CO2 reduction to formic acid via NH2-C@Cu2O photocatalyst in situ derived from amino modified Cu-MOF

Abstract

Photocatalytic CO2 reduction is a green and environmentally friendly carbon conversion technology, which can vigorously promote the realization of the goals of "carbon neutrality" and " peak carbon dioxide emissions ". Herein, the -NH2 modified carbon frame decorated Cu2O (NH2-C@Cu2O) photocatalyst was synthesized by the metal organic framework (NH2-Cu-MOF) under the low temperature carbonization (300 ℃). During the low temperature annealing process, the organic ligand would self-converted into amorphous carbon, which could promote the photogenerated electron transfer and inhibit the photo-corrosion of Cu2O. According to in-situ FTIR analysis, the modification of amino group could greatly promote the chemisorption of CO2 by strong interaction with acid and base between -NH2 and CO2. Moreover, NH2-C@Cu2O preferred to form HCOO− intermediates instead of others, thus improved the selectivity of CO2 reduction to HCOOH. Simultaneously, the amino functionalization could further inhibit carrier recombination due to its electron-acceptor properties. Compared with pure Cu2O, a 3-fold enhancement for HCOOH yield rate was achieved. This work provides new ideas for the design of highly efficient and stable photocatalysts, and also contributes to the realization of the “double carbon goal”.