Cobalt phosphate co-catalysts and boron-doped ZnIn2S4 nanosheets for efficient photocatalytic hydrogen conversion

In the quest for effective photocatalysts for hydrogen production via photocatalytic water splitting, ZnIn 2 S 4 has garnered considerable attention due to its high photocatalytic hydrogen evolution capability. In this study, boron-doped ZnIn 2 S 4 was successfully synthesized via a hydrothermal method , with a small amount of cobalt phosphate (Co-Pi) decorated on its surface. The hydrogen evolution rate of boron-doped ZnIn 2 S 4 was determined to be 5.2 mmol g −1  h −1 , surpassing that of pure ZnIn 2 S 4 by 1.68 times. Moreover, with the addition of Co-Pi to boron-doped ZnIn 2 S 4 , the hydrogen production rate escalated to 29.7 mmol g −1  h −1 , which is 9.58 times higher compared to pure ZnIn 2 S 4 . UV–vis analysis revealed that boron doping introduced new energy levels into ZnIn 2 S 4 , effectively narrowing the bandgap and enhancing light absorption wavelength range. Furthermore, PL and XPS analyses indicate that Co-Pi effectively captures photogenerated holes (h + ) in ZnIn 2 S 4 , retaining photogenerated electrons and overcoming the disadvantage of electron-hole pair recombination in ZnIn 2 S 4 . The doping and loading of Co-Pi as a cocatalyst ultimately contribute to enhancing hydrogen production efficiency, thereby significantly improving the photocatalytic hydrogen evolution capability of ZnIn 2 S 4 . This study provides a scalable idea for designing composite catalysts in which doping and co-catalysts work together.