p‐n Heterojunction Constructed by Sea Urchin MgAl‐LDH/Co3O4 to Accelerate Photogenerated Carrier Flow

Photocatalytic hydrogen production is the most promising solution to environmental pollution and energy crisis. A reasonable construction of heterojunction is one of the common methods to improve photocatalytic hydrogen production. The nanosheet MgAl‐LDH and Co 3 O 4 form a sea urchin‐like MgAl‐LDH/Co 3 O 4 p‐n heterojunction by electrostatic self‐assembly. Under the irradiation of light, the hydrogen yield of the composite catalyst will reach 120 μmol in 5 h. Compared with Co 3 O 4 , it is six times higher. This is because, after the successful coupling of the two semiconductors, an internal electric field is generated on the surface of the material, which accelerated the flow of photogenerated carriers, thus improving the photocatalytic performance of the material. XRD, SEM, FTIR, and TEM confirm the successful synthesis of the composite catalyst. In XPS analysis, strong interaction between electrons is found. In addition, the photoluminescence spectra and electrochemical analysis are used to compare the photogenic electron production and transfer rates of different catalysts. Based on the above analysis combined with UV–vis DRS diffuse reflection spectroscopy and BET characterization, a possible hydrogen evolution principle is proposed and analyzed.