Ultra-fast synthesis of three-dimensional porous Cu/Zn heterostructures for enhanced carbon dioxide electroreduction

The construction of metal hetero-interfaces has great potential in the application of electro-catalytic carbon dioxide reduction (ECR). Herein, we report a fast, efficient, and simple electrodeposition strategy for synthesizing three-dimensional (3D) porous Cu/Zn heterostructures using the hydrogen bubble template method. When the deposition was carried out at -1.0 A for 30 s, the obtained 3D porous Cu/Zn heterostructures on carbon paper (CP) demonstrated a nearly 100% CO faradaic efficiency (FE) with a high partial current density of 91.8 mA cm^-2 at -2.1 V vs. Ag/Ag⁺ in the mixed electrolyte of ionic liquids/acetonitrile in an H-type cell. In particular, the partial current density of CO could reach 165.5 mA cm^-2 and the FE of CO could remain as high as 94.3% at -2.5 V vs. Ag/Ag⁺. The current density is much higher than most reported to date in an H-type cell (Table S1). Experimental and density functional theory (DFT) calculations reveal that the outstanding electrocatalytic performance of the electrode can be ascribed to the formation of 3D porous Cu/Zn heterostructures, in which the porous and self-supported architecture facilitates diffusion and the Cu/Zn heterostructures can reduce the energy barrier for ECR to CO.