Bifunctional Heterostructure Assembly of NiFe LDH Nanosheets on NiCoP Nanowires for Highly Efficient and Stable Overall Water Splitting

• Published in: Advanced functional materials 2018-04, Vol.28 (14), p.n/a
• Main Authors: Zhang, Haojie, Li, Xiaopeng, Hähnel, Angelika, Naumann, Volker, Lin, Chao, Azimi, Sara, Schweizer, Stefan L., Maijenburg, A. Wouter, Wehrspohn, Ralf B.
• Format: Article
• Language: English
• Subjects: bifunctional electrocatalysts; Electrocatalysts; Electrochemical impedance spectroscopy; Electrodes; Electrolysis; hydrogen evolution reaction (HER); Hydrogen evolution reactions; Interface stability; Intermetallic compounds; Iron compounds; Materials science; Metal foams; metal phosphide; Nanosheets; Nanowires; Nickel compounds; oxygen evolution reaction (OER); Oxygen evolution reactions; Structural stability; Synergistic effect; Water splitting
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.201706847

3D hierarchical heterostructure NiFe LDH@NiCoP/NF electrodes are prepared successfully on nickel foam with special interface engineering and synergistic effects. This research finds that the as‐prepared NiFe LDH@NiCoP/NF electrodes have a more sophisticated inner structure and intensive interface than a simple physical mixture. The NiFe LDH@NiCoP/NF electrodes require an overpotential as low as 120 and 220 mV to deliver 10 mA cm−2 for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in 1 m KOH, respectively. Tafel and electrochemical impedance spectroscopy further reveal a favorable kinetic during electrolysis. Specifically, the NiFe LDH@NiCoP/NF electrodes are simultaneously used as cathode and anode for overall water splitting, which requires a cell voltage of 1.57 V at 10 mA cm−2. Furthermore, the synergistic effect of the heterostructure improves the structural stability and promotes the generation of active phases during HER and OER, resulting in excellent stability over 100 h of continuous operation. Moreover, the strategy and interface engineering of the introduced heterostructure can also be used to prepare other bifunctional and cost‐efficient electrocatalysts for various applications. As‐synthesized NiFe layered double hydroxide (LDH)@NiCoP/Nickel foam (NF) electrodes exhibit excellent activity and stability for both hydrogen evolution reaction and oxygen evolution reaction owing to special interface engineering and synergistic effects. It is further used for overall water splitting with a cell voltage of 1.57 V and an outstanding stability for 100 h.