Influence of promoter on the catalytic activity of high performance Pd/PATP catalysts

A series of Pd-M/PATP (M = Fe, Cu, Ce) catalysts applied in low temperature CO oxidation were prepared by a deposition-precipitation (DP) method. The techniques of N-2 adsorption/desorption, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), temperature-programmed reduction by H-2 (H-2-TPR), BET and ICP were employed for catalyst characterization. It was found that the Pd-Fe/PATP catalyst had superior activity than Pd-Cu/PATP and Pd-Ce/PATP catalyst under similar condition. The characterization results showed Pd nanoparticles of Pd-Fe/PATP catalyst were dispersed highly and small size. The effects of Fe loading content, calcination temperature and H-2 reduction on low temperature CO catalytic oxidation were also investigated in detail. At 10 wt.% Fe loading, the catalyst which was calcined at 200 degrees C and no reduced with H-2 had the highest activity. An additional reduction peak which was indicated by H-2-TPR in the range of 200-250 degrees C (beside Pd oxide and Fe2O3) was detected in Pd-Fe-PATP catalyst when Fe content was 10 wt.%. It was ascribed to the reduction of weakly chemical-adsorbed oxygen and was very important to enhance the activity of Pd-Fe/PATP catalysts. From the analysis of research result, it could be seen that reaction pathway for low-temperature CO oxidation over Pd-Fe/ATP was due to the Langmuir-Hinshelwood reaction mechanism. (C) 2013 Elsevier B.V. All rights reserved.