Ethanol oxidation activity and structure of carbon-supported Pt-modified PdSn-SnO2 influenced by different stabilizers

PdSn-SnO2 nanoparticles supported on Vulcan XC-72 carbon were synthesized by chemical reduction in the presence of three different stabilizing agents: ethylene diamine tetra-acetic acid (EDTA), sodium citrate (Nacitrate) and hexamethylenetetramine (HMTA). TEM analysis showed that PdSn-SnO2/C catalyst made using the HMTA stabilizer produced the smallest particle size. XRD analysis detected the presence of PdSn alloy and the SnO2 phase in all three PdSn-SnO2/C samples, and showed that PdSn-SnO2 (HMTA) had the smallest lattice parameter. After PdSn-SnO2 samples were modified by Pt, the particle size distribution and average size of nanoparticles of Pt-PdSn-SnO2 did not obviously change, and the fcc structure of PdSn in all three samples was retained. XPS measurement showed a higher upshift of Pt 4f binding energy occurred for Pt/PdSn-SnO2/C (HMTA) compared to those of Pt/PdSn-SnO2/C (EDTA) and Pt/PdSn-SnO2/C (Nacitrate). Pt/PdSn-SnO2/C (HMTA) was also found to have the highest CO and ethanol oxidation activity among the three catalysts. (C) 2013 Elsevier Ltd. All rights reserved.