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 N2 adsorption/desorption, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), temperature-programmed reduction by H2 (H2-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 H2 reduction on low temperature CO catalytic oxidation were also investigated in detail. At 10 wt.% Fe loading, the catalyst which was calcined at 200 °C and no reduced with H2 had the highest activity. An additional reduction peak which was indicated by H2-TPR in the range of 200-250 °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.