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

We loaded silver (Ag), as a hydrogen (H-2)-evolution cocatalyst, selectively onto zinc rhodium oxide (ZnRh2O4 (ZRO)), as a H-2-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 H-2 and O-2 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%.

Automated summary

The study achieved selective loading of Ag cocatalyst between ZRO and BVO via photodeposition method, with controlled Ag deposition which led to overall water splitting and increased generation of hydrogen and oxygen.