Ultrathin Conductor Enabling Efficient IR Light CO2 Reduction

• Published in: Journal of the American Chemical Society 2019-01, Vol.141 (1), p.423-430
• Main Authors: Li, Xiaodong, Liang, Liang, Sun, Yongfu, Xu, Jiaqi, Jiao, Xingchen, Xu, Xiaoliang, Ju, Huanxin, Pan, Yang, Zhu, Junfa, Xie, Yi
• Format: Article
• Language: English
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/jacs.8b10692

The concurrent transformation of carbon dioxide and water into hydrocarbons and oxygen by low-photonic-energy IR light still represents a huge challenge. Here, we design an ultrathin conductor system, in which the special partially occupied band serves as the mediator to simultaneously guarantee IR light harvesting and satisfy band-edge positions, while the ultrathin configuration improves charge separation rates and surface redox kinetics. Taking the low cost and earth-abundant CuS as an example, we first fabricate ultrathin CuS layers, where temperature-dependent resistivities, valence-band spectra, and theoretical calculations affirm their metallic nature. Synchrotron-radiation photoelectron and ultraviolet–visible–near-infrared spectra show that metallic CuS atomic layers could realize a new cooperative intraband–interband transition under IR light irradiation, where the generated electrons and holes could simultaneously involve the carbon dioxide reduction and water oxidation reactions. As a result, CuS atomic layers exhibit nearly 100% selective CO production with an evolution rate of 14.5 μmol g–1 h–1 under IR light irradiation, while the catalytic performance shows no obvious decay after a 96 h test. Briefly, benefiting from ultrahigh conductivity and a unique partially occupied band, abundant conductor materials such as conducting metal sulfides and metal nitrides hold great promise for applications as effective IR light responsive photocatalysts.