Self-supported NiFe-LDH nanosheets on NiMo-based nanorods as high-performance bifunctional electrocatalysts for overall water splitting at industrial-level current densities
Yan Zhang, Biao Feng, Minglei Yan, Zhen Shen, Yiqun Chen, Jingyi Tian, Fengfei Xu, Guanghai Chen, Xizhang Wang, Lijun Yang, Qiang Wu, Zheng Hu
Abstract
Efficient, durable and economic electrocatalysts are crucial for commercializing water electrolysis technology. Herein, we report an advanced bifunctional electrocatalyst for alkaline water splitting by growing NiFe-layered double hydroxide (NiFe-LDH) nanosheet arrays on the conductive NiMo-based nanorods deposited on Ni foam to form a three-dimensional (3D) architecture, which exhibits exceptional performances for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). In overall water splitting, only the low operation voltages of 1.45/1.61 V are required to reach the current density of 10/500 mA·cm−2, and the continuous water splitting at an industrial-level current density of 500 mA·cm−2 shows a negligible degradation (1.8%) of the cell voltage over 1000 h. The outstanding performance is ascribed to the synergism of the HER-active NiMo-based nanorods and the OER-active NiFe-LDH nanosheet arrays of the hybridized 3D architecture. Specifically, the dense NiFe-LDH nanosheet arrays enhance the local pH on cathode by retarding OH− diffusion and enlarge the electrochemically active surface area on anode, while the conductive NiMo-based nanorods on Ni foam much decrease the charge-transfer resistances of both electrodes. This study provides an efficient strategy to explore advanced bifunctional electrocatalysts for overall water splitting by rationally hybridizing HER- and OER-active components.