Hexagonal Zn Nanoplates Enclosed by Zn(100) and Zn(002) Facets for Highly Selective CO2 Electroreduction to CO.

Electrochemical reduction of CO2 to carbon-neutral fuels is a promising strategy for renewable energy conversion and storage. However, developing earth-abundant and cost-effective electrocatalysts with high catalytic activity and desirable selectivity for the target fuel is still challenging and imperative. Herein, hexagonal Zn nanoplates (H-Zn-NPs) enclosed by Zn(100) and Zn(002) facets were successfully synthesized and studied for their feasibility toward the CO2 reduction reaction (CO2RR). Compared with similarly sized Zn nanoparticles (S-Zn-NPs), the H-Zn-NPs exhibit remarkably enhanced current density, together with an improved CO faradaic efficiency (FE) of over 85% in a wide potential window, where a maximum FE of 94.2% is achieved. The enhancement in the CO2RR performance benefits from the substantial catalytically active sites introduced by the special architecture of H-Zn-NPs. Density functional theory calculations reveal that the exposed Zn(100) facets and edge sites on H-Zn-NPs are energetically favorable for CO2RR to CO, which directly result in an enhanced CO2RR performance. This study undoubtedly provides a straightforward approach to controlling the catalytic activity and selectivity of CO2RR through tuning the shape of Zn-based catalysts so as to maximize the percentage of exposed Zn(100) facets.