Electrocatalytic properties of carbon nanotubes supported ternary PtSnIn catalysts for ethanol electro-oxidation

The carbon nanotubes (CNTs) supported ternary PtSnIn (PtSnIn/CNTs) catalysts with different molar compositions were prepared using one-step chemical reduction process. X-ray diffraction (XRD) data exhibited the typical characteristic of a crystalline Pt face-centered cubic (fcc) structure, compared with that of Pt/CNTs, the lattice parameter of PtSnIn/CNTs catalyst increases, its diffraction peaks are shifted slightly to a lower 2θ values. It indicates that Sn and In are well incorporated into Pt alloy lattice. Transmission electron microscopy (TEM) shows that the PtSnIn nanoparticles with a crystallite size of 3nm are highly dispersed on the surface of CNTs. The electrocatalytic activity of the composite catalysts for electro-oxidation of ethanol was investigated by cyclic voltammogram (CV), linear sweep voltammetry (LSV) and chronoamperometry (CA). The results indicate that the change of In and support using CNTs could promote significantly the catalytic activity for ethanol electro-oxidation. The PtSnIn/CNTs catalysts exhibit a higher intrinsic activity for ethanol electro-oxidation than Pt3Sn/CNTs and PtSnIn/C. The Pt3SnIn/CNTs catalyst with an atomic ratio of 3:1:1 is the best among all different compositions for electro-oxidation of ethanol.