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 SnO2 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 O2 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 SnO2 in PtSn/C.

► PtSn/C electrocatalysts are prepared by alcohol-reduction process.
► The pH value of the refluxing solution is controlled at 9 or 12.
► Physical properties of the catalysts are characterized.
► The PtSn12 sample shows higher ORR activity than Pt/C even with lower Pt loading.
► PtSn12 is also found to be more stable than Pt/C.