Highthroughput Screening of CuBi Bimetallic Catalyst Array for Electrocatalytic CO₂ Reduction Reaction by Scanning...

The testing and evaluation of catalysts in CO₂ electroreduction is a very tedious process. To study the catalytic system of CO₂ reduction more quickly and efficiently, it is necessary to establish a method that can detect multiple catalysts at the same time. Herein, a series of CuBi bimetallic catalysts have been successfully prepared on a single glass carbon electrode by a scanning micropieptte contact method. The application of scanning electrochemical microscopy (SECM) enabled the visualization of the CO₂ reduction activity in diverse catalyst micro-points. The SECM imaging with Substrate generation/tip collection (SG/TC) mode was conducted on CuBi bimetallic micro-points, revealing that HER reaction emerged as the prevailing reaction when a low overpotential was employed. While the applied potential was lower than -1.5 V vs. Ag/AgCl, the reduction of CO₂ to formic acid became dominant. Increasing the bismuth proportion in the bimetallic catalyst can inhibit the hydrogen evolution reaction at low potential and enhances the selectivity of the CO product at high cathode overpotential. This research offers a novel approach to examining arrays of catalysts for CO₂ reduction.