Coupled cobalt-doped molybdenum carbide@N-doped carbon nanosheets/nanotubes supported on nickel foam as a binder-free electrode for overall water splitting

In an attempt to develop low-cost, non-noble-metal bifunctional electrocatalysts for water electrolysis in alkaline media, cobalt-doped molybdenum carbide@N-doped carbon nanosheets/nanotubes were fabricated by using C3N4 as the carbon source on a 3D porous nickel foam substrate. Benefiting from the optimized electronic structure and enhanced mass and charge transport, as well as the 3D conducting pathway, MoxCoy@N-CNSs/CNTs shows superior performance towards both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in an alkaline medium. The optimal electrocatalyst is Mo2Co1@N-CNSs/CNTs, which reveals a current density of 10 mA cm(-2) at the low overpotentials of 99 mV and 300 mV for the HER and OER, respectively, and a relatively low cell voltage (1.63 V) for the overall water electrolysis. The method of optimizing the composition and nanostructure of a material provides a new avenue for the development and utilization of high-performance electrocatalysts. (C) 2019, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.