Controlling size and distribution of Au nano-particles on C3N4 for high-efficiency photocatalytic hydrogen production.

ABSTRACT

With advantages such as low cost, high stability, and ease of production, visible light photocatalytic C3N4 with a unique microscopic layered structure holds significant potential for development. However, its hydrogen production efficiency remains low due to the pronounced recombination of photo-generated charge carriers and limited surface reaction sites. Normally, the photocatalytic performance of C3N4 can be enhanced by loading noble metals with surface plasmon resonance. It is worth noting that the size of noble metal nanoparticles has a great influence on photocatalytic performance. In this study, accurate controlling of the size and distribution of Au nanoparticles was achieved on the surface of C3N4 by introducing amino groups to improve photocatalytic performance. Results show that uniformly distributed Au nanoparticles in the range of 2-6 nm can be obtained on C3N4 with a remarkable enhancement of hydrogen production efficiency, which is about 114 times the property of pure C3N4. The small-sized and uniformly distributed Au nanoparticles can provide more reaction sites and increase the separation of photo-generated charge carriers, in turn improving Au/NH3-C3N4 photocatalytic hydrogen release rate to 6.85 mmol g-1 h-1. This work offers a facile way to enhance photocatalytic performance by controlling the size of metal nanoparticles on C3N4 precisely.