Acta Phys. -Chim. Sin.

• Accepted manuscript • Previous Articles    

Transforming the Charge Transfer Mechanism in the In2O3/CdSe-DETA Nanocomposite from Type-I to S-Scheme to Improve Photocatalytic Activity and Stability During Hydrogen Production

Zhen Li1, Wen Liu2, Chunxu Chen1, Tingting Ma2, Jinfeng Zhang3, Zhenghua Wang2   

  1. 1. School of Food Engineering, Anhui Science and Technology University, Fengyang 233100, Anhui Province, China;
    2. College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000, Anhui Province, China;
    3. School of Physics and Electronic Information, Huaibei Normal University, Huaibei 235000, Anhui Province, China
  • Received:2022-08-22 Revised:2022-09-05 Accepted:2022-09-20 Published:2022-09-29
  • Contact: Jinfeng Zhang;Zhenghua Wang;
  • Supported by:
    This work was supported by National Natural Science Foundation of China (51973078) and Natural Science Foundation of Anhui Province,China (2108085MB48).

Abstract: The problems associated with fossil fuel consumption are restricting human development and harming the environment.An effective way for solving the alluded problems is to develop technology for harnessing renewable clean energy.In recent years,hydrogen has been reported as a new source of clean energy.The combustion heat of hydrogen is very high and the product formed is only water,which fully conforms to the characteristics of green and sustainable energy.Therefore,finding a suitable method for producing hydrogen can effectively solve the current global energy crisis.Since titanium (IV) oxide was used as a photocatalyst to split water into hydrogen and oxygen in 1972,water splitting over semiconductor photocatalysts has been an interesting research topic in the past decades.Nevertheless,the inherent disadvantages of single-component photocatalysts limit their practical application and it is still challenging to circumvent those disadvantages.When compared with single-component photocatalysts,composite photocatalysts can more effectively separate photogenerated electrons and holes,thereby increasing the photocatalytic hydrogen evolution rate.Therefore,photocatalytic hydrogen evolution activity and stability can be optimized by selecting the appropriate photocatalytic mechanism (e.g.,S-scheme) at the heterojunction of composites.In this study,many single-component CdSe-DETA photocatalysts with different band gaps were synthesized by varying certain synthesis conditions.The results obtained showed that adjusting the band gap (2.31 eV) of CdSe-DETA led to superior photocatalytic hydrogen production activity but the stability of the photocatalyst was poor.Thereafter,we constructed an In2O3/CdSe-DETA nanocomposite by attaching CdSe-DETA nanoflowers to the surface of porous In2O3 nanosheets to improve the photocatalytic hydrogen evolution activity,stability,and photocurrent response.The type of heterojunction in the In2O3/CdSe-DETA nanocomposite can be varied through the band energy gap of CdSe-DETA.More specifically,the type of heterojunction can be switched from Type-I to S-scheme in the case of swelling of the band energy gap of CdSe-DETA.When compared with single-component photocatalysts and Type-I photocatalysts,the S-scheme In2O3/CdSe-DETA nanocomposite exhibited higher photocatalytic activity and stability.Therefore,we chose the In2O3/CdSe-DETA nanocomposite with an S-scheme heterojunction to obtain optimal photocatalytic activity and stability.Additionally,we confirmed the existence of an S-scheme heterojunction via differential charge density calculations combined with experimental results.The S-scheme heterojunction In2O3/CdSe-DETA nanocomposite effectively separated photogenerated electrons and holes as well as maximized the use of the conduction and valence bands of the composite for efficient and stable photocatalytic hydrogen evolution.Therefore,this study demonstrates a novel strategy for modulating the carrier transfer mechanism,which provides a reference for the development of efficient hydrogen evolution photocatalysts.

Key words: Band gap, S-scheme, Theoretical calculation, Hydrogen evolution, Photocorrosion


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