Negatively charged platinum nanoparticles on dititanium oxide electride for ultra-durable electrocatalytic oxygen reduction

Abstract

Modulating metal–support interactions (MSIs) has been a rational approach to enhance the kinetics of supported Pt-based nanocatalysts for the oxygen reduction reaction (ORR). However, the sluggish activity and poor durability of the reduced Pt loadings on supporting materials remain challenging issues for a practical ORR. Here, we report negatively charged platinum nanoparticles (Pt NPs) supported by dititanium oxide electride ([Ti₂O]²⁺·2e⁻) for an ultra-durable electrocatalytic ORR, simultaneously exhibiting 89 and 31 times higher specific and mass activities to those of commercial Pt/C catalysts. MSI-induced spontaneous charge transfer from the [Ti₂O]²⁺·2e⁻ electride to Pt NPs forms negatively charged Pt NPs with surface-accumulated excess electrons. Both atomic-scale microscopic and spectroscopic measurements verify that the omniscient excess electrons on the catalyst completely suppress the formation of Pt–O skins in an alkaline medium. As a result, the catalyst demonstrates a sustainable performance with nearly 95% retention of the initial current density during continuous 350 hours of operation.