WXy /g-C3 N4 (WXy =W2 C, WS2 , or W2 N) Composites for Highly Efficient Photocatalytic Water Splitting.

Abstract

The development of earth-abundant, economical, and efficient photocatalysts to boost water splitting is a key challenge for the practical large-scale application of hydrogen energy. In this study, g-C3 N4 loaded with different tungsten compounds (W2 C, WS2 , and W2 N) is found to exhibit enhanced photocatalytic activities. W2 C/g-C3 N4 displays the highest activity for the photocatalytic reaction with a H2 evolution rate of up to 98 μmol h-1 , as well as remarkable recycling stability. The excellent photocatalytic activity of W2 C/g-C4 N3 is attributed to the suitable band alignment in W2 C/g-C4 N3 and high HER activity of the W2 C cocatalyst, which promotes the separation and transfer of carriers and hydrogen evolution at the surface. These findings demonstrate that the tungsten carbide cocatalyst is more active for the photocatalytic reaction than the sulfide or nitride, paving a way for the design of novel and efficient carbides as cocatalysts for photocatalysis.