Ag@Au Core-Shell Nanowires for Nearly 100 % CO2 -to-CO Electroreduction.

Abstract

Electrochemical reduction of carbon dioxide (CO2 ) to CO is regarded as an efficient method to utilize the greenhouse gas CO2 , because the CO product can be further converted into high value-added chemicals via the Fisher-Tropsch process. Among all electrocatalysts used for CO2 -to-CO reduction, Au-based catalysts have been demonstrated to possess high selectivity, but their precious price limits their future large-scale applications. Thus, simultaneously achieving high selectivity and reasonable price is of great importance for the development of Au-based catalysts. Here, we report Ag@Au core-shell nanowires as electrocatalyst for CO2 reduction, in which a nanometer-thick Au film is uniformly deposited on the core Ag nanowire. Importantly, the Ag@Au catalyst with a relative low Au content can drive CO generation with nearly 100 % Faraday efficiency in 0.1 m KCl electrolyte at an overpotential of ca. -1.0 V. This high selectivity of CO2 reduction could be attributed to a suitable adsorption strength for the key intermediate on Au film together with the synergistic effects between the Au shell and Ag core and the strong interaction between CO2 and Cl- ions in the electrolyte, which may further pave the way for the development of high-efficiency electrocatalysts for CO2 reduction.