Efficient electrocatalytic reactions require a coordinated active center that may provide a properly reaction intermediates adsorption in water splitting. Herein, a Ni active center coordination reconstruction method achieved by multidimensional modulation of phase transition, iodine coordination, and vacancy defects is designed and implemented. This coordination reconstruction results in the successful synthesis of Ni5 P4- x Ix /Ni2 P nanocorals that show outstanding bifunctional catalytic activity due to deep optimization of the adsorption energy. The overpotentials of hydrogen evolution reaction and oxygen evolution reaction at 10 mA cm-2 are 46 and 163 mV, respectively. Only 1.46 V is required to drive alkaline overall water splitting. Novel coordination environment is investigated by electron paramagnetic resonance spectroscopy and extended X-ray absorption fine structure spectroscopy. A 4D integrated material design strategy of "thermodynamic stability-electronic properties-charge transfer-adsorption energy" for water-splitting catalysts is proposed. This coordination reconstruction concept and material design method provide new perspectives for the research of novel catalysts.
Keywords: Ni center; coordination reconstruction; electrocatalyst; nanocoral structures; overall water splitting.
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