Bottom‐up design of bimetallic cobalt–molybdenum carbides/oxides for overall water splitting

A rational bottom‐up design method gives access to bimetallic metal carbide/oxide nanoparticles deposited on N,P‐doped carbon matrices. The resulting composites show outstanding electrochemical reactivity for oxygen and hydrogen evolution and allow the assembly of an overall water‐splitting device. Earth‐abundant transition‐metal‐based catalysts for electrochemical water splitting are critical for sustainable energy schemes. In this work, we use a rational design method for the synthesis of ultrasmall and highly dispersed bimetallic CoMo carbide/oxide particles deposited on graphene oxide. Thermal conversion of the molecular precursors [H3PMo12O40], Co(OAc)2⋅4 H2O and melamine in the presence of graphene oxide gives the mixed carbide/oxide (Co6Mo6C2/Co2Mo3O8) nanoparticle composite deposited on highly dispersed, N,P‐doped carbon. The resulting composite shows outstanding electrocatalytic water‐splitting activity for both the oxygen evolution and hydrogen evolution reaction, and superior performance to reference samples including commercial 20 % Pt/C & IrO2. Electrochemical and other materials analyses indicate that Co6Mo6C2 is the main active phase in the composite, and the N,P‐doping of the carbon matrix increases the catalytic activity. The facile design could in principle be extended to multiple bimetallic catalyst classes by tuning of the molecular metal oxide precursor.
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