Size and support effects for CO oxidation on supported Pd catalysts

Abstract

Supporting Pd catalysts characterized significant different size distribution were obtained using PdCl2, [Pd(NH3)(4)](NO3)(2) and Pd(acac)(2) as precursors. High-resolution transmission electron microscopy (TEM), X-ray diffraction (XRD), in-situ Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy were used to examine the dispersion of Pd. Catalytic performance measurements show that the activities for CO oxidation increase as the Pd particle size decreases and the O-2/CO ratio increases. The activities under oxygen rich conditions are significantly higher than those at near the stoichiometric conditions. Pd on TiO2 prepared by the Pd(acac)(2) precursor is highly dispersed, leading to a considerable activity for CO oxidation at near room temperature. CO oxidation on the 1 wt% Pd/TiO2 and under an O-2/CO ratio of 1 characterized an apparent activation energy of 36.7 kJ/mol, which is closed to those reported for CO oxidation on the supported Au catalysts. The present work demonstrates a high catalytic activity of highly dispersed noble metals, and suggests a promising approach of using noble metals as catalysts with exceeding high efficiency.National Natural Science Foundation of China [20873109]; National Basic Research Program of China (973 program) [2005CB221401, 2010CB732303]; Chinese Ministry of Education [309019]; Ph.D. Programs Foundation of Chinese Ministry of Education [200803841011]; Natural Science Foundation of Fujian Province, China [2008J0168

Ageing induced improvement of methane oxidation activity of Pd/YFeO3

“…Contrary to CH 4 , CO oxidation activity of 2Pd/YFO, 0.5Pd/YFO and Pd/ACZ decreases upon ageing (Table 2) and the structural changes produced by thermal ageing appear more severe likely as a result of Pd particle growth. 82,83 This is in agreement with observations on Pd-based catalysts aged on a dynamometer. 84 Besides, the YFeO 3 support alone exhibited deactivation upon consecutive reaction runs.…”

Swallowtail model for predicting the global bifurcation behavior of CO oxidation reactions

“…Catalytic CO oxidation on platinum group metals is of great interest for fundamental research [1][2][3][4], and has been known to exhibit nonlinear phenomena such as hysteresis and bifurcation. Elucidation of the nonlinear mechanisms is important for catalyst design and control of reaction routes.…”

High‐Performance Ru1/CeO2 Single‐Atom Catalyst for CO Oxidation: A Computational Exploration

“…Thus, the high activity of Ru might contribute to its interaction with the FeO x support. Actually, the support effects for CO oxidation have been examined experimentally . For example, Ito et al .…”

“…Actually,t he support effects for CO oxidation have been examined experimentally. [32][33][34][35][36][37][38][39][40] For example, Ito et al [34] revealed that the activity of Rh-based catalysts for the CO preferentialo xidation reactionf ollows the order: Rh/Nb 2 O 5 > Nb 2 O 5 -Rh/SiO 2 > Rh/SiO 2 > RhNbO 4 /SiO 2 .L ie tal. [35] prepared various supported platinum catalysts (Pt/MeO x ,M e= Fe, Zn, Al, Ni)b yc olloid depositioning, and found that Pt/Fe 2 O 3 shows unusual low-temperaturea ctivity and long-term stability.M oreover,o xide-supported Ru catalysts with different substrates have been synthesized, such as g-Al 2 O 3 [41][42][43] and TiO 2 , [44] and are well known for their high activity for CO oxidation at high temperature (100-400 8C), [45][46][47][48] but have al ow activity at 80 8C.…”