Metal-Semiconductor Heterojunction with Ohmic Contact Realizes Efficient Infrared-Light-Driven Photocatalysis.

Shang, Shu; Li, Lei; Qiu, Yanglin; Zhong, Xia; He, Xin; Zhang, Peng; Wang, Hui; Zhang, Xiaodong et al. · Nano Lett · 2024

basic_science · Level V

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Abstract

Efficient utilization of solar energy for photocatalytic applications, particularly in the infrared spectrum, is crucial for addressing environmental challenges and energy scarcity. Herein we present a general strategy for constructing efficient infrared-driven photocatalysts in a metal/semiconductor heterojunction with Ohmic contact, where metals with low work function as the infrared-light absorber and semiconductors with electron storage ability can overcome the unfavorable electron flowback. Taking the Ni<sub><i>x</i></sub>B/MO<sub>2</sub> (M = Ce, Ti, Sn, Ge, Zr, etc.) heterojunction as an example, both experimental and theoretical investigations reveal that the formation of an Ohmic contact facilitates the transfer of hot electrons from Ni<sub><i>x</i></sub>B to MO<sub>2</sub>, which are stored by the ion redox pairs for the variable valence character of M. As expected, the heterojunction exhibits remarkable photocatalytic activity under infrared light (λ ≥ 800 nm), as evidenced by the efficient photofixation of CO<sub>2</sub> to high-value-added cyclic carbonates. This study offers a general platform for designing infrared-light-driven photocatalysts.