One-Step Synthesis of Nb O /C/Nb C (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 (Nb O /C/Nb C) as photocatalysts for hydrogen evolution from water splitting. The Nb O /C/Nb C composites were synthesized by one-step CO oxidation of Nb CT . Nb O grew homogeneously on Nb C after mild oxidation, during which some amorphous carbon was also formed. With an optimized oxidation time of 1.0 h, Nb O /C/Nb C showed the highest hydrogen generation rate (7.81 μmol h  g ), a value that was four times higher than that of pure Nb O . The enhanced performance of Nb O /C/Nb C was attributed to intimate contact between Nb O and conductive Nb C and the separation of photogenerated charge carriers at the Nb O /Nb C interface; the results presented herein show that transition-metal carbide are promising co-catalysts for photocatalytic hydrogen production.