In Situ Growth and Dynamic Transformation of Nickel Chelate Nanoarrays into Reactive Surface Reconstituted Heterostructure for Overall Water Splitting

Abstract In this work, self‐derivation and surface reconstruction strategies are innovatively introduced into the synthetic route of the metal complex‐derived catalysts. The in situ grown nanorod arrays of Ni‐based complex are prepared by a simple self‐derivation and rapid ligand chelation reaction. Furthermore, highly active heterogeneous electrocatalysts are developed by mild‐temperature calcination. Attributed to the maintained morphology and highly dispersed Ni/Ni(OH)₂ heterojunction active sites, the as‐prepared electrode exhibits superior hydrogen evolution activity (38.4 mV–10 mA cm⁻²). In particular, the dynamic reconstruction during oxygen evolution through in situ Fourier transform infrared and in situ Raman spectroscopies are observed. The reconstructed Ni(OH)₂/NiOOH by activation gives the electrode higher oxygen evolution performance (369 mV–200 mA cm⁻²). Further density functional theory mechanism studies disclose that Ni/Ni(OH)₂ contributes to the adsorption of H* in hydrogen evolution and the activated Ni(OH)₂/NiOOH optimizes the formation of intermediates in oxygen evolution.