Journal of Energy Chemistry ›› 2023, Vol. 86 ›› Issue (11): 391-398.DOI: 10.1016/j.jechem.2023.07.031

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Selectivity control of photocatalytic CO2 reduction over ZnS-based nanocrystals: A comparison study on the role of ionic cocatalysts

Hong Pangb,1, Fumihiko Ichiharac,1, Xianguang Menga, Lijuan Lia, Yuqi Xiaoa, Wei Zhoud,*, Jinhua Yeb,e,*   

  1. aHebei Provincial Laboratory of Inorganic Nonmetallic Materials, College of Materials Science and Engineering, North China University of Science and Technology, Tangshan 063210, Hebei, China;
    bInternational Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS), Tsukuba 305-0044, Japan;
    cCenter for Green Research on Energy and Environmental Materials (GREEN), National Institute for Materials Science (NIMS), Tsukuba 305-0044, Japan;
    dDepartment of Applied Physics, School of Science, Tianjin University, Tianjin 300072, China;
    eGraduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo 060-0814, Japan
  • Received:2023-06-03 Revised:2023-07-21 Accepted:2023-07-25 Online:2023-11-15 Published:2023-11-07
  • Contact: *E-mail addresses: mengxg_materchem@163.com (X. Meng), weizhou@tju.edu.cn (W. Zhou), jinhua.YE@nims.go.jp (J. Ye).
  • About author:1These authors contributed equally to this work.

Abstract: Taking copper doped ZnS (ZnS:Cu) nanocrystals as the main body of photocatalyst, the influence of different base transition metal ions (M2+ = Ni2+, Co2+, Fe2+ and Cd2+) on photocatalytic CO2 reduction in inorganic reaction system is investigated. Confined single-atom Ni2+, Co2+, and Cd2+ sites were created via cation-exchange process and enhanced CO2 reduction, while Fe2+ suppressed the photocatalytic activity for both water and CO2 reduction. The modified ZnS:Cu photocatalysts (M/ZnS:Cu) demonstrated tunable product selectivity, with Ni2+ and Co2+ showing high selectivity for syngas production and Cd2+ displaying remarkable formate selectivity. DFT calculations indicated favorable H adsorption free energy on Ni2+ and Co2+ sites, promoting the hydrogen evolution reaction. The selectivity of CO2 reduction products was found to be sensitive to the initial intermediate adsorption states. *COOH formed on Ni2+ and Co2+ while *OCHO formed on Cd2+, favoring the production of CO and HCOOH as the main products, respectively. This work provides valuable insights for developing efficient solar-to-fuel platforms with controlled CO2 reduction selectivity.

Key words: CO2 reduction, Photocatalysis, ZnS, Ionic cocatalyst, Formate, Syngas, DFT calculations