化学化工学院知识库

The photoelectrochemical (PEC) reduction of CO2 into organic chemicals on the semiconductor is considered a feasible plan to address the global energy crisis and climate warming. Herein, the heterojunctions NiMoO4/ZnO-x are designed and synthesized. The nanosheets of NiMoO4 have excellent absorption of photons and benefit the C-C coupling to C2 compounds. The ZnO/C core fabricated from MOF rich in CN species harvests light to generate a lot of thermal electrons assisting CO2 reduction. Benefitting from its unique chemical properties and structure, the as-prepared NiMoO4/ZnO-3 heterojunction exhibited impressive performance in CO2 reduction, yielding oxygenated chemicals with 72.6% selectivity for C2 products at a rate of 29.2 μM cm−2 h−1. The formation rate under photoelectrochemical conduction is three times that of photocatalysis plus electrocatalysis, showing a strong synergetic effect of photo- and electro-catalysis. The isotopic labeling experiments of 13CO2 verified that the products are derived from CO2 and water. Finally, a new catalytic mechanism with bimetallic centers is proposed firstly to explain the reaction pathways with high selectivity of C2 chemicals. The important intermediates and the C-C coupling via Ni-Mo bicentre are proven by density-functional theory (DFT) calculations and verified by operando Fourier transform infrared (FTIR) spectrometry. On the other hand, the effect of thermal electrons is investigated as well. © 2023 The Royal Society of Chemistry.