Fabrication of an oxysulfide of bismuth Bi2O2S and its photocatalytic activity in a Bi2O2S/In2O3 composite

• Hydrothermal synthesis of Bi2O2S.
• Bi2O2S has a smaller band gap than Bi2O3.
• Pt, Co3O4/Cr-TPPCl/Bi2O2S/In2O3 used for water splitting.

Oxide-chalcogenide semiconductors are proposed in order to attain a smaller band gap and improve efficiencies in comparison to oxides for light induced total water splitting. Dibismuthoxysulfide (Bi2O2S) was synthesized under relatively mild hydrothermal conditions. The synthesized compound was characterized by XRD, SEM and UV–vis DRS techniques. The band gap of 1.5 eV measured is smaller than 2.8 eV of bismuth oxide (Bi2O3). Photoelectrochemical studies showed that it is possible to utilize Bi2O2S and the Bi2O2S/In2O3 composite as n-type semiconductors. Dye modified Bi2O2S/In2O3 showed promise for the catalysis of water splitting.

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