Rational design of perfect interface coupling to boost electrocatalytical oxygen reduction

Abstract

Abstract The rational design and preparation of efficient Pt-based electrocatalysts towards the oxygen reduction reaction (ORR) is a key issue for the widespread application of hydrogen fuel cells. Despite many Pt/support hybrid materials that have been reported as promising electrocatalysts for the ORR, precisely controlling the contact facet between the Pt and the support has never been demonstrated to mediate the ORR. Herein, based on theoretical calculations, we constructed an interesting Pt/support electrocatalyst by chemically coupling Pt nanoparticles (NPs) with single crystal (Sc) LiTiO2 nano-octahedra (Pt NPs/Sc-LiTiO2) for the first time. Specifically, the Pt {111} atomic crystal planes are in contact with the highly lattice-matched Sc-LiTiO2 {111} crystal planes to form specific crystal-plane coupling heterostructures, leading to strong cooperative effects between the Sc-LiTiO2 and the Pt as well as to the epitaxial growth and favorable exposed facets of Pt on the surface of Sc-LiTiO2. These key features endow Pt NPs/Sc-LiTiO2 with a mass activity of 1.44 A mg−1Pt and specific activity of 1.78 mA cm− 2 at 0.9 V, which are 8.0 and 7.1-fold higher than those of the state-of-the-art Pt/C, respectively. Meanwhile, it can undergo 20000 sweep cycles with negligible activity decay and no obvious changes in morphology or composition, showing excellent ORR durability. The resulting ORR performance is also comparable to or even better than those of most first-class Pt-based electrocatalysts. Our synthetic strategy could be easily extended to the design and fabrication of other robust metal/support electrocatalysts.