Fabrication of black NiO/Sr2FeTaO6 heterojunctions with rapid interface charge transfer for efficient photocatalytic hydrogen evolution

Guiyun Yu; Jiawei Hu; Wen Xiao; Yongtai Zhu; Yong Dai

doi:10.3389/fchem.2022.1118540

Fabrication of black NiO/Sr₂FeTaO₆ heterojunctions with rapid interface charge transfer for efficient photocatalytic hydrogen evolution

Front Chem. 2023 Jan 6:10:1118540. doi: 10.3389/fchem.2022.1118540. eCollection 2022.

Authors

Guiyun Yu¹, Jiawei Hu², Wen Xiao², Yongtai Zhu³, Yong Dai¹

Affiliations

¹ School of Chemistry and Chemical Engineering, Yancheng Institute of Technology, Yancheng, China.
² School of Materials Science and Engineering, Yancheng Institute of Technology, Yancheng, China.
³ Tianneng Carbon Co., Ltd, Yancheng, China.

Abstract

Series of black NiO/Sr₂FeTaO₆ (NiO/SFT) composites were synthesized by the combined processes of hydrothermal method and calcination treatment. The formed NiO was deposited on the surface of Sr₂FeTaO₆ to form a closely interfacial contact, leading to the formation of NiO/Sr₂FeTaO₆ heterojunction. The resulted samples were fully characterized by XRD, TEM, XPS, and UV-Vis DRS to gain their microstructure, crystal phase, atomic states and optical absorption properties. Introducing narrow-bandgap semiconductor of black NiO in NiO/Sr₂FeTaO₆ heterojunctions exhibits two major advantages. On the one hand, coupling with black NiO can significantly increase the light harvesting capacity of Sr₂FeTaO₆. On the other hand, the formed NiO/Sr₂FeTaO₆ heterojunctions benefited the separation and transfer of photogenerated charge carriers, which was confirmed by photo-electrochemical measurement, PL and TR-PL spectra. The activity of as-prepared samples was evaluated by photocatalytic hydrogen (H₂) evolution (PHE) under visible light irradiation. The resulted NiO/SFT composites showed the improved PHE efficiency than that of NiO and Sr₂FeTaO₆, owing to the synergistic effects of synergistic effects of heterojunction formation for the efficient charge carrier transfer/separation and increased light harvesting capacity. However, the excess amount of NiO loaded in NiO/SFT composites will restrain the light harvesting of Sr₂FeTaO₆ component and decrease, leading to the decreased PHE activity. Our work provided an insight on the construction of high-efficiency heterojunction photocatalysts for PHE reaction.

Keywords: NiO; Sr2FeTaO6; heterojunction; hydrogen evolution; photocatalysis.