Engineering highly active Ag/Nb2O5@Nb2CTx (MXene) photocatalysts via steering charge kinetics strategy

Steering charge kinetics is one of the most urgent unsolved issues in photocatalysis. The effective spatial separation of photogenerated electron-hole pairs is particularly important in the design and controllable preparation of nano-photocatalysts. Herein, one-dimensional Nb2O5 nanorod arrays with [001] orientation were grown insitu on two-dimensional Nb2CTx MXenes through a facile hydrothermal method for the first time. Ag nanoparticles were then photodeposited on the Nb2O5 nanorods to form hierarchical 0D/1D/2D nanohybrids. It was experimentally demonstrated that -OH is predominantly adsorbed on Nb2CTx as termination groups, which resulted in a low work function (2.7 eV). Thanks to the unique structure, the highly active [0 01] Nb2O5 nanorods afford high-efficiency photogeneration of electron-hole pairs, while the low-work-function -OH terminated Nb2CTx allows for trapping holes, and Ag nanoparticles act as electron reservoir and sites of hydrogen evolution reaction (HER). The ternary Ag/Nb2O5@Nb2CTx nanohybrids reached a record HER activity (682.2 and 824.2 mu mol center dot g-1h- 1 use methanol and glycerol as sacrificial agents, respectively) among the niobium-based photocatalysts, demonstrating the potential of MXenes as a platform for the synthesis of high-performance heterojunction structures, where the tunable electronic property is a key factor.

Automated summary

Steering charge kinetics is crucial in photocatalysis. In this study, Nb2O5 nanorods were grown on Nb2CTx MXenes, forming hierarchical nanohybrids with excellent photocatalytic performance, showcasing the potential of MXenes for high-performance heterojunction structures.