Constructing CoO/Mo<sub>2</sub>C Heterostructures with Interfacial Electron Redistribution Induced by Work Functions for Boosting Overall Water Splitting
Hanyang Chen, Lei Yang, Rongxu Wang, Wenjie Zhang, Rui Liu, Yu‐Zhe Yun, Nan Wang, Seeram Ramakrishna, Lifang Jiao, Yun‐Ze Long
Abstract
Abstract Space charge transfer of heterostructures driven by the work‐function‐induced built‐in field can regulate the electronic structure of catalysts and boost the catalytic activity. Herein, an epitaxial heterojunction catalyst of CoO/Mo 2 C with interfacial electron redistribution induced by work functions (WFs) is constructed for overall water splitting via a novel top‐down strategy. Theoretical simulations and experimental results unveil that the WFs‐induced built‐in field facilitates the electron transfer from CoO to Mo 2 C through the formed “Co─C─Mo” bond at the interface of CoO/Mo 2 C, achieving interfacial electron redistribution, further optimizing the Gibbs free energy of primitive reaction step and then accelerating kinetics of hydrogen evolution reaction (HER). As expected, the CoO/Mo 2 C with interfacial effects exhibits excellent HER catalytic activity with only needing the overpotential of 107 mV to achieve 10 mA cm −2 and stability for a 60‐h continuous catalyzing. Besides, the assembled CoO/Mo 2 C behaves the outstanding performance toward overall water splitting (1.58 V for 10 mA cm −2 ). This work provides a novel possibility of designing materials based on interfacial effects arising from the built‐in field for application in other fields.