Vertically standing MoP nanosheet arrays on Mo substrate: An integrated binder-free electrode for highly efficient and stable hydrogen evolution

Although electrochemical water splitting provides an environmentally friendly route for the generation of hydrogen energy, the development of cost-effective, active and durable electrocatalysts for hydrogen evolution reaction has still been a great challenge. Here we report the large-scale synthesis of vertically standing MoP nanosheet arrays on Mo substrate topotactically converted from its MoS2 counterparts through phosphorization. Under optimal conditions, the obtained MoP nanosheet arrays not only have high specific surface area and fully exposed active sites, but also possess excellent structural robustness. As a binder-free, integrated and self-supported hydrogen evolution reaction electrode, the MoP nanosheet arrays exhibit outstanding catalytic activity, which need only an overpotential of 95 and 106 mV to drive 10 mA cm(-2) of current in 0.5 M H2SO4 and 1 M KOH, respectively, and present correspondingly a relatively small Tafel slope of 50.0 and 56.0 mV.dec(-1). Moreover, the MoP nanosheet arrays possess superior hydrogen evolution reaction durability and strong tolerance to the corresponding working environments. Thus, our work offers a simple and viable strategy of fabricating highly efficient hydrogen evolution reaction electrode in large scale for electrochemical water-splitting. (C) 2019 Published by Elsevier B.V.