Porous Zn Conformal Coating on Dendritic-Like Ag with Enhanced Selectivity and Stability for CO2 Electroreduction to CO

With increasing CO2 emission and energy scarcity, electrocatalytic CO2 reduction reaction (CO2RR) offers an attractive solution for CO2 resource utilization using sustainable electrical energy. Ag-based catalysts with high-curvature nanoneedle structure exhibit the potential to achieve high CO2RR activity, but suffer from insufficient stability due to the vulnerability of the high-curvature structure during CO2RR. Herein, the uniform porous Zn conformal coating on high-curvature dendritic Ag nanoneedles (AgNNs@Zn) by vacuum thermal evaporation is prepared. As the surface sacrificial shell, the dissolution and reconstruction of Zn protect the inner Ag core, thus enhancing the CO2RR stability of AgNNs@Zn. The concentration of Ag+ in the electrolyte after 2 h CO2RR electrolysis markedly reduces from 2.4 ug L-1 in AgNNs to 1.4 ug L-1 in AgNNs@Zn. Moreover, the DFT calculation reveals that the constructed Ag-Zn interfaces can stabilize the *COOH intermediates, which promote the selectivity of CO2 reduction into CO. As a result, the optimized AgNNs@Zn catalyst exhibits the FECO of approximate to 91% at -0.86 V versus RHE in H-cell, and FECO of 90% at 100 mA cm(-2) above 12 h in flow cell. This work provides a feasible strategy to synthesize bimetallic catalysts with core-shell structure for better CO2RR performance.