First principles calculations were performed to systematically investigate the surface relaxation, surface stability, electronic structure of the pyrite NiS2. The results demonstrate that the stable order of the surface energy is (1 0 0) > (1 1 0) > (1 11). The adsorption of K, Na, Mo, Mg, Ca, O, F, Br, Cl or I element can stabilize the three planes through lowering their surface energies. The (1 0 0) surface energy decreases firstly and then increases with Mo coverage Theta, guiding to synthesize NiS2 nanocubes. Experimentally, uniform NiS2 nanocubes with the length of 200 nm were synthesized by using moderate sodium molybdate as a purposive mineralizer through a simple hydrothermal method on the base of theoretical prediction. The present investigation of the morphology and structure of NiS2 nanocubes provides insight into the crystal controlled growth and applications of the surface chemistry of NiS2. (C) 2017 Elsevier B.V. All rights reserved.