Dynamic Surface Pre-reconstruction and Selenization Co-regulate the Electronic Structure of the Central Metal Ni and Promote the Efficient Water-splitting

Abstract

In the oxygen evolution reaction (OER), it is discovered that introducing defects into Ni-based electrocatalysts can effectively enhance their catalytic activity. However, the specific structure of these defects and their role in modulating the performance of electrocatalysts remain unclear. Herein, an innovative core-shell nano-heterogeneous catalyst is reported that significantly boosts water decomposition efficiency through a strategy combining dynamic surface pre-reconfiguration and selenization. The Ni₃Mo-reconstruction@MoSe₂/NiSe₂ (NM-Re@MS/NS) core-shell heterogeneous catalyst is designed and synthesized. The surface pre-reconstruction technique is employed to adjust the element distribution and induce the catalyst to form a more active surface phase. The MoSe₂/NiSe₂ (MS/NS) modulates the electronic structure and surface chemistry of the catalyst, thereby facilitating the adsorption/desorption of OH⁻ and *H. As anticipated, NM-Re@MS/NS exhibited excellent catalytic activity for both the OER and hydrogen evolution reaction (HER) in 1.0 M KOH (OER: 258 mV@300 mA cm⁻²; HER: 65 mV@10 mA cm⁻²), with notable stability (OER: 80 h@250 mA cm⁻²; HER: 63h@250 mA cm⁻²). Importantly, in OER || HER system, the NM-Re@MS/NS catalyst, acting as both cathode and anode, exhibits an overpotential of 284 mV at 300 mA cm⁻², significantly increasing the rates of hydrogen and oxygen production.