| Summary: | 碩士 === 國立中央大學 === 環境工程研究所 === 100 === Perovskite-type oxides including La2NiO4, LaSrNiO4, and La0.7Ce0.3SrNiO4 were prepared by the citric acid complexation and used as catalysts for direct decomposition of NO. Moreover, non-thermal plasma technology was applied after calcinations of La0.7Ce0.3SrNiO4. In this study, i.e., citric acid complexation (without plasma treatment), N2-plasma-treated, and air-plasma-treated catalysts were tested for NO decomposition to understand the effect of plasma treatment on the catalytic performance. The catalysts before and after plasma treatment were characterized, respectively, to discern the effects. The activities of La2NiO4, LaSrNiO4, and La0.7Ce0.3SrNiO4 for NO decomposition were tested and the results indicate that in the same experimental parameters, La0.7Ce0.3SrNiO4 catalyst is of the highest NO decomposition with Ar, with the efficiency up to 49.89%. The inlet NO concentration was controlled at 1000 ppm, and the reaction temperature ranged from 600℃ to 900 ℃, while the space velocity was fixed at 8,000h-1. The influences of oxygen content and water vapor content on NO decomposition were also explored. In the absence of O2, NO decomposition achieved is much higher as N2 is used as carrier gas compared with Ar. With 1% oxygen content in the gas stream, NO decomposition decreased slightly to 99.12% and 44.97%, respectively, as N2 and Ar are used as the carrier gases. The results indicate that the activation of catalyst was slightly suppressed with 1% O2 content. On the other hand, NO decomposition decreases rapidly as the oxygen content is increased to 3% and 6%.
Non-thermal plasma is applied to modify the performance of perovskite-type oxides catalyst. The operating parameters are as following：gas flow rate is 1000 sccm, space velocity is 1241 h-1, the applied voltage is 16.5kV, and the discharge frequency is 100 Hz with either nitrogen or air as carieer gas. At 900℃, NO decomposition achieved with La0.7Ce0.3SrNiO4 catalyst before plasma treatment as N2 is used as carrier gas is much higher than that the catalyst after plasma treatment in the presence of 0% or 1% O2, however, as the oxygen content is increased to 3% and 6%, the La0.7Ce0.3SrNiO4 catalyst before plasma treatment activity is significantly decreased to 24.66% and 6.54%, respectively, as N2 is used as the carrier gas. The results lower than the La0.7Ce0.3SrNiO4 catalyst after plasma treatment with N2 as the carrier gas. As the oxygen content is increased to 3% and 6%, the N2-plasma-treatment catalyst activity is 36.45% and 17.81%, respectively, and air-plasma-treatment catalyst activity is 28.55% and 12.27%, respectively. The results indicate that the the catalysts after plasma treatment possess strong tolerance in the presence of 3% and 6% oxygen content.
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