Interfacing RuO2 with Pt to induce efficient charge transfer from Pt to RuO2 for highly efficient and stable oxygen evolution in acidic media

Abstract

The oxygen evolution reaction (OER) requires a large overpotential which undermines the stability of electrocatalysts, typically IrO_x or RuO_x. RuO_x is particularly vulnerable to high overpotential in acidic media, due to the formation of soluble species, thus making it nearly impossible to be used as a commercially viable OER electrocatalyst. Herein, we demonstrate that the charge transfer from Pt to conjoined RuO₂ dramatically stabilizes the RuO₂ phase against overoxidation, the main culprit of disintegration of RuO₂. In this work, we compared the OER performance of three different types of Au@Pt@RuO_x nanowires, namely, hetero-interfaced, gradient-alloy, and conformal-shell type, with varying degrees of interaction between Pt and RuO₂. Among the studied samples, the hetero-interfaced type exhibited the highest OER mass activity of 1.311 A mg_Ru⁻¹ at 1.48 V_RHE and maintained its activity durably, thus demonstrating the effectiveness of charge transfer from Pt to RuO₂ in the hetero-interfaced structure against overoxidation of RuO₂.