The oxidation of carbon monoxide and methane by nano and regular Fe2O3

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Kwon, Soon-Chul
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Civil, Construction, and Environmental Engineering

The catalytic performances of nano and regular Fe2O3 in the oxidation of methane (CH4) and carbon monoxide (CO) singly and in combination were compared in a laboratory study. The major oxidation product is carbon dioxide (CO2). The performance of the nanocatalyst for oxidation of CH4 and CO was studied under variable conditions of temperature, concentration and space-time. It was demonstrated that 40 mg of Fe2O3 nanoparticles (NANOCAT superfine iron oxide) was much more effective than 400mg of non-nano Fe2O3-PVS (Bailey-PVS Oxides) in calatalyzing the oxidation. Furthermore, in the oxidative coupling of CH4 and CO, the efficiency of mixed gas conversion was also higher when NANOCAT was used as the catalyst than when Fe2O3-PVS was used, and almost complete oxidation of the mixed gas phases was observed. These results support the hypothesis that the small particle size (3nm), high surface area (245 m2/g), and denser surface coordination of the nanocatalyst can contribute to its better performance as a catalyst. Generally, the oxidation of CO and CH4 increased significantly with increase in temperature. In the presence of oxygen, the reaction is zero-order on CO. The oxidation efficiency was not affected by the CO concentrations at any temperature (more than 2000C). However, lower concentrations in the gas phase contributed to higher oxidation efficiency over the entire range of temperatures. The oxidation of CH4 is quite complicated, and has not been clearly delineated. An increase in the inlet gas flow rate caused a lower conversion rate. An examination of space time effect of CO oxidation reveals that the higher space time between carbon monoxide and NANOCAT has little or no effect on oxidation efficiency. In contrary to CO oxidation, the CH4 and mixed gas (CO and CH4) oxidations were accelerated by increased space time with NANOCAT.

Sat Jan 01 00:00:00 UTC 2005