Polarization Manipulation of NiO Nanosheets Engineered with Fe/Pt Single Atoms for High-Performance Electrocatalytic Overall Alkaline Seawater Splitting

Abstract

Regulating the metal–support interaction is recognized as an effective approach to modulating the electronic structure of single-atom catalysts. Here, we put forward a strategy to modulate the anchored metallic single atoms by manipulating the surface polarization of the support, which is demonstrated to be effective in designing alkaline seawater electrocatalysts. Specifically, we introduce Mn doping in weak-polarized NiO nanosheets to modulate its surface polarization and thereby regulate the electronic metal–support interaction between anchored Pt/Fe single atoms and NiO support. The optimized Pt1/Mn_NiO||Fe1/Mn_NiO electrode pair exhibits superior overall alkaline seawater-splitting performance, achieving an impressive low cell voltage of 1.44 V at a current density of 10 mA cm–2. The experimental characterizations and theoretical calculations highlight the significance of Mn doping in the surface polarization regulation of NiO. Moreover, the charge redistributions and the changes in coordination structure induced by Mn doping in Pt1/Mn_NiO and Fe1/Mn_NiO account for the decreased Gibbs free energy for the rate-determining steps in the HER and oxygen evolution reaction processes. This work demonstrates an effective method to design efficient alkaline seawater electrocatalysts by modulating electronic metal–support interaction over surface polarization regulation.