Interfacing Co3Mo with CoMoOx for synergistically boosting electrocatalytic hydrogen and oxygen evolution reactions

Constructing strong coupling interface of metal and metal oxides is of great significance to design high-efficiency and stable bifunctional electrocatalysts for water splitting. In this work, an integrated electrode comprising of Co3Mo nanoalloys and porous CoO/Co2Mo3O8 hybrid nanosheets (Co3Mo/CoMoOx) was developed via a facile topological transformation by directly annealing of CoMoO4 under H2 atmosphere. This topological transformation endows the resultant Co3Mo/CoMoOx heterostructures with abundant and strong coupling interfaces, which could synergistically strengthen the conductivity of the catalyst and accelerate the charge transfer kinetics. Benefiting from the unique heterostructure and synergy among the different domains, the optimized Co3Mo/CoMoOx exhibits promising HER and OER performance with overpotentials of 26 and 256 mV at 10 mA cm−2, respectively. Furthermore, as-assembled Co3Mo/CoMoOx||Co3Mo/CoMoOx possesses a cell voltage of 1.54 V at 10 mA cm−2 in alkaline solution, which is preferable to many other reported bifunctional catalysts. This work shed a light on the design of efficient integrated bifunctional electrocatalyst by synergistically coupling of CoMo-based alloys with metal oxides.