VOLUME 62 : 2014

The study aimed to prepare and characterize carbon black- and graphene-supported PtSn catalysts as possible electrocatalysts alternative for glucose oxidation. Carbon-based PtSn catalysts were successfully synthesized by the borohydride-facilitated reduction method as confirmed by energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD) analyses. The XRD pattern also revealed the formation of PtSn nanoparticles of less than 5 nm size. The electro-oxidation of glucose on PtSn/C was studied by cyclic voltammetry at a potential range from –1.0 V to 0.6 V (vs. Ag/AgCl). Three oxidation peaks at –0.8 V, –0.3 V, and 0.05 V, which correspond to the oxidation processes of glucose, were observed. The addition of a secondary metal, Sn, showed an enhanced catalytic activity of Pt towards glucose electro-oxidation. The optimization of metal loading and metal ratio using carbon black (XC-72) as support was studied and the results revealed that the optimum metal loading is 40% while the optimum PtSn ratio is 1:0.01 using the 40% metal loading. The lower amount of Sn added can lower the poisoning effect of Pt and thus only act as a promoter. The optimized parameters for carbon black were used for graphene as support. The data revealed that graphene as a support has an enhanced electrocatalytic activity compared to carbon black with a peak current of 12.82 mA/cm² and 6.97 mA/cm² , respectively. The XRD data indicates that graphene is a promising support material that could modify the catalytic properties of PtSn bimetallic electrocatalyst for fuel cell catalysis.

Keywords: Pt/Sn nanoparticles, PtSn/C, PtSn/graphene, glucose electro-oxidation