Energy level engineering in transition-metal doped spinel-structured nanosheets for efficient overall water splitting

• Main Authors: Lai, Feili, Feng, Jianrui, Ye, Xiaobin, Zong, Wei, He, Guanjie, Miao, Yue-E, Han, Xuemei, Ling, Xing Yi, Parkin, Ivan P., Pan, Bicai, Sun, Yongfu, Liu, Tianxi
• Other Authors: School of Physical and Mathematical Sciences
• Format: Article
• Language: English
• Published: 2021
• Subjects: Science::Chemistry; Highly Efficient; Oxygen Evolution
• Online Access: https://hdl.handle.net/10356/151596
• Institution: Nanyang Technological University

Unraveling the role of transition-metal doping in affecting the native spinel-structured nanosheets' water splitting remains a grand challenge. In this work, a series of spinel-structured nanosheets wrapped hollow nitrogen-doped carbon polyhedrons were constructed, and doped transition-metal domains were deliberately introduced on the surface. Theoretical investigations show that their energy level can be finely tuned via direct transition-metal doping engineering. As a prototype, an Fe-doped NiCo₂O₄ nanosheets wrapped hollow nitrogen-doped carbon polyhedron (Fe–NiCo₂O₄@HNCP) exhibits outstanding bifunctional electrocatalytic performances with low overpotentials (η = 270 mV for OER, η = 84 mV for HER), low Tafel slopes (b = 42 mV dec⁻¹ for OER, b = 47 mV dec⁻¹ for HER), and high durability. The enhanced performance is attributed to the synergistic effects of energy level matching for electron transfer, and partial charge delocalization-induced rich active sites for reactant adsorption via thermodynamic and kinetic acceleration. This work may open a new pathway to design highly active and stable transition-metal doped electrocatalysts by manipulated energy levels for efficient overall water splitting.