Facilitated Unidirectional Electron Transmission by Ru Nano Particulars Distribution on MXene Mo2C@g-C3N4 Heterostructures for Enhanced Photocatalytic H2 Evolution

Precious metals exhibit promising potential for the hydrogen evolution reaction (HER), but their limited abundance restricts widespread utilization. Loading precious metal nanoparticles (NPs) on 2D/2D heterojunctions has garnered considerable interest since it saves precious metal consumption and facilitates unidirectional electron transmission from semiconductors to active sites. In this study, Ru NPs loaded on MXenes Mo2C by an in-site simple strategy and then formed 2D/2D heterojunctions with 2D g-C3N4 (CN) via electrostatic self-assembly were used to enhance photocatalytic H2 evolution. Evident from energy band structure analyses such as UV-vis and TRPL, trace amounts of Ru NPs as active sites significantly improve the efficiency of the hydrogen evolution reaction. More interestingly, MXene Mo2C, as substrates for supporting Ru NPs, enriches photoexcited electrons from CN, thereby enhancing the unidirectional electron transmission. As a result, the combination of Ru-Mo2C and CN constructs a composite heterojunction (Ru-Mo2C@CN) that shows an improved H2 production rate at 1776.4 μmol∙g−1∙h−1 (AQE 3.58% at 400 nm), which is facilitated by the unidirectional photogenerated electron transmission from the valence band on CN to the active sites on Ru (CN→Mo2C→Ru). The study offers fresh perspectives on accelerated unidirectional photogenerated electron transmission and saved precious metal usage in photocatalytic systems.