PtSn/C catalysts for ethanol oxidation: The effect of stabilizers on the morphology and particle distribution

PtSn/C catalysts are synthesized by using four stabilizers, i.e., ethylene diamine tetra-acetic acid (EDTA), sodium citrate (NaCitrate), glycine and P-aminobenzoate (PABA) with the same reducing process and reaction parameters. XRD characterization shows all PtSn/C catalysts possess face-centered cubic structure with different alloying degree. TEM results show that stabilizers have a significant impact on the morphology and particle size distribution. PtSn/C EDTA and glycine have good particle dispersion with sphere and short nanowire morphology, while obvious particle agglomeration occurred on PtSn/C NaCitrate and PtSn/C PABA. Electrocatalytic activities of these PtSn/C catalysts for ethanol electrooxidation are also measured by cyclic voltammetry. Enhancement of electrocatalytic activity is ascribed to the high particle distribution of PtSn nanoparticles on the carbon supports, not the alloying degree of PtSn nanoparticles. The difference of glycine activities between PtSn/C EDTA and PtSn/C glycine could be ascribed to the variation in the amount of Sn oxides on the surface and density of inter-grain boundary regions in PtSn nanoparticles.