Electron transfer in Cu/Cu2O generated by disproportionation promoting efficient CO2 photoreduction
Qian Zhu, Kainan Zhu, Minmin Cai, Yaowen Zhang, Zhiyu Shao, Mengpei Jiang, Xiyang Wang, Zhibin Geng, Xiaofeng Wu, Man‐Rong Li, Keke Huang, Shouhua Feng
Abstract
Constructing a high-efficiency composite material for CO 2 photoreduction is a key step to the achievement of carbon neutralization, but a comprehensive understanding of the factors that dictate CO 2 reduction activity remains elusive. Here, we constructed a series of Cu in situ combined on Cu 2 O (Cu/Cu 2 O-1, -2, -3) via an acid disproportionation method with various processing time. The optimal photocatalyst (Cu/Cu 2 O-2) affords CO at a rate of 10.43 µmol·g −1 ·h −1 , which is more than fourfold to that of pristine Cu 2 O. Electron transfer in the samples was detected by X-ray absorption spectroscopy (XAS) as well as X-ray photoelectron spectroscopy (XPS). Interestingly, the best photoreduction performance was not achieved by the sample possessing the most electron transfer (Cu/Cu 2 O-1) but by the one with moderate electron transfer (Cu/Cu 2 O-2). By virtue of density functional theory (DFT) calculations, a linear relationship between Bader charge variation (Δ q ) of the active sites and adsorption energy of CO 2 reduction intermediates was discovered, wherein the moderate charge transfer corresponds to appropriate adsorption energy, which benefits CO 2 photoreduction activity substantially. This work provides guidance for the construction of composite catalysts for efficient CO 2 photoreduction in a perspective of the quantity of electron transfer.