Anti-Corrosive SnS2/SnO2 Heterostructured Support for Pt Nanoparticles Enables Remarkable Oxygen Reduction Catalysis via Interfacial Enhancement

The stability of Pt-based catalysts for oxygen reduction reaction (ORR) in hydrogen fuel cells is seriously handicapped by the corrosion of their carbon supports at high potentials and acidic environments. Herein, a novel SnS2/SnO2 hetero-structured support is reported for Pt nanoparticles (NPs) as the ORR catalyst, where Pt NPs are mainly deposited at the interfaces of SnS2 and SnO2 moieties. The Pt-support interactions, which can be tuned by the concentration of the heterointerfaces, can accelerate the electronic transfer and enrich the electron density of Pt with a favorable shift of the d-band center. In electrochemical measurements, the ORR mass activity (MA) of the optimal Pt-SnS2/SnO2 catalyst at 0.9 V versus RHE (0.40 A mg(Pt)(-1)) is four times higher than that of Pt/C. As for the stability, the electrochemical active surface area and MA of Pt-SnS2/SnO2 are only decreased by 18.2% and 23.7% after 50 000 potential cycles at a high potential region (1.0-1.6 V), representing the best ORR stability among the reported Pt-based catalysts. Density functional theory calculations indicate that the binding energy and migration barrier of Pt atom/cluster on the SnS2/SnO2 heterojunction are much higher relative to other supports, accounting for the outstanding stability of the catalyst.

Automated summary

A novel SnS2/SnO2 hetero-structured support is reported for Pt nanoparticles as the oxygen reduction reaction (ORR) catalyst, with Pt NPs mainly deposited at the interfaces of SnS2 and SnO2 moieties. The Pt-support interactions, tuned by the concentration of the heterointerfaces, enhance electronic transfer and enrich electron density of Pt, resulting in improved ORR activity and stability. Density functional theory calculations reveal the higher binding energy and migration barrier of Pt on the SnS2/SnO2 heterojunction, accounting for the outstanding stability of the catalyst.