Catalyst has been a bottleneck in hydrogen evolution reaction (HER) - a half reaction of water splitting. Hitherto the most efficient HER catalyst in terms of catalytic capacity remains to be those platinum group metals, especially platinum; however, rare metals' exorbitant cost and scarcity inhibit their further application in industry, which therefore call for catalysts prepared from earth-abundant elements. Herein, we introduce nickel phosphide nanospheres (NPNs) bearing excellent HER activity. Prepared via a facile, inexpensive, and eco-friendly preparation procedure, the as-synthesized NPNs have perfect over-potential to reach -100 mA/cm(2) (eta(100)), with eta(100) aching 251 mV in 0.5 M H2SO4. A series of durability tests, including cyclic voltammetry (CV) and chronoamperometry, also indicate NPNs' favorable stability under both acidic and alkaline conditions. After taking account of a string of factors, including NPNs' mass density, handy preparation process, superior catalytic activity as well as favorable durability, the NPNs bear probable potentiality of taking traditional noble metals' place as the HER catalyst and are worth studying further. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.