| Currently, it is a major problem to control the environment pollution, and the abatement of NOx has been a hotpot of study from home and abroad. The noble metals catalysts are now facing the crisis of resource scarcity, and then many studies have attracted much attention with transition metals. TiO2 has outstanding resistant to sulfur poisoning and higher catalytic activity and selectivity for nitrogen oxides abatement. But it exhibits not only a low specific surface area but also poor thermal stability.γ-Al2O3 can be usually obtained with surface areas larger than 200m2/g, also it has excellent texture, mechanic and thermal properties. TiO2/γ-Al2O3 binary system is regarded as very promising supports for DeNOx catalysts and in many other potential applications, and it attaches more and more studies about this subject. CuO based catalysts are always used in NO removal reactions and obtain good NO catalytic activities. Diesel and lean-burn gasoline engines have been the alternatives to conventional gasoline engine, the selective catalytic reduction of nitric oxide with hydrocarbons (HC-SCR) recently receives increasing attention due to the need for replacing NH3-SCR process. Among hydrocarbons, methane offers the benefits of low cost and wide availability compared to other hydrocarbons. Using Non-thermal-plasma technique (NTP) as an aid to CH4-SCR has shown its value to be effective for extending the low temperature window of metal oxide catalysts and many studies have been carried on NO abatement with plasma-catalyst system. In non-thermal discharge, the majority of electrical energy goes into the production of high-energy electrons rather than into gas heating, it can activate NO and CH4 molecules at low temperature and improve the NO+CH4 reaction.In this work, it consists two parts. At first, we prepared a series of TiO2/γ-Al2O3 support with precipition and co-precipition, and loaded CuO to synthesize the catalysts. We studied the NO+CO reaction over these catalysts and used BET, TG-DTA, H2-TPR, XRD, Raman and FT-IR techniques to characterize our catalysts. For the second, we investigated the plasma-assisted catalysts for NO+CH4 reduction. And studied various catalysts over four NO+CH4 reactions (NO+CH4, NO+CH4+O2, NO+CH4+NTP, NO+CH4+O2+NTP) to find out the effects on NO and CH4 conversions. And other methods such as XPS and NO-TPD are employed to characterize the catalysts. Some specific conclusions are drown from this work as follows:1. TiO2/γ-Al2O3 (P) was prepared with TiCl4 material, and the catalytic activities of CuO/TiO2/γ-Al2O3 (P) were examined using a GC micro-reactor NO+CO reaction system. The catalysts showed high activities in NO+CO reaction, especially for the catalyst of 12%CuO/15%TiO2/γ-Al2O3. The NO conversion temperature(T100%) was 300℃by air pretreatment, higher than NO conversion for 12%CuO/TiO2 and 12%CuO/γ-Al2O3 at the same temperature, which has only 18.1% and 80.1%, respectively. It showed a big success for TiO2 modifiedγ-Al2O3 over NO+CO reaction. The structural and reduction properties of CuO/TiO2/γ-Al2O3 (P) catalysts were analyzed using the H2-TPR, XRD and FT-IR methods. It was found that proper amount of TiO2 increased the CuO dispersion on TiO2/γ-Al2O3. When NO and CO were adsorbed on 12%CuO/15%TiO2/γ-Al2O3, in FT-IR experiment, H2-pretreated 12%CuO/15%TiO2/γ-Al2O3 (P) could weaken the adsorption of NO2 and other NOx on the catalysts, and the peak temperatures of N2O absorption were 200℃by air and 150℃by H2 pretreatment, Which gave us a good message to study the better catalytic reactivity for catalyst after H2 pretreatment in NO+CO reaction.2. A serious of TiO2 modified alumina mixed-oxides with high specific surface area and better thermal stability are prepared from Al(NO3)3·9H2O, NH3·H2O and TiCl4. The BET surface area of 15%TiO2/γ-Al2O3 calcined at 500℃and 900℃for two hours has 267m2/g and 100m2/g, respectively. And at the same time, we studied the NO+CO reaction over CuO/15%TiO2/γ-Al2O3(C-P) catalysts, and found it had the same catalytic activity as CuO/15%TiO2/γ-Al2O3 (P), only decreased a little. XRD, FT-IR and Raman suggested that the w%CuO/15%TiO2/γ-Al2O3 (C-P) catalyst had well-distributed structure, stronger effect with support, which enhanced CuO spread on the 15%TiO2/γ-Al2O3 (C-P) carriers that could prevent micro-crystalline CuO, and restrain the reaction activity in NO+CO reaction. 3. By using a hybrid system integrating plasma activation and a 12%CuO/ TiO2/γ-Al2O3 catalyst reaction equipment, the reactions of NO+CH4+O2 were studied under different conditions including plasma only, catalyst only and plasma with catalyst. When only existing plasma, the NO and CH4 conversion increased with higher plasma power supply, and addition of 2.5%O2 increased NO and CH4 conversion. Only catalysts, the NO and CH4 conversion both increased with temperature and reached 30% and 20%, respectively. And at the same time, the NO conversion firstly increased with O2 content and then decreased, and CH4 conversion increased with O2 content. When plasma and catalyst coexisted, the conversion trend of the NO and CH4 with O2 content was consistent with only catalyst. Besides, the NO conversion was at the range of 15% to 35% and obviously increased the low temperature NO conversion. For the CH4 conversion, it was promoted greatly to 90%.4. Removal of NO and CH4 gases was examined using non-thermal-plasma (NTP) assisted 12%CuO/15%TiO2/γ-Al2O3 under four reaction conditions (NO+CH4, NO+CH4+O2, NO+CH4+NTP, NO+CH4+O2+NTP). Methods of BET, XRD, H2-TPR and XPS were used to investigate the catalyst characters before and after the reactions. The results showed that plasma discharge improved low-temperature reaction activity, and addition of O2 increased NO and CH4 conversion. Pore size distribution of 15%TiO2/γ-Al2O3 was mainly as micro-pores and meso-pores. Specific surface area of 12%CuO/15%TiO2/γ-Al2O3 changed little before and after NO+CH4 reaction, but its surface crystalline CuO reduced to Cu2O and Cu after the reaction. Highly dispersed CuO and bulk CuO reduction peak of the catalyst vanished after NO+CH4 reaction. Cu2+ still existed to some extent on the surface of the catalyst after reaction, compared with significant increase in Cu+ and Cu0 species.5. The effect of CeO2 modified CuO-15%TiO2/γ-Al2O3 catalysts on NO+CH4 reaction. The loading amount of CeO2 and CuO, calcined temperature and the pretreatment by CH4, H2 and NO+CH4 are studied. We found that 6%CuO/5%CeO2/15%TiO2/γ-Al2O3 catalysts has better catalytic activity than others for NO+CH4 reaction. And when the Plasma assisted-6%CuO/5%CeO2/ 15%TiO2/γ-Al2O3 catalyst for NO+CH4+NTP (P=30W), for NO+CH4, it had NO total conversion and 80% CH4 conversion at 300℃, and at the same temperature the NO and CH4 conversion had 28.1 and 14.7%, respectively. XPS detected the 6%CuO/5%CeO2/15%TiO2/γ-Al2O3 pretreated by the CH4, H2 and NO+CH4 has Cu0, Cu+ and Cu-O-Ti-O respectively, probably these species can favor the NO+CH4 reaction.
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