Janus NiN4–CuN4 catalyst supported by a double-layered ZIF-8 structure for CO2 electrocatalytic reduction to C2+ products

Abstract

Copper (Cu)-based catalysts exhibit considerable potential for the electrocatalytic CO₂ reduction reaction (CO₂RR) to multi-carbon (C₂₊) products; nevertheless, competitive products (e.g., formic acid) have also been produced by thermodynamic constraints. The attainment of selective C₂₊ products exhibiting high faradaic efficiency (FE) and current density remains a significant challenge. Here, we designed a tandem catalytic strategy and prepared a series of Janus catalysts supported by double-layered ZIF-8 with inner MN₄ and outer CuN₄ for C₂₊ products (especially n-propanol). The synthetic catalyst, NiN₄@CuN₄, achieved high faradaic efficiencies of 80.6% for C₂₊ at −1.6 V in a flow cell, with 24.4% n-propanol (CH₃CH₂CH₂OH) and 36.6% ethanol (CH₃CH₂OH). In situ Raman experiments along with mechanism analysis indicate that the synergistic interaction of inner NiN₄ and outer CuN₄ significantly facilitates CO production and CO electroreduction, thereby greatly promoting C₂₊ production.