Silver cocatalyst-concentration dependence of overall water splitting performance over silver-inserted solid-state heterojunction photocatalyst composed of zinc rhodium oxide and bismuth vanadium oxide

• Published in: Applied catalysis. B, Environmental Vol. 284; p. 119744
• Main Authors: Irie, Hiroshi, Yoda, Masaomi, Takashima, Toshihiro, Osaki, Junya
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 05-05-2021; Elsevier BV
• Subjects: Bismuth; Bismuth vanadium oxide; Cocatalyst; Conducting layer; Evolution; Heterojunctions; Hydrogen evolution; Irradiation; Light irradiation; Photocatalysts; Quantum efficiency; Rhodium; Silver; Two-step overall pure water-splitting; Vanadium; Vanadium oxides; Water splitting; Zinc; Zinc rhodium oxide; Two-step overall pure water-splitting; Silver; Cocatalyst; Conducting layer; Bismuth vanadium oxide; Zinc rhodium oxide
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2020.119744

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•We succeeded in selectively succeeded loading Ag onto ZnRh2O4 as a cocatalyst.•The photocatalyst is a solid-state Ag-inserted ZnRh2O4 and Bi4V2O11.•The selective loading was achieved by only the photoexcitation of ZnRh2O4.•All the Ag-loaded photocatalysts enhanced the overall water splitting activity.•AQE increased up to 1.1 wt% of Ag cocatalyst and tended to saturate up to 4.0 wt%.
We loaded silver (Ag), as a hydrogen (H2)-evolution cocatalyst, selectively onto zinc rhodium oxide (ZnRh2O4 (ZRO)), as a H2-evolution photocatalyst, with various amounts of the Ag cocatalyst in a heterojunction photocatalyst, Ag-inserted ZRO and bismuth vanadium oxide (Bi4V2O11 (BVO), ZRO/Ag/BVO). The selective loading of the Ag cocatalyst was realized by a photodeposition method by utilizing the bandgap difference between ZRO (1.2 eV) and BVO (1.7 eV), and the amount of deposited Ag was controlled by the photodeposition time to generate Ag/ZRO/Ag/BVO with up to 4.0 wt% of Ag cocatalyst. All the prepared Ag/ZRO/Ag/BVO proceeded overall water splitting under red light irradiation at a wavelength of 700 nm, enhancing the stoichiometric evolutions of H2 and O2 from water. Also, the apparent quantum efficiency increased up to 1.1 wt% of Ag cocatalyst and then tended to saturate in the measurement range up to 4.0 wt%.