Enhanced Photocatalytic Hydrogen Evolution of In2S3 by Decorating In2O3 with Rich Oxygen Vacancies

The hydrogen (H 2 ) evolution rates of photocatalysts suffer from weak oxidation and reduction ability and low photogenerated charge carrier separation efficiency. Herein, by combining band-gap structure optimization and vacancy modulation through a one-step hydrothermal method, In 2 O 3 containing oxygen vacancy (O v /In 2 O 3 ) is simply introduced into In 2 S 3 to promote photocatalytic hydrogen evolution. Specifically, the change in the sulfur source ratio can induce the coexistence of O v /In 2 O 3 and In 2 S 3 in a high-temperature hydrothermal process. Under light irradiation, In 2 S 3 @O v /In 2 O 3 -0.1 nanosheets hold a remarkable average H 2 evolution rate up to 4.04 mmol g –1 h –1, which is 32.14, 11.91, and 2.25-fold better than those of pristine In 2 S 3, In 2 S 3 @O v /In 2 O 3 -0.02, and In 2 S 3 @O v /In 2 O 3 -0.25 nanosheets, respectively. The ultraviolet–visible (UV–vis) diffuse reflectance and photoluminescence (PL) spectra reveal that the formation of O v /In 2 O 3 in In 2 S 3 optimizes the band-gap structure and accelerates the migration of the photogenerated charge carrier of In 2 S 3 @O v /In 2 O 3 - x nanosheets, respectively. Both the enhancement of oxidation and reduction ability and photogenerated charge carrier separation ability are responsible for the remarkable improvement in photocatalytic H 2 evolution performance. This work provides a new strategy to prepare a composite of metal sulfide and metal oxide through a one-step hydrothermal method.