Ultrasonic assisted synthesis of Zn-Ni bi-metal MOFs for interconnected Ni-N-C materials with enhanced electrochemical reduction of CO2

Abstract

Zn-Ni bi-metal MOFs were employed as precursors to prepare Ni-N-doped porous interconnected carbon (NiNPIC) catalysts for enhanced electrocatalytic activity and selectivity of the CO2RR. It was found that the Ni load amounts could be precisely controlled by altering the Ni dosage in the bi-metal MOF precursors, and the gradually increased Ni-N species leads to the enhanced CO2RR performances. The high surface area as well as interconnected porous structures of the catalysts provide highly accessible Ni-N sites and convenient channel for mass diffusion, which gives rise to better electron transfer, lower interface resistance and high electrolyte/gases transport in the CO2RR. Thanks to these structural advantages, the optimized catalyst demonstrated efficient convert CO2 into CO with a current density of 10.2 mA cm−2 (113 mA mg−1), a FECO of 95.1%, a production rate of 542 μmol m−2 s−1 (36.1 μmol mg−1 min−1), and outstanding electrochemical stability at a moderate over-potential of 0.54 V (vs. the RHE).