Composition-Tuned Surface Binding on CuZn-Ni Catalysts Boosts CO₂RR Selectivity toward CO Generation

The Cu/Zn ratio of the CuZn electrocatalyst is known to influence the selectivity of CO₂RR, but questions remain open about how microstructure, crystal phase, and oxidation state of the metal ions change and interplay in the composition tuning process, which need to be carefully addressed for rational catalyst design. Toward this end, we designed and synthesized a series of CuZn-based aerogel materials with controlled Cu/Zn ratios and systematically investigated their effects on CO₂RR catalysis. From both experimental results and theoretical calculations, we found that the introduction of Zn into Cu aerogel greatly promoted the production of CO primarily due to the unfavorable adsorption energy of *H. Surprisingly, the intake of trace Ni atoms further inhibited the H₂ evolution reaction on account of the strong pinning of both *H and H₂O* on the Ni sites. Therefore, the as-formed CuZn-Ni aerogel exhibited a much-improved catalytic activity and selectivity for CO generation with FE­(CO) increased to 80% from 60%. This work gives insights into the surface adsorption–desorption characteristics underlying the activity and selectivity of electrocatalysts, which is of general importance for CO₂RR.