Gold catalysts on ceria doped with MeOx (Me = Fe, Mn, Co and Sn) for complete benzene oxidation: effect of composition and structure of the mixed supports

Abstract

Gold catalysts supported on ceria doped with different metal oxides (Fe, Mn, Co and Sn) were synthesized using two techniques: CP and mechanochemical activation. The catalytic activity in complete benzene oxidation (CBO) was studied. The samples were characterized by means of XRD and high resolution transmission electron microscopy, and non-significant differences in the average size and the distribution of gold particles were observed. This means that the main reason for the different catalytic behavior in CBO has to be searched in the composition and structure of the supports. In spite of the higher hydrogen consumption (e.g., higher oxygen mobility) estimated by means of TPR, the gold catalysts on ceria doped with transition metal oxides generally are less active than gold/ceria catalyst. This observation could be explained taking into consideration that the key factor for the high oxidation activity is not the oxygen supplying but the activation of the very stable benzene molecule. The higher catalytic activity in comparison with that of the gold/ceria catalyst was observed only using a mixed ceria-CoO x support mechanochemically prepared. Very high and stable catalytic activity in CBO was obtained over this sample.

Gold Catalysts on Y-Doped Ceria Supports for Complete Benzene Oxidation

“…It is in agreement with the previously discussed suggestion [14] that depending on the catalytic system, the key factor for the high oxidation activity could not be the oxygen supply but the activation of the very stable benzene molecule.…”

“…It is known that CeO2 modification with proper metal dopants leads to a defective structure (in particular the formation of oxygen vacancies), increasing the oxygen mobility in the ceria-based catalysts. Studying complete benzene oxidation (CBO) over gold catalysts on ceria doped with MeOx (Me = Fe, Mn, Co and Sn), Ilieva et al [14] came to the conclusion that in some cases, independent of the easy oxygen provision enhanced by gold and ceria modification, the most essential factor responsible for the high oxidation activity could be related to the activation of the very stable benzene molecule.…”

Development of a Biphasic Electroreactor with a Wet Scrubbing System for the Removal of Gaseous Benzene

“…First, solid sate individual process like solid catalysts in quartz tubular fixed bed flow reactor at atmospheric pressure was used in catalytic oxidation of volatile organic compounds (VOCs) including benzene for partial oxidation of petrochemical materials to minimizing formation of undesirable byproduct . For the total oxidation of benzene, MnO, Cu-MnO, ZnO, FeO, and CoO high temperature catalysts (400 °C) have been devised in a fixed bed reactor. − However, the reactivation procedures required for catalysts are problematic for bulk processing.…”

Electric Field Promoted Complete Oxidation of Benzene over PdCexCoy Catalysts at Low Temperature

“…Exposure to VOCs can induce mutagenic and teratogenic effects on human body and cause cancer, cardiovascular, and other insusceptible diseases. Among various VOC removal methods, catalytic oxidation has been suggested as the most effective technique and has been extensively investigated for many decades [2][3][4][5][6][7][8][9][10][11]. Precious metal based catalysts such as Pd and Pt have be proved to be highly active for benzene oxidation.…”