Nitrogen-doped carbon wrapped Co-Mo2C dual Mott–Schottky nanosheets with large porosity for efficient water electrolysis

Abstract

Efficient, inexpensive and stable electrocatalysts are challenging and desperately required in order to complement the water electrolysis of noble metal catalysts. Herein, a porous nitrogen-doped carbon wrapped Co-Mo₂C dual Mott–Schottky heterostructure has been successfully fabricated by carbonization of Co-Zn bimetal metal-organic framework (MOF) for water electrolysis. The heterostructure is found to feature with Co and Mo₂C nanoparticles uniformly encapsulated in the highly porous leaf-like N-doped carbon nanosheet matrix. Such a thin porous dual-Mott–Schottky configuration can afford abundant surface active sites and the boosted electron transfer to promote the water splitting. As for hydrogen/oxygen evolution reaction (HER/OER), it has demonstrated fast kinetics and low overpotentials of 92 mV (HER) and 338 mV (OER) at a current density of 10 mA cm⁻² in 1 M KOH. Furthermore, the overall water splitting is stably delivered with a low cell voltage of 1.68 V at 10 mA cm^-2 in 1 M KOH. Density function theory (DFT) calculations demonstrate that the interface correlation is favorable to water transfer by electron and speeds up adsorption and water dissociation. The work here opens up interesting possibilities for the rational design and innovation of MOF derived Mott–Schottky electrocatalysts for highly efficient water electrolysis.