Preparation of PtSn/C electrocatalysts with improved activity and durability toward oxygen reduction reaction by alcohol-reduction process

PtSn/C electrocatalysts were prepared by alcohol-reduction process for the oxygen reduction reaction. The physical and morphological properties of the synthesized catalysts were characterized by energy dispersive spectrometer, X-ray diffraction, and high resolution transmission electron microscope. The electrochemical performances were analyzed by cyclic voltammetry, linear scan voltammetry and long-term durability. Results show that samples prepared at pH 12 have smaller particle size than those prepared at pH 9 due to the formation of SnO ₂ phases in PtSn/C catalysts. When the carbon support was added before the reflux process, the alloy nanoparticles having a size of 4.8 nm are uniformly dispersed on the C support. Although the Pt loading of PtSn12 is only about 75% of the commercial Pt/C, its ORR activity is promoted to 131% due to enhanced catalyst activity and O ₂ adsorption and dissociation on the catalyst surface. Furthermore, based on the accelerated durability test, the ORR activity after 500 cycles of PtSn12 is 1.34 times higher than that of Pt/C, suggesting that PtSn12 is more chemically stable in the acid environment due to the coexistence of SnO ₂ in PtSn/C.