One-Step Synthesis of Nb2O5/C/Nb2C (MXene) Composites and Their Use as Photocatalysts for Hydrogen Evolution

Hydrogen production through facile photocatalytic water splitting is regarded as a promising strategy to solve global energy problems. Transition-metal carbides (MXenes) have recently drawn attention as potential co-catalyst candidates for photocatalysts. Here, we report niobium pentoxide/carbon/niobium carbide (MXene) hybrid materials (Nb2O5/C/Nb2C) as photocatalysts for hydrogen evolution from water splitting. The Nb2O5/C/Nb2C composites were synthesized by one-step CO2 oxidation of Nb2CTx. Nb2O5 grew homogeneously on Nb2C after mild oxidation, during which some amorphous carbon was also formed. With an optimized oxidation time of 1.0 h, Nb2O5/C/Nb2C showed the highest hydrogen generation rate (7.81 mu mol h(-1) g(cat)(-1)), a value that was four times higher than that of pure Nb2O5. The enhanced performance of Nb2O5/C/Nb2C was attributed to intimate contact between Nb2O5 and conductive Nb2C and the separation of photogenerated charge carriers at the Nb2O5/Nb2C interface; the results presented herein show that transition-metal carbide are promising co-catalysts for photocatalytic hydrogen production.