In Situ Active Site Refreshing of Electro-Catalytic Materials for Ultra-Durable Hydrogen Evolution at Elevated Current Density

Enhancing the durability of catalysts is of critical significance to industrialize green hydrogen production. Herein, a novel active site in situ refreshing strategy is proposed and demonstrated to fabricate highly active and ultra-durable hydrogen evolution reaction (HER) electro-catalytic material by HER activation. Briefly, a composite catalytic material is synthesized, which features Ni(PO₃)₂ active sites being embedded inside the amorphous Mo compound matrix (named NiMoO-P). The Mo compound matrix undergoes gradual dissolution during HER followed by a dynamic equilibrium between the dissolution and deposition of the amorphous matrix. This process promotes the continuous exposure of insoluble Ni(PO₃)₂ and Ni₂P partially converted from Ni (PO₃) ₂ in situ on the surface during HER activation. Thus, activated catalyst exhibits excellent HER performance featuring an extremely high current density of 1500 mA cm⁻² at a rather low overpotential of 340 mV, and more attractively, an ultra-long durability for hydrogen evolution for at least 1000 h at an industrial-applicable current density of 900 mA cm⁻². The mechanisms for the especially high HER performance are attributed to the exposure and continuous refreshing of Ni(PO₃)₂ and the in situ formed Ni₂P during the HER process based on the DFT calculations and quasi-in situ Raman spectroscopic monitoring.