Microdynamic modulation through Pt–O–Ni proton and electron “superhighway” for pH-universal hydrogen evolution

Abstract

Optimizing the microdynamics in alkaline and neutral conditions is a significant but challenging task in developing pH-universal hydrogen evolution (HER) electrocatalysts. Herein, a unique Pt–O–Ni bridge has been constructed to alter the coordination and electronic environment between Pt nanoparticles (Pt_n) and nickel metaphosphate (NPO) substrate (Pt-NPO). Sufficient electron transfer from NPO to Pt_n to maintain an electron-rich environment and a low valence state of Pt_n. Furthermore, H* is produced from the H₂O dissociation on Ni site and then spillover toward Pt sites to bind into H₂, which makes up for the insufficient H₂O dissociation ability of Pt in Volmer step. Pt-NPO exhibits long-term stability and only need the overpotentials of 22.3, 33.0 and 30.5 mV to attain 10 mA cm⁻² in alkaline, neutral and acidic media, respectively. The anion-exchange membrane (AEM) water electrolyzer catalyzed by Pt-NPO shows high water electrolysis performance that a cell voltage of 1.73 V is needed to obtain the current density of 500 mA cm⁻² in 1 M KOH at 80 °C, at the same time maintains good stability for 350 h. The regulation strategy proposed in this work is helpful for the design and synthesis of highly efficient pH-universal HER electrocatalysts.