Electrocatalysis

摘要： The advancement and growth of nanotechnology lead to realizing new and novel multi-metallic nanostructures with well-defined sizes and morphology,resulting in an improvement in their performance in various catalytic applications.The trimetallic nanostructured materials are synthesized and designed in different architectures for energy conversion electrocatalysis.The as-synthesized trimetallic nanostructures have found unique physiochemical properties due to the synergistic combination of the three different metals in their structures.A vast array of approaches such as hydrothermal,solvothermal,seedgrowth,galvanic replacement reaction,biological,and other methods are employed to synthesize the trimetallic nanostructures.Noteworthy,the trimetallic nanostructures showed better performance and durability in the electrocatalytic fuel cells.In the present review,we provide a comprehensive overview of the recent strategies employed for synthesizing trimetallic nanostructures and their energy-related applications.With a particular focus on hydrogen evolution,alcohol oxidations,oxygen evolution,and others,we highlight the latest achievements in the field.

摘要： Electrochemical CO_(2)reduction(ECR)powered by renewable energy sources provides a sustainable avenue to producing carbon-neutral fuels and chemicals.The design and development of high performance,cost-effective,and stable catalysts for ECR remain a focus of intense research.Here,we report a novel electrocatalyst,two-dimensional cadmium-based 1,4-benzenedicarboxylate metal-organic frameworks(Cd-BDC MOFs)which can effectively convert CO_(2)to CO with a faradaic efficiency(FE)of more than80.0%over the voltage range between-0.9 and-1.1 V(versus reversible hydrogen electrode,vs.RHE)in 0.1 mol·L^(-1) CO_(2)-saturated KHCO_(3)solution with an H-type cell,reaching up to 88.9%at-1.0 V(vs.RHE).The performance outperforms commercial CdO and many other MOF-based materials demonstrated in prior literature.The catalytic property can be readily tuned by manipulating synthesis conditions as well as electrolyte type.Especially,high CO FEs exceeding 90.0%can be attained on the Cd-BDC electrode at potentials ranging from-0.16 to-1.06 V(vs.RHE)in 0.5 mol·L^(-1) KHCO_(3)solution by using a gas diffusion electrode cell system.The maximum CO FE approaches~97.6%at-0.26 V(vs.RHE)and the CO partial geometric current density is as high as about 108.1 mA·cm^(-2) at-1.1 V(vs.RHE).This work offers an efficient,low cost,and alternative electrocatalyst for CO_(2)transformation.

摘要： Electrochemical reduction of CO_(2)to value-added chemicals using renewable electricity provides a promising strategy to achieve sustainable fuel production and carbon neutrality.Along with the development of electrocatalysts,fow cells with gas-diffusion electrodes(GDEs)have been used to reach commercially viable current densities for CO_(2)electrolysis,while the local environment and CO_(2)mass transport in the electrodes remain to be elucidated.In this review article,we highlight some insights into the microenvironment in the catalyst layer for CO_(2)electrolysis,including typical mass transport models for CO_(2)reduction in H-type cells and GDE fow cells,the effect of a hydrophobic microenvironment on CO_(2)mass transport and catalytic performance,and the formation of a gas/liquid balance and solid–liquid–gas interfaces for CO_(2)electrolysis.The insights and discussions in this article can provide important guidelines on the design of catalysts,electrodes,and electrolyzers for CO_(2)electrolysis,as well as other gas-involving electrocatalytic reactions.

摘要： Electrochemical nitrogen reduction reaction(e-NRR)under ambient conditions is an emerging strategy to tackle the hydrogen-and energy-intensive operations for traditional Haber-Bosch process in industrial ammonia(NH_(3))synthesis.However,the e-NRR performance is currently impeded by the inherent inertness of N_(2) molecules,the extremely slow kinetics and the overwhelming competition from the hydrogen evolution reaction(HER),all of which cause unsatisfied yield and ammonia selectivity(Faradaic efficiency,FE).Defect and interface engineering are capable of achieving novel physical and chemical properties as well as superior synergistic effects for various electrocatalysts.In this review,we first provide a general introduction to the NRR mechanism.We then focus on the recent progress in defect and interface engineering and summarize how defect and interface can be rationally designed and functioned in NRR catalysts.Particularly,the origin of superior NRR catalytic activity by applying these approaches was discussed from both theoretical and experimental perspectives.Finally,the remaining challenges and future perspectives in this emerging area are highlighted.It is expected that this review will shed some light on designing NRR electrocatalysts with excellent activity,selectivity and stability.

摘要： The corrosion and weaker interaction with metal catalysts of common carbon supports during electrocatalysis push the development of alternative supports materials. Titanium oxide-based materials have been widely explored as electrocatalysts supports in consideration of their chemical stability, strong interactions with metal catalyst and wider applications in electrocatalytic reactions as well as the improved electronic conductivity. This review summarizes recent research advances in engineering titanium oxide-based supports for the catalysts in electrocatalysis field to provide guidance for designing high performance non-carbon supported electrocatalysts. Typically, the titanium oxide-based supports are classified into shaped TiO_(2), doped TiO_(2), titanium suboxide and TiO_(2)-carbon composites according to the modification methods and corresponding preparation methods. Then the engineering strategies and electrocatalytic applications are discussed in detail. Finally, the challenges, future research directions and perspectives of titanium oxide-based supports for electrocatalysis are presented for practical applications.

