Construction of Cu-Modified g-C<sub>3</sub>N<sub>4</sub> Nanosheets for Photoinduced CO<sub>2</sub> Reduction to CO and Selectivity Mechanism Insight
Qi Qi, Wenjing Shen, Ming Cai, Junxi Cai, Bo Hu, Donglai Han, Xu Tang, Zhi Zhu, Pengwei Huo
Abstract
Graphite polymeric carbon nitride (PCN) has been extensively applied to photocatalytic CO 2 reduction reactions, which are expected to enhance the reaction activity and improve product selectivity by introducing transition metals. In this work, we successfully prepared Cu-modified PCN (Cu-PCN) by a thermal polymerization approach and conducted a systematic and comprehensive exploration of the photocatalytic reduction of CO 2 and selective generation of CO reactions. A series of experiments and DFT results attest that a tiny amount of Cu anchor on PCN, forming an active site for activating CO 2, can significantly mediate the electron transport to absorbed CO 2 molecul0065s through the Cu sites and improve the efficiency of the light-driven CO 2 reduction reaction. As-designed photocatalysts exhibit excellent photocatalytic reduction of CO 2 to a CO selectivity close to 100%. Detection of intermediates using in situ FT-IR reveals that *COOH is the critical intermediate and is a rate-limiting step in the overall reaction, which is consistent with DFT results. Our work makes up for these deficiencies in previous related research and provides a good reference for exploring the product selectivity of photocatalytic reduction of CO 2 .