Generation of oxygen vacancies in NiFe LDH electrocatalysts by ultrasound for enhancing the activity toward oxygen evolution reaction
Xiumin Li, Qianyu Hu, Yazhou Xu, Xiaoyang Liang, Jiawei Feng, Kunyan Zhao, Guoqing Guan, Yongchao Jiang, Xiaogang Hao, Keyong Tang
Abstract
Introduction of vacancies is a promising route to enhance the performance of electrocatalysts by tuning the electronic structure and bonding energy. Here, the influence of ultrasound treatment on the O vacancies formation and interlayer spacing in NiFe layered double hydroxide (LDH) was investigated. It is found that the strong ultrasound treatment results in rich O vacancies on the surface of NiFe LDH, which affect the electrocatalysis performance. Besides, the ultrasound treated NiFe LDH electrocatalysts had a reduced thickness with a hexagonal nanosheet morphology and expanded interlayer distance, which could promote the diffusion of reactant and generated gas. When the obtained defect-rich NiFe LDH electrocatalyst prepared by a 10-min ultrasonic treatment was applied to catalyze oxygen evolution reaction (OER), only 194 mV of overpotential was needed to maintain a current density of 10 mA·cm−2.