Enhanced Photocatalytic Hydrogen Evolution of InS by Decorating InO with Rich Oxygen Vacancies.

The hydrogen (H) 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, InO containing oxygen vacancy (O/InO) is simply introduced into InS to promote photocatalytic hydrogen evolution. Specifically, the change in the sulfur source ratio can induce the coexistence of O/InO and InS in a high-temperature hydrothermal process. Under light irradiation, InS@O/InO-0.1 nanosheets hold a remarkable average H evolution rate up to 4.04 mmol g h, which is 32.14, 11.91, and 2.25-fold better than those of pristine InS, InS@O/InO-0.02, and InS@O/InO-0.25 nanosheets, respectively. The ultraviolet-visible (UV-vis) diffuse reflectance and photoluminescence (PL) spectra reveal that the formation of O/InO in InS optimizes the band-gap structure and accelerates the migration of the photogenerated charge carrier of InS@O/InO- 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 evolution performance. This work provides a new strategy to prepare a composite of metal sulfide and metal oxide through a one-step hydrothermal method.