Highly Selective Electrochemical Reduction of CO2 to CH4 over Vacancy Metal Nitrogen Sites in an Artificial Photosynthetic Cell

Copper-containing materials have been widely researched as promising catalysts for CO, electrochemical reduction reaction (CO2RR). However, several challenges remain with these materials, such as the aggregation of copper atoms into large-size nanoparticles, which decreases the number of active sites and the catalytic efficiency. Herein, bimetal pyrolyzed zeolite imidazole frameworks (ZIFs) of copper and zinc with various ratios were prepared, in which the aggregation of copper atoms was alleviated. CuN3(I) coordination active sites were fabricated and confirmed by synchrotron radiation spectra. The Cu1Zn1-N-C catalyst with maximum content of CuN3(I) demonstrated high CO2RR product selectivity of 95.6% toward CH4 gas fuel product in an artificial photosynthetic cell. Density functional theory calculations showed that the relative free energy of *CHO was the lowest on CuN3(I) coordination structure for reducing CO2 to CH4, which accounts for the high selectivity of Cu1Zn1-N-C catalyst in CO2RR.