Phosphorus ZIF-67@NiAl LDH S-scheme heterojunction for efficient photocatalytic hydrogen production

The spatial separation of photogenerated electrons and holes in ZIF-67@NiAl LDH semiconductor with strong redox capability was realized by three factors including the built-in electric field, band bending and coulomb attraction. Morphology regulation and heterojunction construction can effectively improve the utilization rate of photogenerated carriers and promote the catalytic activity. The introduction of P atom further promoted the application of photogenerated electrons in photocatalytic reaction of reducing water. • An S-scheme heterojunction composed of ZIF-67 and NiAl LDH was formed. • The migration rate of photocarriers is accelerated by the introduction of phosphorus. • The recombination of photoinduced electron-hole pairs was inhibited. • Highly improved photocatalytic hydrogen evolution activity was obtained. Reasonable control of the interface of semiconductor materials is one of the potential strategies to develop efficient solar photocatalysts for hydrogen production. In the S-scheme heterojunction, the valid electrons and holes are preserved and the meaningless photocarriers are reorganized. Using the strategy of band structure matching and morphology regulation, we tightly coupled ZIF-67 with NiAl LDH by electrostatic self-assembly method, and constructed ZIF-67@NiAl LDH composite catalyst with S-scheme heterojunction structure. In addition to improving the interfacial charge transfer efficiency of catalyst, the design of S-scheme charge transfer path can enhance the redox capacity of catalyst to a certain extent. The design of two-dimensional/one-dimensional spatial structure increases the contact interface between ZIF-67 and NiAl LDH, which is conducive to the production of active sites. In addition, the introduction of P accelerates the carrier separation efficiency. Finally, phosphating ZIF-67@NiAl LDH catalyst showed excellent hydrogen production activity (2.99 mmol g -1 h −1 ) with a 5 W LED as light source and eosin as a photosensitizer. This work provides experimental support and theoretical basis for the design of photocatalysts for efficient catalytic hydrogen evolution involving sacrificial reagents.