Huang Zinan, He Liuqing, Zhang Wenbiao, Huang Wenjie, Mo Qijie, Yang Lichun, Fu Qiang, Gao Qingsheng
College of Chemistry and Materials Science, and Guangdong Provincial Key Laboratory of Functional Supramolecular Coordination Materials and Applications, Jinan University Guangzhou 510632, PR China.
School of Materials Science and Engineering, and Guangdong Provincial Key Laboratory of Advanced Energy Storage Materials, South China University of Technology, Guangzhou 510640, PR China.
J Colloid Interface Sci. 2022 Sep 15;622:728-737. doi: 10.1016/j.jcis.2022.04.150. Epub 2022 Apr 30.
Bi-functional electrocatalysts are desired for both hydrogen and oxygen evolution reactions (HER and OER). Herein, facile O-plasma activation is introduced to improve the bi-functionality via constructing nickel sulfide-oxide heterostructures. NiS-NiO supported by nickel foam delivers obviously elevated HER and OER activity in comparison with pristine NiS and recently reported NiS-based electrocatalysts, featured by the low overpotentials for HER (104 mV) and OER (241 mV) at ±10 mA cm in 1.0 M KOH, as well as a voltage of 1.52 V for overall water splitting. As revealed by in-situ Raman spectroscopy, on the one hand, Ni(OH) generated from NiS during alkaline HER accelerates water dissociation toward the gradually improved performance; on the other hand, this heterostructure undergoes extensive oxidation during OER, leading to excessive NiOOH covering on NiS and thereby declining activity. These changes are interpreted by the distinct thermodynamic relationship under specific electrochemical conditions via density functional theory calculations.
双功能电催化剂对于析氢反应（HER）和析氧反应（OER）都很有需求。在此，引入了简便的氧等离子体活化方法，通过构建硫化镍 - 氧化物异质结构来提高双功能性。由泡沫镍支撑的NiS - NiO与原始NiS以及最近报道的基于NiS的电催化剂相比，展现出明显提高的HER和OER活性，其特征在于在1.0 M KOH中，在±10 mA cm²时HER的过电位低（104 mV），OER的过电位低（241 mV），以及全水解电压为1.52 V。原位拉曼光谱表明，一方面，在碱性HER过程中由NiS生成的Ni(OH)₂加速了水的解离，从而使性能逐渐提高；另一方面，这种异质结构在OER过程中发生广泛氧化，导致过量的NiOOH覆盖在NiS上，从而降低活性。通过密度泛函理论计算，在特定电化学条件下的不同热力学关系解释了这些变化。
