Interfaced Ag/Cu nanostructures derived from metal thiolate nanoplates: A highly selective catalyst for electrochemical reduction of CO₂ to ethanol

Abstract

Selective reduction of CO2 into liquid products such as ethanol through electrochemical catalysis is promising in storing renewable energy in more deliverable chemicals and balancing the carbon footprint in the environment. However, the lack of efficient catalysts for electrochemical CO2 reduction reaction (eCO2RR) makes the promise challenging because the formation of C2+ alcohols requires coupling reactions between the shallow reduction intermediates and deep reduction intermediates that are usually difficult to form on uniform catalyst surfaces simultaneously with appropriate transient kinetics. Herein, we report a new strategy for synthesizing bimetallic nanostructures with high densities of interfaced Ag/Cu boundaries, which facilitate the coupling reaction of the high‐oxidation‐number intermediates (CO) formed on the Ag surface and the low‐oxidation‐number intermediates (CHx) formed on the Cu surface. The synthesis relies on the electrochemical reduction of bilayered nanoplates made of silver thiolate and copper thiolate, resulting in Ag/Cu nanostructures exposing Ag surface, Cu surface, and the Ag/Cu interfaced boundaries. Balancing the accessible surface areas of the Ag surface, Cu surface, and Ag/Cu boundaries is beneficial for maximizing the activity and selectivity of eCO2RR towards ethanol production. Faradaic efficiency of forming ethanol has been observed as high as about 50% using the Ag/Cu nanostructure catalyst with molar ratio nAg:nCu of 1:1. Moreover, the promoted coupling reaction at the Ag/Cu boundaries and surface modification with thiolate anions significantly suppress the undesirable hydrogen evolution reaction, particularly at high cathodic potentials, maintaining high energy efficiency for eCO2RR.

Thiosulfate-mediated seeded growth of Au@AuAg yolk–shell nanocubes with surface concavity: optical and catalytic properties

“…Benefiting from the integration of advanced structural features into one particle body, including stepped facets, bimetallic components, and hollow interiors, 30–33 the current Au@AuAg YSCNCs were expected to show enhanced catalytic performance as compared to their counterpart of Au@Ag core–shell nanocubes containing flat surface and solid interior. 34,35 Herein, we chose the reduction of 4-NP as the model reaction, since both Au and Ag have demonstrated catalytic effectiveness towards the reaction.…”

Two-dimensional Cu-based materials for electrocatalytic carbon dioxide reduction

“…Furthermore, the inevitable presence of competing H 2 evolution reaction (HER) in the cathode can directly lead to a significant reduction in the efficiency of CO 2 RR. 26 , 27 , 28 , 86 In summary, Cu-based catalysts face various challenges in CO 2 RR. High product selectivity, catalyst stability, electrochemical activity, and Faraday efficiency are all demanding.…”

Sn-based electrocatalysts for electrochemical CO2 reduction

“…On the other hand, metals like Bi, Pb, and Sb, although not depicted in the figure, still exhibit favorable characteristics for formate production. 83–86…”