Cu(In,Ga)Se2 for selective and efficient photoelectrochemical conversion of CO2 into CO

• DOI: 10.1016/j.jcat.2020.02.015
• Publication Date: 2020-03-09T02:29:53Z
• Authors: Zhuofeng Hu; Junbo Gong; Zi Ye; Yang Liu; Xudong Xiao; Jimmy C. Yu
• Keywords: Photocathode; Photocurrent; Photoelectrochemistry; Visible spectrum

Abstract The performance of photoelectrochemical (PEC) CO2 reduction on a photocathode is determined by the light absorption, charge separation and charge transfer efficiency of the photocathode according toηtotal = ηabs * ηsep * ηtran. Herein, we for the first time establish a photocathode for CO2 reduction on the base of commercially-available p-type Cu(In,Ga)Se2 (CIGS). CIGS has a very high optical absorption coefficient up to 105 cm−1 in wide wavelength region. It reaches an ultrahigh photocurrent density of 4.8 mA cm−2 at −0.2 V vs. RHE and 11.5 mA cm−2 at −0.7 V vs. RHE. Importantly, by fixing the bias at −0.2 V vs. RHE, the CIGS/CdS/ZnO/AZO photocathode selectively converts CO2 into CO with a faradaic efficiency of 99.3%. This is the highest record among the state-of-the-art photocathodes for CO2 to CO. Our work opens new opportunity for CIGS in solar-induced chemical reactions, and is expected to be concerned by researchers who are interested in catalysis and PECs.