Pt/Tin Oxide/Carbon Nanocomposites as Promising Oxygen Reduction Electrocatalyst with Improved Stability and Activity

Abstract In this report, a novel nanostructural Pt/SnO 2 /C catalyst was synthesized by depositing Pt nanoparticles on the SnO 2 /C surface. X-Ray Diffraction and Transmission Electron Microscopy characterizations showed that Pt nanoparticles with an average size of ∼2.7 nm were uniformly dispersed on the Pt/SnO 2 /C catalysts. High Resolution Transmission Electron Microscopy images revealed that Pt nanoparticles were bonded with both SnO 2 and C at the SnO 2 /C junctions, forming Pt/SnO 2 /C triple junction nanostructures in Pt/SnO 2 /C catalysts. Electrochemical measurements showed that specific activity towards oxygen reduction reaction (ORR) of Pt/SnO 2 /C catalysts was 2.3 times as high as that of conventional Pt/C catalysts. Accelerated degradation test (ADT) indicated that electrochemical stability of Pt/SnO 2 /C was twice as high as that of conventional Pt/C catalysts. The improved performance can be attributed to the presence of Pt/SnO 2 /C triple junction nanostructures, in which Pt nanoparticles were thermodynamically favored to deposit at the SnO 2 /C junctions, and then be anchored simultaneously by both SnO 2 and C.