Herein, PVA-Mo2C/Mo2N nanospheres with surface roughness are synthesized via a polyvinyl alcohol (PVA) involved approach and used for hydrogen evolution reaction (HER). The average crystallite size of the PVA protected nMo(2)CN nanospheres (6.1 nm) is one third of that of the PVA-Mo2C/Mo2N without PVA protection (17.9 nm). At 10 mAcm(-2) current density, the as-synthesized PVA-Mo2C/Mo2N nanospheres with surface roughness exhibit HER overpotentials of 132 mV and 142 mV with corresponding Tafel slope of 51.8 mV dec(-1) and 50.4 mV dec(-1) in acid and alkaline medium, respectively. This high apparent activity can be attributed to the high intrinsic activity originated from the adjacent surface active sites of Mo2C and Mo2N as well as the large ECSA of PVA-Mo2C/Mo2N nanospheres with surface roughness. (C) 2018 Elsevier Ltd. All rights reserved.