image: Compared with pure NC, the introduction of VN induces the electron transfer from the N on NC to the V in VN and makes the N on NC electrophilic. An increased electrophilicity on the surface of NC promotes the ORR progress. view more
Credit: ©Science China Press
This study is led by Dr. Liang Zhou (State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan, 430070, China) and Dr. Yan Zhao (State Key Laboratory of Silicate Materials for Architectures, International School of Materials Science and Engineering, Wuhan University of Technology, Wuhan, 430070, China; The Institute of Technological Sciences, Wuhan University, Wuhan, 430072, China). The team optimizes the electronic structure of the NC surface by introducing VN and founds that enhancing the electrophilicity of nitrogen atoms can promote the ORR progress.
In this study, a novel VN@NC nanocomposite consisting of a vanadium nitride (VN) nanoparticle core and chainmail-like NC shell has been constructed via a simple physical mixing and annealing process. Benefiting from the unique core@shell nanowire structure and modulated electronic structure, the as-prepared VN@NC manifests an obviously promoted ORR activity (onset potential: 0.93 V) compared to pure NC and bulk VN. Specifically, incorporating VN induces charge transfer from N on NC to V in VN and increases the electrophilicity of N on NC, resulting in optimized adsorption to O-containing intermediates. VN@NC also manifests decent long-term stability (89% current density retention after a 40000-s test). This finding highlights the significance of regulating the electronic structure of N in NC and provides a reliable strategy for constructing NC-based hybrid electrocatalysts.
See the article:
Improving the electrophilicity of nitrogen on nitrogen-doped carbon triggers oxygen reduction by introducing covalent vanadium nitride
https://doi.org/10.1007/s40843-022-2116-3
Journal
Science China Materials