High-performance Photoelectrocatalytic Reduction of CO2 by the hydrophilic–hydrophobic composite Cu-SnO2/ZIF-8
Dingding Zhang, Huimin Yang, Yupeng Li, Zhifang Li, Nan Gao, Wenjing Zhou, Zhenhai Liang
Abstract
Photoelectrocatalytic reduction CO 2 can solve energy shortages and environmental problems. However, the poor solubility and intense competition of the hydrogen evolution reaction (HER) seriously restrict CO 2 activation. Here, a hydrophilic–hydrophobic Cu-SnO 2 /ZIF-8 composite catalyst was constructed by compounding hydrophobic ZIF-8 with hydrophilic Cu-SnO 2 . Gas-phase CO 2 was directly used to improve the activation efficiency of CO 2 molecules, and hydrogen evolution was inhibited. Results showed that when the overpotential was as low as ~364 mV, the Faraday efficiency of formic acid reached 68.96%. The maximum current density approached 12.8 mA·cm -2 at -1.4V versus the Ag/AgCl electrode. The ZIF-8 unique structure promoted electron transfer and Cu-SnO 2 dispersion to provide additional active sites. The excellent photocatalytic performance of Cu-SnO 2 /ZIF-8 may be attributed to the special hydrophilic–hydrophobic structure and the small band gap that can absorb much visible light.