【摘要】 采用溶胶-凝胶法制备BaO·6Al2O3系列催化剂.考察了Ba、Mn的引入对Al2O3的热稳定性及甲烷催化燃烧性能的影响.结果表明,Ba在高温下与Al2O3首先生成BaAl2O4,然后进一步与Al2O3反应生成具有β-Al2O3结构的BaAl12O19六铝酸盐,抑制了Al2O3进一步的烧结,提高了催化剂的热稳定性.Mn的引入也能够促进六铝酸盐的生成并提高催化剂的甲烷燃烧活性.采用超临界干燥法可抑制干燥过程中因毛细收缩引起的比表面积降低.所制备的BaMnAl11O19催化剂经1200℃焙烧4h后,比表面积为35.1m2·g-1,在空速40000h-1条件下,10%甲烷转化温度(T10%)为500℃,催化活性明显高于常规干燥法制备的相应催化剂.更多还原

【Abstract】 A sol-gel method was employed to prep are Mn-substi tuted barium hexaalum inate catalysts for methane combustion.Supercritical dry ing(SCD)and conventional oven drying(CD)methods were used to ex-tract the w ater in the hydrogel.The e ffects of drying methods,as well as t he incorporat ion of Ba,Mn,on properties of the catalysts were inv estigated by means of N 2-adsorption,TG-DTA and X-ray diffr action.The supercritical dryin g method could maintain a higher specific surface area of the samples and suppre ss the tra ns-formation intoá-Al 2 O 3 at elevated temperature s.The intro duction of Mn oxides could promote th e transformation into hexaalu minates during calcination.BaMnAl 11 O 19 catalyst dried by SC D method has a specific surface area of 35.1m 2 穏-1 and an activity with T 10% (temperature for 10%methane convers ion)of 500℃under the condition of 0.1MPa and 40000h-1 GHSV.更多还原