Preparation And Catalytic Performance Of Iron Oxide Nanodisk Supported Gold Catalysts For The Oxidation Of Toluene

Most of volatile organic compounds (VOC) are harmful to the atmosphere andhuman health. Many techniques have been utilized for VOC removal. Catalyticoxidation is believed to be one of the most effective pathways, in which the key issueis the availability of a high-efficiency and cheap catalyst. In this thesis, we preparedrod-, tube-, wire-, cube-, and disk-like Fe2O3nanoparticles using the hydrothermalmethod. A morphological effect on the catalytic performance for toluene oxidationunder the conditions of toluene concentration=1000ppm, toluene/oxygen molar ratio=1/400, and space velocity=20000mL/(g h) was observed. Among the differentlyshaped Fe2O3samples, the Fe2O3nanodisk exhibited the highest catalytic activity, andthe reaction temperatures (T10%, T50%, and T90%) required for10,50, and90%tolueneconversions were300,350, and410oC, respectively. The0.716.55wt%Au/Fe2O3nanodisk catalysts were prepared via a polyvinyl alcohol-protected reduction route.The Fe2O3nanodisk and Au NPs were rhombohedral and cubic in crystal structure,respectively. The surface areas and the Au NP diameters of0.716.55wt%Au/Fe2O3nanodisk were in the range of1319m2/g and2.23.4nm, respectively. There was astrong interaction between Au NPs and Fe2O3nanodisk in the0.716.55wt%Au/Fe2O3nanodisk samples. The surface adsorbed oxygen species and Au+speciesconcentrations increased with a rise in Au NPs loading, and the laoding of Au NPs ledto the enhancement in low-temperature reducibility of the sample. Compared to thebulk Fe2O3-supported counterpart under the same reaction conditions, thenanodisk-like Fe2O3-supported Au NPs showed better catalytic performance fortoluene oxidation, with the6.55wt%Au/Fe2O3nanodisk sample performing the best.The T10%, T50%, and T90%of toluene oxidation were135,200, and260oC over6.55wt%Au/Fe2O3nanodisk, whereas295,335, and400oC over6.82wt%Au/bulk Fe2O3,respectively. The apparent activation energies of toluene oxidation were in the rangeof45.765.1kJ/mol over0.716.55wt%Au/Fe2O3nanodisk. Therefore, it isconcluded that the good catalytic performance of6.55wt%Au/Fe2O3nanodisk wasassociated with its higher oxygen adspecies concentration, better low-temperaturereducibility, and strong interaction between Au NPs and the Fe2O3nanodisk.