Developing efficient and robust free-standing electrocatalysts for overall water splitting is a promising but challenging task. Herein, the N-incorporated Ni nanosheets non-fully encapsulated by N-doped carbon (NC) layer are fabricated (N─Ni©NC). The introduction of N not only regulates the size of nanosheets in N─Ni©NC but also promotes the electrochemical activity of metal Ni. Experimental and theoretical results reveal that strong bonding of the lattice N activates the inert metal Ni by promoting charge transfer between Ni and N. In addition, the upward shift of the d-band center induced by lattice N enhances the adsorption of intermediates, thereby making Ni as a new OER active site together with C. This strategy of generating Ni and C dual active sites by introducing lattice N greatly accelerates oxygen evolution reaction (OER) kinetics, resulting in excellent electrocatalytic performance of N─Ni©NC. At the current density of 10 mA cm-2, the overpotentials of hydrogen evolution reaction (HER) and OER are 27 and 206 mV, respectively, and the cell voltage for overall water splitting only needs 1.47 V. This work offers a unique heteroatom activation approach for designing free-standing electrodes with high activity.
Keywords: Ni activation; N─Ni©NC; lattice N; overall water splitting; strong bonding.
© 2024 The Author(s). Advanced Science published by Wiley‐VCH GmbH.