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含氯挥发性有机化合物(CVOCs)对环境安全和人类健康存在持久性污染和危害。催化氧化法具有操作温度低和CO_2选择性高等优点,被广泛应用于CVOCs催化降解。催化剂作为CVOCs催化降解过程的核心部分,受到很多学者的关注。分析酸性分子筛、金属改性分子筛和复合氧化物酸性材料对各种CVOCs催化氧化活性、副产物控制性能、CO_2和HCl选择性的影响。结果表明,催化剂表面酸中心、氧化中心和催化剂表面结构性质在CVOCs催化氧化过程中起重要作用。较多酸中心和较大比表面积有利于CVOCs分子的吸附和活化,提高HCl选择性。而较多氧化中心则有利于CVOCs深度氧化,减少副产物产生,提高CO_2选择性。 相似文献
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ZrO2负载过渡金属催化剂的结构和催化性能 总被引:7,自引:0,他引:7
运用 X R D 、 T P R 及 T P O 技术研究了 Zr O2 负载过渡金属氧化物 Cu Ox 、 Fe Ox 、 Co O x 、 Ni Ox 、 Mn O x 和 Cr Ox 的物相结构、还原和氧化性能,并以 C O 氧化反应为探针考察了催化剂的氧化活性。结果表明, 过渡金属- Zr O2 之间的相互作用,阻止了载体 Zr O2 从无定形 Zr O2 →四方 Zr O2 →混合相→稳定的单斜 Zr O2 的转变和 Zr O2 颗粒的增长,并导致过渡金属氧化物在 Zr O2 表面的高度分散。催化剂的氧化- 还原性能随载体上负载的过渡金属氧化物的不同而不同, C O 氧化活性顺序为: Cu O x > Co O x > Mn Ox > Fe O x > Ni O x > Cr O x 。 相似文献
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Volatile organic compounds (VOCs) are considered as a major pollutant in indoor and outdoor air.More stringent environmental regulations have been implemented in order to reduce the VOC emissions.One of the techniques available for destructive removal of VOCs is catalytic oxidation.In the present work,Al/Rare Earths (REE: Y,Ce,La,Pr and Nd) pillared clays (PILCs) were used to support 0.2 wt.% of palladium for the complete oxidation of low concentration of benzene.The supports and catalysts were characterized by XRD,N2 adsorp-tion/desorption,FTIR spectroscopy,HRTEM and H2-TPR techniques.The results indicated that after Al and Al/REE pillaring,the basal spac-ing,SBET,Amic and Vmic of Al and AlREE-PILC had a considerable increase compared with those of Na-mmt.Activity tests of deep oxidation of benzene showed that the catalytic activity of Pd catalysts supported on Al and AlREE-PILC were much higher than that on initial clays,which was due to the fact that optimized structure of PILCs,such as large basal spacing,high SBET and porosity,improved Pd dispersion and increased the active sites of Pd.Especially for Pd/AlCe-PILC,the temperature of complete oxidation was about 280 oC,exhibiting the highest catalytic activity. 相似文献
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Volatile organic compounds (VOCs) are considered as a major pollutant in indoor and outdoor air.More stringent environmental regulations have been implemented in order to reduce the VOC emissions.One of the techniques available for destructive removal of VOCs is catalytic oxidation.In the present work,Al/Rare Earths (REE: Y,Ce,La,Pr and Nd) pillared clays (PILCs) were used to support 0.2 wt.% of palladium for the complete oxidation of low concentration of benzene.The supports and catalysts were characterize... 相似文献
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Pt、Pd及其双金属催化剂表面氧性能与催化活性的研究 总被引:1,自引:0,他引:1
用TPD-MS及CO氧化活性测定等方法研究了Pt/Al_2O_3、pd/Al_2O_3及Pt-Pd/Al_2O_3催化剂上表面氧的脱出-恢复性能及催化活性。结果表明,Pt、Pd单金属催化剂上的表面氧随金属负载量增加,氧脱附峰面积增大,起脱温度降低,催化氧化活性提高。双金属催化剂上的表面氧性质与单金属催化剂的不同,两种金属间可能发生相互作用,促进各自的氧化还原性能:随Pd/Pt比增加,脱附峰面积明显增大,催化活性也提高,催化活性与催化剂表面氧吸脱附性能有密切的联系。 相似文献
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MCM-41分子筛固载羧基钯(Ⅱ)配合物催化剂的制备、表征和催化性能(Ⅱ)催化Heck偶联反应性能 总被引:1,自引:0,他引:1
合成了一系列新的MCM-41分子筛固载羧基钯(Ⅱ)配合物, 并研究了其催化碘代芳烃与共轭烯烃的Heck偶联反应的性能以及反应温度、溶剂和碱试剂对催化性能的影响。结果表明,MCM-41分子筛固载双羧基钯(Ⅱ)配合物对催化Heck偶联反应具有高的活性、立体选择性和稳定性,在Et3N-DMF或Bu3N-DMF溶剂体系中,在70℃下7 h内可高产率地合成一系列取代的反式偶联产物,其催化性能明显优于无定形SiO2固载的羧基钯(Ⅱ)配合物,而且表面双羧基改性的催化性能也优于单羧基改性的催化剂。 相似文献
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