Effect of platinum dispersion on the catalytic activity of Pt/Al2O3 for the oxidation of carbon monoxide and propene

Effect of Pd dispersion on the catalytic activity of Pd/Al2O3 for C3H6 and CO oxidation

“…These bands increased with reaction time up to 1 min, and then decreased after that with an appearance of new bands at 1693, 1575, 1455 and 1375 cm −1 assignable to (C O) of adsorbed C 3 H 6 species [40], carbonate/carboxylate species [40] and formate species [41], respectively. The formation and reaction behavior of adsorbed species on Pd/Al 2 O 3 are in good agreement with those on Pt/Al 2 O 3 [39], suggesting that the catalysis of Pt and Pd for C 3 H 6 oxidation is very similar and these species observed here are mainly adsorbed on the surface of Al 2 O 3 . It should be noted that no significant difference in the feature of IR spectra was observed for D Pd = 0.11.…”

“…Nevertheless, the fact that the TOF of CO oxidation does not depend on the Pd dispersion suggests that CO oxidation proceeds predominantly on metallic Pd 0 sites. According to the CO-TPR profiles for Pd/Al 2 O 3 reported elsewhere [39], the reduction of PdO by CO takes place from the temperature around 100 • C and then reaches the maximum at 175 • C. This suggests that the surface of PdO x sites can be reduced to metallic Pd 0 by CO even under the reaction condition.…”

“…On the basis of in situ FT-IR spectroscopy, we have recently proposed the participation of the Pt − Al 2 O 3 interface as catalytically active sites in the total oxidation of hydrocarbons [37][38][39]. We found that acrylate species participates as a reaction intermediate in C 3 H 6 oxidation on Pt/Al 2 O 3 and the formation and reaction behavior of the acrylate species is different depending on the Pt dispersion.…”

Hydrogenation of Phenol over Pt/CNTs: The Effects of Pt Loading and Reaction Solvents

“…Pore size distributions were obtained from the isotherm adsorption branch, using the Barrett-Joyner-Halenda model. The Pt dispersion, expressed in terms of CO chemisorbed/Pttotal, was calculated by assuming a CO-to-surface Pt atom ratio of 1:1 [26]. XRD was performed on a Rigaku D/max-2200PC diffractometer (Rigaku, Tokyo, Japan) using CuKα radiation.…”

Development of Diesel Hydrocarbon Oxidation Catalysts Aimed at Reducing Platinum Group Metals Usage

“…37), 38) The catalytic reaction predominantly occurs on the catalyst surface, so the particle size of the platinum group metal (PGM) is one of the important factors to determine the catalytic activity. For example, Gandhi and Shelef 39) reported that alkane oxidation on automotive catalysts with highly dispersed PGMs is relatively slow and the catalyst including too large particles also becomes less efficient due to a lower fraction of surface atoms.…”