摘要： Exploring efficient,cost-effective,and durable electrocatalysts for electrochemical oxygen evolution reaction(OER)is pivotal for the large-scale application of water electrolysis.Recent advance has demonstrated that the activity of electrocatalysts exhibits a strong dependence on the surface electronic structure.Herein,a series of ultrathin metal silicate hydroxide nanosheets(UMSHNs)M_(3)Si_(2)O_(5)(OH)_(4)(M=Fe,Co,and Ni)synthesized without surfactant are introduced as highly active OER electrocatalysts.Cobalt silicate hydroxide nanosheets show an optimal OER activity with overpotentials of 287 and 358 m V at 1 and 10 m A cm^(-2),respectively.Combining experimental and theoretical studies,it is found that the OER activity of UMSHNs is dominated by the metal-oxygen covalency(MOC).High OER activity can be achieved by having a moderate MOC as reflected by aσ^(*)-orbital(e_(g))filling near unity and moderate[3d]/[2p]ratio.Moreover,the UMSHNs exhibit favorable chemical stability under oxidation potential.This contribution provides a scientific guidance for further development of active metal silicate hydroxide catalysts.

摘要： The oxygen evolution reaction(OER)is an electrochemical bottleneck half-reaction in some important energy conversion systems(e.g.,water splitting),which is traditionally mediated by iridium oxides in acidic environment.Perovskite-structured Ir-containing oxides(e.g.,SrIrO_(3))are a family of striking electrocatalysts due to their high specific activity,but this excellent quality is difficultly transferred to a nano-electrocatalyst with large active surface and good structural stability.Here,we present a synthesis method that produces a 2D ultrathin{001}-faceted SrIrO_(3)perovskite(2D-SIO)with a thickness of∼5 nm and high surface area(57.6 m^(2)g^(−1)).We show that 2D-SIO can serve as a highly active and stable electrocatalytic nanomaterial for OER under acidic conditions.This perovskite nanomaterial produces 10 mA cm^(−2)current density at a low overpotential(η,243 mV),and maintains its catalytic activity after 5000 continuous cyclic measurements.Besides ultrathin structure and large surface area,the exposed{001}facets are found to be the most crucial and unique structural factor for achieving high catalytic activity and structural stability.Our joint experimental and theoretical results demonstrate that these advantageous microstructural features of 2D-SIO endow it with a strong capability to generate the key O^(*)intermediates,and thereby facilitate O–O bond formation and the OER.

摘要： Over the past few decades,the design and development of carbon materials have occurred at a rapid pace.In particular,these porous graphene-like carbon nitride materials have received considerable attention due to their superior structures and performances in the energy transformation field.In this review,nitrogenated holey two-dimensional graphene and polymeric carbon nitride will be discussed in depth.The structural properties,synthetic methods,and applications including electrocatalytic reactions,such as hydrogen evolution reaction,oxygen reduction reaction,oxygen evolution reaction,and nitrogen reduction reaction,will be presented in detail.Finally,we will present the outlooks on the current obstacles to the development of carbon nitride materials.This comprehensive understanding will help guide and motivate researchers to develop and modify carbon nitride materials with better properties in the future.

摘要： Electrocatalytic nitrogen reduction reaction(eNRR)with sustainable energy under ambient conditions represents an attractive approach to producing ammonia,but the design of the-state-of-the-art electrocatalyst with high efficiency and selectivity still faces formidable challenges.In contrast to traditional eNRR catalyst design strategies focusing on N≡N triple bond activation,we herein theoretically proposed an alternative strategy to improve eNRR performance via stabilizing the N_(2)H^(*)intermediate using catalysts with the frustrated Lewis pairs(FLPs),i.e.,transition metal(TM)atoms and boron(B)atom co-doped 2D black phosphorus(TM-B@BP).Our density functional theory(DFT)results reveal that the TM atom donates electrons to the adsorbed N_(2)molecule,while B atom provides empty orbital to stabilize the adsorption of N_(2)H^(*)intermediate.This framework successfully identifies five promising candidates(i.e.,Ti-B@BP,V-B@BP,Cr-B@BP,Mn-B@BP and Fe-B@BP)with low theoretical limiting potentials(−0.60,−0.41,−0.45,−0.43 and−0.50 V,respectively)and high selectivity for eNRR.We believe that the intermediate stabilization strategy introduced in current work offers a new opportunity to achieve accelerated and cost-effective ammonia synthesis with electrocatalysis.

摘要： Electrocatalytic carb on dioxide reducti on(CO_(2)R)presents a promising route to establish zero-e mission carb on cycle and store in termittent ren ewable energy into chemical fuels for steady energy supply.Methanol is an ideal energy carrier as alternative fuels and one of the most important commodity chemicals.Nevertheless,methanol is currently mainly produced from fossil-based syngas,the production of which yields tremendous carb on emission globally.Direct CO_(2)R towards metha nol poses great potential to shift the paradigm of methanol production.In this perspective,we focus our discussions on producing methanol from electrochemical CO_(2)R,using metallomacrocyclic molecules as the model catalysts.We discuss the motivation of having methanol as the sole CO_(2)R product,the documented application of metallomacrocyclic catalysts for CO_(2)R,and recent advance in catalyzing CO_(2) to methanol with cobalt phthalocyanine-based catalysts.We attempt to understand the key factors in determining the activity,selectivity,and stability of electrocatalytic CO_(2)-to-methanol conversion,and to draw mechanistic insights from existing observations.Finally,we identify the challenges hindering methanol electrosynthesis directly from CO_(2) and some intriguing directions worthy of further investigation and exploration.