Anti-Corrosive SnS_2/SnO_2 Heterostructured Support for Pt Nanoparticles Enables Remarkable Oxygen Reduction Catalysis via Interfacial Enhancement

摘要

The stability of Pt-based catalysts for oxygen reduction reaction (ORR) inhydrogen fuel cells is seriously handicapped by the corrosion of their carbonsupports at high potentials and acidic environments. Herein, a novel SnS_2/SnO_2 hetero-structured support is reported for Pt nanoparticles (NPs) as theORR catalyst, where Pt NPs are mainly deposited at the interfaces of SnS_2and SnO_2 moieties. The Pt-support interactions, which can be tuned by theconcentration of the heterointerfaces, can accelerate the electronic transferand enrich the electron density of Pt with a favorable shift of the d-bandcenter. In electrochemical measurements, the ORR mass activity (MA) of theoptimal Pt-SnS_2/SnO_2 catalyst at 0.9 V versus RHE (0.40 A mg_(Pt)~(?1)) is fourtimes higher than that of Pt/C. As for the stability, the electrochemical activesurface area and MA of Pt-SnS_2/SnO_2 are only decreased by 18.2 and 23.7after 50 000 potential cycles at a high potential region (1.0-1.6 V), representingthe best ORR stability among the reported Pt-based catalysts. Densityfunctional theory calculations indicate that the binding energy and migrationbarrier of Pt atom/cluster on the SnS_2/SnO_2 heterojunction are much higherrelative to other supports, accounting for the outstanding stability of thecatalyst.