Multifunctional electrocatalyst PtM with low Pt loading and high activity towards hydrogen and oxygen electrode reactions: A computational study

Abstract

Multifunctional electrocatalysts (MFECs) for hydrogen evolution reaction (HER), oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) are highly desirable for the development of electrochemical systems including water electrolysis, fuel cells and metal–air batteries, which have been rarely reported to date. Despite the high activity of Platinum (Pt), the limited reserves and high price severely limit its wide application. Therefore, it is urgent to explore catalysts requiring minimal amounts of Pt but still active to function. In accordance to the typical experimental electrocatalytic conditions for Pt monolayer (PtM), in this work we first identify the atomic configuration of PtM and evaluate the electronic and electrocatalytic properties towards HER, OER and ORR. Density functional theory (DFT) investigations suggest that PtM exhibits a buckled structure (b-PtM) and holds great promise for low-Pt-loading and, interestingly, all-in-one electrocatalyst, which could be highly active towards HER, OER and ORR. Our results show that the excellent electrocatalytic activity mainly originates from the amounts of highly active catalytic sites and low theoretical HER/OER/ORR overpotentials, even lower than those of currently commercialized Pt. Remarkably, the significantly reduced reaction barriers on b-PtM elucidate the fast reaction kinetics reported in experiments. Therefore, this work may stimulate the development of PtM electrocatalyst for other key energy conversion processes including oxygen evolution reaction and further breakthroughs of low-Pt-loading electrocatalysts.