Tin dioxide facilitated truncated octahedral Pt3Ni alloy catalyst: synthesis and ultra highly active and durable electrocatalysts for oxygen reduction reaction
Abstract
This paper describes a facile and surfactant-free synthesis of a SnO2 modified truncated octahedral Pt3Ni alloy nanoparticle electrocatalyst by using neat N-formylpiperidine as the solvent, which is capable of controlling the formation of the Pt3Ni–SnO2–C triple junction nanostructure, and the shape/surface composition of Pt3Ni nanoparticles. The area-specific oxygen reduction reaction (ORR) activity for the Pt3Ni/SnO2–C catalyst reaches up to 2.67 mA cm−2, which is 2.4 times that of the Pt3Ni/C catalyst. The electrochemical stability of the Pt3Ni/SnO2–C catalyst is 2.5 times as high as that of Pt3Ni/C catalysts. The significant improvement in ORR activity and durability can be mainly ascribed to the strong interaction of the Pt3Ni alloy and SnO2 and the anchoring effect of Pt3Ni nanoparticles by both SnO2 and C at the Pt3Ni–SnO2–C triple junction nanostructure as well as the Pt-rich surface composition, which could hinder the dissolution of cheap Ni metal. The improved catalytic behavior in the ORR highlights the importance of surfactant-free synthesis and the unique shaped metal alloy–metal oxide–carbon triple junction nanostructure.