much attention from researchers due to its operational simplicity, the high purity of the hydrogen generated, and its potential for achieving zero carbon emissions throughout the process. Numerous studies has been manipulated on platinum (Pt)-based catalysts, which exhibit superior performance in hydrogen evolution reactions. Within this category, Pt nanoclusters stand out due to their unique attributes, such as quantum size effects and unique coordination environments. These features enable them to outperform both Pt metal atoms and nanoparticles in hydrogen evolution reactions regarding activity and stability. Here, we primarily delve into the reaction mechanisms underlying Pt nanocluster-based hydrogen catalysts, with particular emphasis on the interactions between the metal catalysts and their associated support materials. We provide an exhaustive summary of the strategies employed in the synthesis, the structural analyses conducted, and the performance metrics observed for Pt nanocluster catalysts when paired with various supporting materials. In closing, we explore the future potential and challenges facing Pt nanocluster-based catalysts in the context of industrial water electrolysis, along with emerging avenues for their design and optimization.
Van der Waals (vdW) ferroelectric-semiconductor heterojunction provides reconfigurable band alignment based on optical/electrical-assisted polarization switching, which shows great potential to construct artificial visual neural systems. However, the mechanical exfoliation fabrication scheme for proof-of-concept demonstrations and fundamental studies is cumbersome and not scalable for practical application. Here, we present a synthetic strategy for the large-scale and high crystallinity growth of planar/vertical α-In2Se3/MoS2 heterojunctions by dynamically tuning the growth temperature. Furthermore, based on the α-In2Se3/MoS2 heterostructures, photo-synapse devices are designed and fabricated to simulate visual neural systems functions, including multistate storage, optical logic operation, potentiation and depression, paired-pulse facilitation (PPF), short-term memory (STM), long-term memory (LTM), and Learning-Forgetting-Relearning. By coupling the spatiotemporally relevant optical and electric information, the device can mimic the superior biological visual system's light adaptation and Pavlovian conditioning. This work provides a strategy for dynamically tuning the orientation of ferroelectric-semiconductor heterojunction stacks and will give impetus to applying all-in-one sensing and memory-computing artificial vision systems.
The performance optimization of materials is an eternal theme and challenge in scientific research, which is reflected in ferroelectric filed to two hot topics of enhancing Curie temperature (TC) and functional versatility. The former one vitally determines ferroelectric operational temperature range while the latter would open up new application possibilities. Effective chemical modification or doping strategies on A-site and X-site components have been successfully developed in hybrid organic-inorganic perovskite (HOIP) ferroelectrics, however, the important role of adjusting B-site ions has long been overlooked. Here, we have implemented regulation on the ion radius of the B-site component to successfully obtain two new HOIP ferroelectrics (3-pyrrolinium)BBr3 (B = Mn and Ni). Compared to parent (3-pyrrolinium)CdBr3, the TC (ΔT = 99 K) was significantly optimized by replacing the Cd2+ with smaller Mn2+ or Ni2+ ions. More strikingly, the introduction of Mn2+ and Ni2+ ions with octahedral coordination bring out intriguing red emission and magnetism respectively, making the multifunctional integration in a single material for multiple uses. This work provides a feasible strategy for performance optimizing of HOIP ferroelectrics, and would shed light for constructing multifunctional ferroelectrics.
Lithium-sulfur batteries are considered to be a new generation of high energy density batteries due to their non-toxicity, low cost and high theoretical specific capacity. However, the development of practical lithium-sulfur batteries is seriously impeded by the sluggish multi-electron redox reaction of sulfur species and obstinate shuttle effect of polysulfides. In this study, a porous lanthanum oxychloride (LaOCl) nanofiber is designed as adsorbent and electrocatalyst of polysulfides to regulate the redox kinetics and suppress shuttling of sulfur species. Benefiting from the porous architecture and luxuriant active site of LaOCl nanofibers, the meliorative polarization effect and sulfur expansion can be accomplished. The LaOCl/S electrode exhibits an initial discharge specific capacity of 1112.3 mAh/g at 0.1 C and maintains a superior cycling performance with a slight decay of 0.02% per cycle over 1000 cycles at 1.0 C. Furthermore, even under a high sulfur loading of 4.6 mg/cm2, the S cathode with LaOCl nanofibers still retains a high reversible areal capacity of 4.2 mAh/cm2 at 0.2 C and a stable cycling performance. Such a porous host expands the application of rare earth based catalysts in lithium-sulfur batteries and provides an alternative approach to facilitate the polysulfides conversion kinetics.
The large current density of electrochemical CO2 reduction towards industrial application is challenging. Herein, without strong acid and reductant, the synthesized BiVO4 with abundant oxygen vacancies (Ovs) exhibited a high formate Faradaic efficiency (FE) of 97.45% (-0.9 V) and a large partial current density of -45.82 mA/cm2 (-1.2 V). The good performance benefits from the reconstruction of BiVO4 to generate active metal Bi sites, which results in the electron redistribution to boost the OCHO* formation. In flow cells, near industrial current density of 183.94 mA/cm2 was achieved, with the FE of formate above 95% from 20 mA/cm2 to 180 mA/cm2. Our work provides a facily synthesized BiVO4 precatalyst for CO2 electroreduction.
Anode active materials involving transition metal oxides and sulfides are of great significance for high energy density lithium-ion batteries (LIBs), but the huge volume expansion and inferior electronic conductivity upon cycling critically constrain their further application. Herein, from a new perspective, a highly conductive and stable 3D flexible composite current collector is rationally designed by facilely electrodepositing metallic Ni thin layer onto the carbon cloth (CC/Ni), which endows the supported active materials with exceptional electronic conductivity and structural stability. In addition, the homogeneously distributed metallic Ni protrusions external CC can strongly bond with the active components, ensuring the structural integrity of electrodes upon cycling. More importantly, the 3D network structure with large specific surface area provides abundant space to alleviate the volume expansion and more active sites for electrochemical reactions. Therefore, taking Ni3S2 nanosheet (Ni3S2 NS) anode as an example, the prepared Ni3S2 NS@CC/Ni electrode shows a high specific capacity of 2.32 mAh/cm2 at 1 mA/cm2 and high capacity retention of 1.68 mAh/cm2 at a high rate of 8 mA/cm2. This study provides a universal approach to obtain highly conductive and stable 3D flexible current collectors towards high performance metal-ion batteries beyond LIBs.