采用自制线管式介质阻挡放电反应器,针对非热等离子体协同Mn-Ce/La/γ-Al_2O_3催化剂对低浓度甲苯的去除开展研究。研究中制备了Mn/γ-Al_2O_3、Mn-Ce/γ-Al_2O_3、Mn-La/γ-Al_2O_3催化剂,从甲苯去除率、产物O_3生成、CO_x选择性及其...采用自制线管式介质阻挡放电反应器,针对非热等离子体协同Mn-Ce/La/γ-Al_2O_3催化剂对低浓度甲苯的去除开展研究。研究中制备了Mn/γ-Al_2O_3、Mn-Ce/γ-Al_2O_3、Mn-La/γ-Al_2O_3催化剂,从甲苯去除率、产物O_3生成、CO_x选择性及其他副产物生成情况考察比较了空管放电、协同催化剂放电时催化降解甲苯性能,并对催化剂进行了BET、SEM、H2-TPR和ICP-OES表征研究。结果表明:稀土助剂的加入有助于提高甲苯去除率及降低程度,且La催化性能优于Ce.,当外加电压22 k V、气量6 L·min-1、甲苯初始浓度600 mg·m-3时,Mn-La/γ-Al_2O_3催化剂对甲苯去除率达到72.74%。H2-TPR结果表明,稀土助剂的加入提高了催化剂低温活性及储氧能力,添加La的效果优于Ce。催化剂有助于抑制副产物O_3生成,提高CO_2和COx选择性。展开更多
A La-modified Al2O3 catalyst was prepared with deposition-precipitation method. The effect of calcination temperature on the reactivity for vapor phase hydrofluorination of acetylene to vinyl fluoride. The catalysts c...A La-modified Al2O3 catalyst was prepared with deposition-precipitation method. The effect of calcination temperature on the reactivity for vapor phase hydrofluorination of acetylene to vinyl fluoride. The catalysts calcined at different temperatures were characterized using NH3-TPD, pyridine-FTIR, X-ray diffraction, and Raman techniques. It was found that the calcination process could not only change the structure of these catalysts but also modify the amount of surface acidity on the catalysts. The catalyst calcined at 400 ℃ exhibited the highest conversion of acetylene (94.6%) and highest selectivity to vinyl fluoride (83.4%) and lower coke deposition selectivity (0.72%). The highest activity was related to the largest amount of surface acidity on the catalyst, and the coke deposition was also related to the total amount of surface acidic sites.展开更多
为了降低Ca Ti O3-(La,Nd)Al O3(简称CT-LNA)陶瓷的烧结温度和提高其介电性能,研究纳米Al2O3对Ca Ti O3-(La,Nd)Al O3陶瓷的烧结温度和介电性能的影响。固相法制备粉料,采用XRD和SEM分析其晶相和显微结构,用网络分析测试样品的介...为了降低Ca Ti O3-(La,Nd)Al O3(简称CT-LNA)陶瓷的烧结温度和提高其介电性能,研究纳米Al2O3对Ca Ti O3-(La,Nd)Al O3陶瓷的烧结温度和介电性能的影响。固相法制备粉料,采用XRD和SEM分析其晶相和显微结构,用网络分析测试样品的介电参数,结果表明,纳米Al2O3可促进陶瓷烧结,在1320~1400℃范围内可烧结成瓷,并具有较好的微波介电性能。当纳米Al2O3含量为50 wt%时,陶瓷在1340℃烧结可获得优良的微波介电性能:介电常数为42.6,Q×f值高达34,000GHz,频率温度系数为+4.8 ppm/℃。展开更多
文摘采用自制线管式介质阻挡放电反应器,针对非热等离子体协同Mn-Ce/La/γ-Al_2O_3催化剂对低浓度甲苯的去除开展研究。研究中制备了Mn/γ-Al_2O_3、Mn-Ce/γ-Al_2O_3、Mn-La/γ-Al_2O_3催化剂,从甲苯去除率、产物O_3生成、CO_x选择性及其他副产物生成情况考察比较了空管放电、协同催化剂放电时催化降解甲苯性能,并对催化剂进行了BET、SEM、H2-TPR和ICP-OES表征研究。结果表明:稀土助剂的加入有助于提高甲苯去除率及降低程度,且La催化性能优于Ce.,当外加电压22 k V、气量6 L·min-1、甲苯初始浓度600 mg·m-3时,Mn-La/γ-Al_2O_3催化剂对甲苯去除率达到72.74%。H2-TPR结果表明,稀土助剂的加入提高了催化剂低温活性及储氧能力,添加La的效果优于Ce。催化剂有助于抑制副产物O_3生成,提高CO_2和COx选择性。
基金The project was supported by the National Natural Science Foundation of China(21173153)Opening Project of Key Laboratory of Green Catalysis of Sichuan Institutes of High Education,China(LYY1101)~~
基金ACKNOWLEDGMENT This work was supported by the National Natural Science Foundation of China (No.20873125),
文摘A La-modified Al2O3 catalyst was prepared with deposition-precipitation method. The effect of calcination temperature on the reactivity for vapor phase hydrofluorination of acetylene to vinyl fluoride. The catalysts calcined at different temperatures were characterized using NH3-TPD, pyridine-FTIR, X-ray diffraction, and Raman techniques. It was found that the calcination process could not only change the structure of these catalysts but also modify the amount of surface acidity on the catalysts. The catalyst calcined at 400 ℃ exhibited the highest conversion of acetylene (94.6%) and highest selectivity to vinyl fluoride (83.4%) and lower coke deposition selectivity (0.72%). The highest activity was related to the largest amount of surface acidity on the catalyst, and the coke deposition was also related to the total amount of surface acidic sites.
文摘为了降低Ca Ti O3-(La,Nd)Al O3(简称CT-LNA)陶瓷的烧结温度和提高其介电性能,研究纳米Al2O3对Ca Ti O3-(La,Nd)Al O3陶瓷的烧结温度和介电性能的影响。固相法制备粉料,采用XRD和SEM分析其晶相和显微结构,用网络分析测试样品的介电参数,结果表明,纳米Al2O3可促进陶瓷烧结,在1320~1400℃范围内可烧结成瓷,并具有较好的微波介电性能。当纳米Al2O3含量为50 wt%时,陶瓷在1340℃烧结可获得优良的微波介电性能:介电常数为42.6,Q×f值高达34,000GHz,频率温度系数为+4.8 ppm/℃。