Identifying the electrocatalytic sites of nickel disulfide in alkaline hydrogen evolution reaction

• DOI: 10.1016/j.nanoen.2017.09.036
• Publication Date: 2017-09-20T06:01:32Z
• Authors: Qiuyu Ma; Chengyi Hu; Kunlong Liu; Sung-Fu Hung; Daohui Ou; Hao Ming Chen; Gang Fu; Nanfeng Zheng
• Keywords: 7. Clean energy; 01 natural sciences; 0104 chemical sciences

Abstract Transition-metal chalcogenides have attracted great attention for their superior catalytic activity towards hydrogen evolution reaction (HER) as an alternative to platinum. Here we report a facile method for synthesizing two-dimensional nickel disulfide (NiS 2 ) by using Ni(OH) 2 on nickel foam as substrate. The as-synthesized NiS 2 displayed an activation period during HER with a remarkable structural and compositional change under alkaline conditions. Electrochemical in situ X-ray absorption spectroscopy revealed that metallic Ni acted as catalytic active species with superior activity of 67 mV to reach 10 mA cm −2 . The in situ generated metallic Ni were easily oxidized to large-area ultrathin Ni(OH) 2 when exposed to air. The overall water splitting device was fabricated by using NiS 2 -derived metallic Ni and Fe doped NiS 2 -derived hydroxide as HER and OER electrode with a potential of 1.52 V to reach 10 mA cm −2 .