In situ grown heterojunction of Bi2WO6/BiOCl for efficient photoelectrocatalytic CO2 reduction

• DOI: 10.1016/j.jcat.2019.06.007
• Publication Date: 2019-08-03T04:44:41Z
• Authors: Jixian Wang; Yan Wei; Bingjie Yang; Bing Wang; Jiazang Chen; Huanwang Jing
• Keywords: Crystal (programming language); Photocathode; Quantum Efficiency

Abstract CO2 reduction is a very attractive research field in environmental, material, and chemical science in light of the energy crisis and the greenhouse effect. In this study, Bi2WO6/BiOCl heterojunctions were fabricated onto the F-SnO2 transparent conductive glass in situ by a hydrothermal method. These new photocathodes, named BCW-X, were characterized by such methods as scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscope, and UV-vis spectra. Their morphology is a good 2D layered/3D flower structure. The exposed crystal plane of BiOCl was changed from (1 0 1) of the pristine form to (1 1 2) in the heterojunction. The photoelectrocatalytic reduction of CO2 was carried out in BCW-X|KHCO3|BiVO4 under irradiation by an Xe lamp and external voltage from a Si solar cell (−0.6 to −1.1 V). A PEC cell of BCW-6|KHCO3|BiVO4 produces ethanol at a rate of 11.4 μM h−1 cm−2 (600 μmol h−1 g−1) with 80.0% selectivity under −1.0 V. The apparent quantum efficiency is up to 0.63%, about three times that of composite BiOCl–Bi2WO6 as photocathode. These phenomena can be attributed to the better photogenic electron–hole separation and high charge separation efficiency of heterojunctions.