查看更多>>摘要：Unravelling the influence of strain and geometric effects on the electrochemical reduction of carbon dioxide(CO2RR)on Cu-based(or Pd-based)alloys remains challenging due to complex local microenvironment variables.Herein,we employ two PdCu alloys(nanoparticles and nanodendrites)to demonstrate how CO2RR selectivity can shift from CO to HCOO-.Despite sharing consistent phases,exposed crystal facets,and overall oxidative states,these alloys exhibit different local strain profiles due to their distinct geometries.By integrating experimental data,in-situ spectroscopy,and density functional theory calculations,we revealed that CO2 prefers adsorption on tensile-strained areas with carbon-side geometry,following a*COOH-to-CO pathway.Conversely,on some compressive-strained regions induced by the dendrite-like morphology,CO2 adopts an oxygen-side geometry,favoring an *OCHO-to-HCOO pathway due to the downshift of the d-band center.Notably,our findings elucidate a dominant *OCHO-to-HCOO-pathway in catalysts when featuring both adsorption geometries.This research provides a comprehensive model for local environment of bimetallic alloys,and establishes a clear relationship between the CO2RR pathway shift and variation in local strain environments of PdCu alloys.
查看更多>>摘要：Electronic perturbation of the surfaces of Cu catalysts is crucial for optimizing electrochemical CO2 reduction activity,yet still poses great challenges.Herein,nanostructured Cu nanowires(NW)with fine-tuned surface electronic structure are achieved via surface encapsulation with electron-withdrawing(-F)and-donating(-Me)group-functionalized graphdiynes(R-GDY,R=-F and-Me)and the resulting catalysts,denoted as R-GDY/Cu NW,display distinct CO2 reduction performances.In situ electrochemical spectroscopy revealed that the *CO(a key intermediate of the CO2 reduction reaction)binding affinity and consequent *CO coverage positively correlate with the Cu surface oxidation state,leading to favorable C-C coupling on F-GDY/Cu NW over Me-GDY/Cu NW.Electrochemical measurements corroborate the favorable C2H4 production with an optimum C2+selectivity of 73.15％±2.5％observed for F-GDY/Cu NW,while the predominant CH4 production is favored by Me-GDY/Cu NW.Furthermore,by leveraging the*Cu-hydroxyl(OH)/*CO ratio as a descriptor,mechanistic investigation reveals that the protonation of distinct adsorbed *CO facilitated by*Cu-OH is crucial for the selective generation of C2H4 and CH4 on F-GDY/Cu NW and Me-GDY/Cu NW,respectively.
查看更多>>摘要：High-efficiency electrocatalysis could serve as the bridge that connects renewable energy technologies,hydrogen economy and carbon capture/utilization,promising a sustainable future for humankind.It is therefore of paramount significance to explore feasible strategies to modulate the relevant electrocatalytic reactions and optimize device performances so as to promote their large-scale practical applications.Microenvironment regulation at the catalytic interface has been demonstrated to be capable of effectively enhancing the reaction rates and improving the selectivities for specific products.In this review we summarize the latest advances in microenvironment regulation in typical electrocatalytic processes(including water electrolysis,hydrogen-oxygen fuel cells,and carbon dioxide reduction)and the related in situ/operando characterization techniques and theoretical simulation methods.At the end of this article,we present an outlook on development trends and possible future directions.
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