Searching for Pt-free hydrogen evolution reaction (HER) electrocatalysts based on low-cost and eartha-bundant materials is a crucial task for hydrogen-based energy industry. In this work, we demonstrate the one-step facile preparation of MoP nanosheets supported on carbon flake via a solid-state reaction with the use of (NH4)(6)Mo7O24 center dot 4H(2)O, NaH2PO4 center dot 2H(2)O and a biomass, sodium alginate, as Mo, P and C sources, respectively. When used as a novel HER electrocatalyst, such composites are excellent in activity and durability in acidic electrolytes. Moreover, they are also active in neutral electrolytes. (C) 2014 Elsevier B.V. All rights reserved.