Department of Inorganic and Physical Chemistry, Indian Institute of Science , Bangalore 560012, India.
ACS Appl Mater Interfaces. 2017 Jun 14;9(23):19746-19755. doi: 10.1021/acsami.6b15399. Epub 2017 May 31.
A novel Ni-Co-S-based material prepared by the potentiodynamic deposition from an aqueous solution containing Ni, Co, and thiourea is studied as an electrocatalyst for the hydrogen evolution reaction (HER) in a neutral phosphate solution. The composition of the catalyst and the HER activity are tuned by varying the ratio of the concentrations of Ni and Co ions in the electrolytes. Under optimized deposition conditions, the bimetallic Ni-Co-S exhibits higher electrocatalytic activity than its monometallic counterparts. The Ni-Co-S catalyst requires an overpotential of 150 mV for the HER onset, and 10 mA cm current density is obtained at 280 mV overpotential. The catalyst exhibits two different Tafel slopes (93 and 70 mV dec) indicating two dissimilar mechanisms. It is proposed that the catalyst comprises two types of catalytic active sites, and they contribute selectively toward HER in different potential regions.
一种新型的 Ni-Co-S 基材料是通过在含有 Ni、Co 和硫脲的水溶液中进行动电位沉积制备的，被用作中性磷酸盐溶液中析氢反应（HER）的电催化剂。通过改变电解液中 Ni 和 Co 离子浓度的比值来调整催化剂的组成和 HER 活性。在优化的沉积条件下，双金属 Ni-Co-S 表现出比其单金属对应物更高的电催化活性。Ni-Co-S 催化剂的 HER 起始过电势为 150 mV，在 280 mV 的过电势下，电流密度为 10 mA cm。该催化剂表现出两种不同的塔菲尔斜率（93 和 70 mV dec），表明存在两种不同的机制。据推测，该催化剂包含两种类型的催化活性位点，它们在不同的电位区域对 HER 有选择性贡献。
