In situ synthesis of cubic PtPd bimetallic co-catalyst on C3N4 nanosheets for photocatalytic hydrogen generation

摘要

The severe recombination of photoinduced carriers is one of the major problems encountered in C3N4-based photocatalyst for hydrogen generation. Herein, PtPd/C3N4 composites by in situ growth of cubic PtPd bimetallic co-catalyst on the surface of C3N4 were constructed for photocatalytic hydrogen generation under visible light irradiation. The phase structure, microstructure, and optical property were characterized by X-ray diffraction, transmission electron microscopy, and UV-Vis diffuse reflectance spectroscopy. Photocatalytic hydrogen generation results showed that the growth of a moderate amount of cubic PtPd bimetallic co-catalyst on C3N4 is excellent beneficial for enhancing hydrogen generation activity. By optimizing the loading content of cubic PtPd bimetallic co-catalyst, the PtPd/C3N4 composite provided a maximum hydrogen generation rate of 54.31 mu mol h(-1). The enhancement of the photocatalytic activity can be attributed to the efficient separation and transfer of photoinduced carriers. On one hand, PtPd bimetal can extract electrons from C3N4, which promotes the separation efficiency of the carriers. On the other hand, the face-to-face interface formed between PtPd cubes and C3N4 nanosheets has a large contact area, resulting in lots of unique high-speed carrier transfer channels in PtPd/C3N4 composite, which promotes the transfer efficiency of the carriers. The work highlights the construction of less expensive and suitable shape of co-catalyst for enhanced photocatalytic activity.