Plant polyphenol-involved coordination assembly-derived Mo3Co3C/Mo2C/Co@NC with phase regulation and interface engineering for efficient hydrogen evolution reaction electrocatalysis

Abstract

The rational exploration of highly active and low-cost materials for electrocatalytic hydrogen evolution is extremely imperative, but remains challenging as well. Transition metal carbides (TMCs) as highlighted electrocatalysts usually exhibit unsatisfactory activity and stability. In this work, we demonstrate a two-step strategy for electrocatalyst synthesis involving biomass-derived tannic acid (TA) and coordination assembly preparation followed by subsequent high-temperature carbonization. Interestingly, by simply controlling the feed amount of TA, heterostructured nitrogen-doped graphene-coated Mo₃Co₃C-based tri- and bi-component electrocatalysts (Mo₃Co₃C/Mo₂C/Co@NC and Mo₃Co₃C/Co@NC) can be obtained with phase regulation and interface engineering. It is observed that the heterostructured materials possess more active sites than that of the TMC-excluding sample (Co@NC). Moreover, the tri-component Mo₃Co₃C/Mo₂C/Co@NC may enhance the intrinsic activity at each active site due to the strong interaction at the Mo₃Co₃C/Mo₂C interface. These advantages allow the Mo₃Co₃C/Mo₂C/Co@NC catalyst to deliver superior electrocatalytic activity and favorable kinetics towards the HER, with a low overpotential of 211 mV and a Tafel slope of 96.0 mV dec⁻¹. Furthermore, it has good long-term stability. This work provides new inspiration for heterostructured TMC-based electrocatalysts with high performance towards promising catalytic applications.