Rapid Microwave-Assisted Synthesis of ZnIn 2 S 4 Nanosheets for Highly Efficient Photocatalytic Hydrogen Production.

In this study, a facile and rapid microwave-assisted synthesis method was used to synthesize In 2 S 3 nanosheets, ZnS nanosheets, and ZnIn 2 S 4 nanosheets with sulfur vacancies. The two-dimensional semiconductor photocatalysts of ZnIn 2 S 4 nanosheets were characterized by XRD, FESEM, BET, TEM, XPS, UV-vis diffuse reflectance, and PL spectroscopy. The ZnIn 2 S 4 with sulfur vacancies exhibited an evident energy bandgap value of 2.82 eV, as determined by UV-visible diffuse reflectance spectroscopy, and its energy band diagram was obtained through the combination of XPS and energy bandgap values. ZnIn 2 S 4 nanosheets exhibited about 33.3 and 16.6 times higher photocatalytic hydrogen production than In 2 S 3 nanosheets and ZnS nanosheets, respectively, under visible-light irradiation. Various factors, including materials, sacrificial reagents, and pH values, were used to evaluate the influence of ZnIn 2 S 4 nanosheets on photocatalytic hydrogen production. In addition, the ZnIn 2 S 4 nanosheets revealed the highest photocatalytic hydrogen production from seawater, which was about 209.4 and 106.7 times higher than that of In 2 S 3 nanosheets and ZnS nanosheets, respectively. The presence of sulfur vacancies in ZnIn 2 S 4 nanosheets offers promising opportunities for developing highly efficient and stable photocatalysts for photocatalytic hydrogen production from seawater under visible-light irradiation.