Anchoring of 2D CdS on Nb2CTX MXene nanosheets for boosting photocatalytic H2 evolution

To produce high energy density, clean hydrogen fuel by photocatalytic water splitting has become one of the important strategies for solving the shortage of fossil fuels in the future, so it is of great significance to improve photocatalytic performance. MXene with high conductivity and layered nanostructure is an excellent charge transport layer material, which can effectively enhance the photocatalytic performance of composites. Here, a novel 2D CdS/2D Nb2CTX composite was successfully prepared by a combination of electrostatic self-assembly and solvothermal reaction. The addition of Nb2CTX greatly hinders the agglomeration of CdS nanosheets, and the optimized CdS/Nb2CTX-40 composite presents a high photocatalytic H2 evolution rate of 5040 μmol/g/h, which is 4.3 times higher than that of pristine CdS nanosheets. In particular, the formation of Schottky heterojunction leads to a significant redistribution of charges on the CdS/Nb2CTX composite, which can accelerate the photo-generated charge separation and transfer of CdS nanosheets, allowing more photo-generated electrons to drive the water splitting reaction. Moreover, the photoelectrochemical measurements, electron spin resonance (ESR) detection and the first-principles calculations confirm the effective charge transfer and more active free radicals of the CdS/Nb2CTx composite.