Electrocatalysis for CO2 and CO Reduction

Abstract

Renewable energy-driven electroreduction of CO2 represents a promising approach toward artificial carbon recycling. Electrolytes of high alkalinity are known to favor C-C coupling, a key step toward value-added C2+ hydrocarbon products such as ethylene, ethanol, acetate and n-propanol. However, the undesired side reaction with CO2 has limited the practical implementation of alkaline electrolytes in CO2 electrolyzers. This challenge can be circumvented by sequential electroreduction of CO2 to CO and then CO to C2+. This presentation aims to introduce our efforts on the development of advanced electrocatalysts for CO2 and CO reduction. Topics to be covered include i) highly dense Cu nanowires with abundant grain boundaries and undercoordinated surfaces, ii) Cu nanocrystals of well-controlled shapes and iii) bimetallic electrocatalysts with controlled atomic ensembles. Atomic structures of these nanostructures are characterized by using state-of-the-art electron microscopy and X-ray spectroscopy techniques. Surface structures and adsorption properties of the electrocatalysts are probed by measuring temperature- or potential-programed chemisorption of small molecules (e.g., COad and OHad). Kinetic analysis was performed to discern the rate-determining factors and reaction pathways. The established structure-property-performance correlations are further subjected to computational simulations to develop fundamental understanding of the catalytic mechanisms. Our work highlights the great potential of electrosynthesis with CO2 as the feedstock toward renewable hydrocarbons.