Ni‐Electrocatalytic CO2 Reduction Toward Ethanol

Abstract

AbstractThe electroreduction of CO2 offers a sustainable route to generate synthetic fuels. Cu‐based catalysts have been developed to produce value‐added C2+ alcohols; however, the limited understanding of complex C−C coupling and reaction pathway hinders the development of efficient CO2‐to‐C2+ alcohols catalysts. Herein, a Cu‐free, highly mesoporous NiO catalyst, derived from the microphase separation of a block copolymer, is reported, which achieves selective CO2 reduction toward ethanol with a Faradaic efficiency of 75.2% at −0.6 V versus RHE. The dense mesopores create a favorable local reaction environment with CO2‐rich and H2O‐deficient interfaces, suppressing hydrogen evolution and maximizing catalytic activity of NiO for CO2 reduction. Importantly, the C1‐feeding experiments, in situ spectroscopy, and theoretical calculations consistently show that the direct coupling of *CO2 and *COOH is responsible for C−C bond formation on NiO, and subsequent reduction of *CO2‐COOH to ethanol is energetically facile through the *COCOH and *OC2H5 pathway. The unconventional C−C coupling mechanism on NiO, in contrast to the *CO dimerization on Cu, is triggered by strong CO2 adsorption on the polarized Ni2+‐O2− sites. The work not only demonstrates a highly selective Cu‐free Ni‐based alternative for CO2‐to‐C2+ alcohols transformation but also provides a new perspective on C−C coupling toward C2+ synthesis.