Ultrafine WC1-x Nanocrystals: An Efficient Cocatalyst for the Significant Enhancement of Photocatalytic Hydrogen Evolution on g-C3N4

Developing noble metal-free, inexpensive, and highly active cocatalysts to increase the photocatalytic activity of photo catalysts and promote the practical application is significantly important. In this work, ultrafine carbon-deficient tungsten carbide (WC1-x) nanocrystals with an average size of 1.98 +/- 0.29 nm are successfully prepared as cocatalysts to dramatically enhance the photocatalytic activity of graphitic carbon nitride (g-C3N4). The optimized system (WC(1-x)CN5) exhibits the best photocatalytic H-2 production rate of 124.5 mu mol h(-1) (2490 mu mol h(-1) g(-1)), which is about 56 times that of bare g-C3N4. In this system, ultrafine WC1-x nanocrystals play a multifunctional role: effectively boosting the carrier separation and transfer and providing rich active sites for production. Hence, the loading of WC1-x nanocrystals remarkably increases the photocatalytic H-2 production activity of g-C3N4. This work demonstrates that ultrafine WC1-x nanocrystals have practical application potential to enhance photocatalytic H-2 evolution of g-C3N4.