Constructing CoO/Mo2C Heterostructures with Interfacial Electron Redistribution Induced by Work Functions for Boosting Overall Water Splitting

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/Mo2C 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 Mo2C through the formed Co-CMo bond at the interface of CoO/Mo2C, 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/Mo2C 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/Mo2C 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.

Automated summary

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. In this study, an epitaxial heterojunction catalyst of CoO/Mo2C with interfacial electron redistribution induced by work functions is constructed for overall water splitting via a top-down strategy. The CoO/Mo2C catalyst exhibits excellent hydrogen evolution reaction (HER) catalytic activity with low overpotential and stability, as well as outstanding performance in overall water splitting. This work provides a novel possibility of designing materials based on interfacial effects arising from the built-in field for application in other fields.