Constructing stable charge redistribution through strong metal–support interaction for overall water splitting in acidic solution

Abstract

Designing bifunctional electrocatalysts with high activity and durability for overall water splitting in acid electrolytes is still a huge challenge because their excellent activity is difficult to maintain. Herein, a method to stabilize the charge redistribution on catalysts by constructing Pt–RuO₂@KB heterostructures with strong metal–support interactions is proposed first to achieve remarkable water splitting performance in acidic media. By performing X-ray photoelectron spectroscopy (XPS) before and after a 150 h long-time v–t test, it is found that the electron transfer from Pt to RuO₂ could form a stable charge redistribution. Benefiting from the Pt–RuO₂ heterostructures, the strong metal–support interaction (SMSI) between Pt–RuO₂ and KB as well as the stable charge redistribution between Pt and RuO₂, Pt–RuO₂@KB exhibits ultrahigh intrinsic activity (the turnover frequency (TOF) value is 34.5 s⁻¹ @ 300 mV for the oxygen evolution reaction (OER) and 20.2 s⁻¹ @ 100 mV for the hydrogen evolution reaction (HER), respectively) and outstanding overall water splitting performance (only needs 1.54 V at a current density of 10 mA cm⁻²). Notably, Pt–RuO₂@KB with the stable charge redistribution exhibits striking stability for overall water splitting; during a 150 h continuous v–t test, the voltage is maintained well without noticeable degradation in 0.1 M HClO₄. Density functional theory (DFT) calculations verify that the charge redistribution between Pt and RuO₂ can dramatically lower the water splitting barrier and raise the vacancy formation energy of atoms in the catalyst, which could effectively inhibit the dissolution of atoms in Pt–RuO₂@KB in an acidic medium and achieve superior water electrolysis performance.