β-Mo_2C/MoO_2 heterostructures for hydrogen evolution reaction: Morphology and catalytic activity regulated by heteroatom doping

摘要

Improving the activity of non-noble metallic electrocatalyst for hydrogen evolution reaction (HER) is an important issue for hydrogen energy utilization. In this work, we reported a new strategy for morphology regulation of beta-Mo2C/MoO2 heterostructure via heteroatom doping to enhance the electrocatalytic HER activity. Electron microscopy observations found that N and S doping resulted in nanosphere and nanorod morphology, respectively. Amongst the S doping catalyst (denoted as S@beta-Mo2C/MoO2) exhibited remarkably improved electrocatalytic HER activity and stability as compared to the pristine beta-Mo2C/MoO2 catalyst, whereas the N doping induced significant degradation of catalytic activity and stability. The mechanism investigations reveal that the nanorod morphology of S@beta-Mo2C/MoO2 endows it lower charge transfer resistance, higher electrochemical active surface area and lower valence state of Mo species, which contributes positively and importantly to its better electrocatalytic HER activity. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.