CO oxidation has been investigated on three CuO/Ce02 catalysts prepared by impregnation, co-pre- cipitation and mechanical mixing. The origin of active sites was explored by the multiple techniques. The catalyst prepa...CO oxidation has been investigated on three CuO/Ce02 catalysts prepared by impregnation, co-pre- cipitation and mechanical mixing. The origin of active sites was explored by the multiple techniques. The catalyst prepared by impregnation has more highly dispersed CuO and stronger interactions between CuO and CeO2 to promote the reduction of CuO to Cu＋ species at the Cu-Ce interface, leading to its highest catalytic activity. For the catalyst prepared by co-precipitation, solid solution structures observed in Raman spectra suppress the formation of the Cu-Ce interface, where the adsorbed CO will react with active lattice oxygen to form CO2, and thus it displays a lower catalytic performance. No Cu-Ce interface exists in the catalyst prepared by the mechanical mixing method due to the separate phases of CuO and CeO2, resulting in its lowest activity among the three catalysts.展开更多
In this work, xylene removal from waste gas streams was investigated via catalytic oxidation over Pd/ carbon-zeolite and Pd/carbon-CeO2 nanocatalysts. Acti- vated carbon was obtained from pine cone chemically activate...In this work, xylene removal from waste gas streams was investigated via catalytic oxidation over Pd/ carbon-zeolite and Pd/carbon-CeO2 nanocatalysts. Acti- vated carbon was obtained from pine cone chemically activated using ZnC12 and modified by HaPO4. Natural zeolite of clinoptilolite was with HC1, while nano-ceria modified by acid treatment was synthesized via redox method. Mixed supports of carbon-zeolite and carbon- ceria were prepared and palladium was dispersed over them via impregnation method. The prepared samples were characterized by X-ray emission scanning electron diffraction （XRD）, field microscopy （FESEM）, Brunauer-Emmett-Teller surface area （BET）, Fourier transform infrared spectroscopy （FTIR） and thermogravi- metric （TG） techniques. Characterization of nanocatalysts revealed a good morphology with an average particle size in a nano range, and confirmed the formation ofnano-ceria with an average crystallite size below 60 nm. BET analysis indicated a considerable surface area for catalysts （-1000 m^2·g^-1）. FTIR patterns demonstrated that the surface groups of synthesized catalysts are in good agreement with the patterns of materials applied in catalyst synthesis. The performance of catalysts was assessed in a low-pressure catalytic oxidation pilot in the temperature range of 100℃-250℃. According to the reaction data, the synthesized catalysts have been shown to be so advantageous in the removal of volatile organic compounds （VOCs）, represent- ing high catalytic performance of 98% for the abatement of xylene at 250℃. Furthermore, a reaction network is proposed for catalytic oxidation of xylene over nanocata- lysts.展开更多
将微波与湿式催化氧化技术相结合,以硫酸改性纳米氧化铈为催化剂,H2O2为氧化剂,降解腈纶废水。研究了催化剂和氧化剂的用量、反应时间、反应温度等因素对有机物去除率的影响,确定了最佳反应条件为50 m L腈纶废水(COD 635 mg/L)投加0.25 ...将微波与湿式催化氧化技术相结合,以硫酸改性纳米氧化铈为催化剂,H2O2为氧化剂,降解腈纶废水。研究了催化剂和氧化剂的用量、反应时间、反应温度等因素对有机物去除率的影响,确定了最佳反应条件为50 m L腈纶废水(COD 635 mg/L)投加0.25 g酸化纳米Ce O2催化剂和0.3 m L 6%的H2O2,室温下搅拌3 h,微波辐射140℃下反应60 min,COD平均去除率达到89.7%。展开更多
文摘CO oxidation has been investigated on three CuO/Ce02 catalysts prepared by impregnation, co-pre- cipitation and mechanical mixing. The origin of active sites was explored by the multiple techniques. The catalyst prepared by impregnation has more highly dispersed CuO and stronger interactions between CuO and CeO2 to promote the reduction of CuO to Cu＋ species at the Cu-Ce interface, leading to its highest catalytic activity. For the catalyst prepared by co-precipitation, solid solution structures observed in Raman spectra suppress the formation of the Cu-Ce interface, where the adsorbed CO will react with active lattice oxygen to form CO2, and thus it displays a lower catalytic performance. No Cu-Ce interface exists in the catalyst prepared by the mechanical mixing method due to the separate phases of CuO and CeO2, resulting in its lowest activity among the three catalysts.
文摘In this work, xylene removal from waste gas streams was investigated via catalytic oxidation over Pd/ carbon-zeolite and Pd/carbon-CeO2 nanocatalysts. Acti- vated carbon was obtained from pine cone chemically activated using ZnC12 and modified by HaPO4. Natural zeolite of clinoptilolite was with HC1, while nano-ceria modified by acid treatment was synthesized via redox method. Mixed supports of carbon-zeolite and carbon- ceria were prepared and palladium was dispersed over them via impregnation method. The prepared samples were characterized by X-ray emission scanning electron diffraction （XRD）, field microscopy （FESEM）, Brunauer-Emmett-Teller surface area （BET）, Fourier transform infrared spectroscopy （FTIR） and thermogravi- metric （TG） techniques. Characterization of nanocatalysts revealed a good morphology with an average particle size in a nano range, and confirmed the formation ofnano-ceria with an average crystallite size below 60 nm. BET analysis indicated a considerable surface area for catalysts （-1000 m^2·g^-1）. FTIR patterns demonstrated that the surface groups of synthesized catalysts are in good agreement with the patterns of materials applied in catalyst synthesis. The performance of catalysts was assessed in a low-pressure catalytic oxidation pilot in the temperature range of 100℃-250℃. According to the reaction data, the synthesized catalysts have been shown to be so advantageous in the removal of volatile organic compounds （VOCs）, represent- ing high catalytic performance of 98% for the abatement of xylene at 250℃. Furthermore, a reaction network is proposed for catalytic oxidation of xylene over nanocata- lysts.
文摘将微波与湿式催化氧化技术相结合,以硫酸改性纳米氧化铈为催化剂,H2O2为氧化剂,降解腈纶废水。研究了催化剂和氧化剂的用量、反应时间、反应温度等因素对有机物去除率的影响,确定了最佳反应条件为50 m L腈纶废水(COD 635 mg/L)投加0.25 g酸化纳米Ce O2催化剂和0.3 m L 6%的H2O2,室温下搅拌3 h,微波辐射140℃下反应60 min,COD平均去除率达到89.7%。
