常压高频冷等离子体炬制备的CH_4/CO_2重整用Ni/γ-Al_2O_3催化剂的表征  

Characterization of Ni/γ-Al_2O_3 Catalyst Prepared by Atmospheric High Frequency Cold Plasma Jet for CO_2 Reforming of CH_4

作　　者：柴晓燕[1] 尚书勇[1,2] 刘改焕[1,3] 陶旭梅[1] 李祥[1,4] 白玫瑰[1] 戴晓雁[1] 印永祥[1] 

机构地区：[1]四川大学化工学院等离子体应用研究中心,四川成都610065 [2]宜宾学院化学与化工学院,四川宜宾644007 [3]中国石油工程公司西南分公司,四川成都610017 [4]西南科技大学理学院,四川绵阳621010

出　　处：《催化学报》2010年第3期353-359,共7页

基　　金：国家自然科学基金(19935010;10475060)

摘　　要：分别采用常规焙烧还原(C)、常规焙烧与常压高频冷等离子体炬还原相结合(PR),以及常压高频冷等离子体炬直接焙烧还原(PC&R)制备了Ni/γ-Al2O3催化剂.通过X射线衍射、H2-程序升温脱附、CO2-程序升温脱附、N2吸附-脱附实验、透射电镜和热重分析等方法对催化剂进行了表征.并考察了其CH4/CO2重整反应活性.结果表明,催化剂经等离子体处理后低温活性明显增加.在得到相同CH4和CO2转化率情况下,PC&R法制备的催化剂与常规催化剂相比,反应所需温度可以降低50oC.PC&R催化剂上Ni分散度提高了100%,Ni粒子粒径降低了70%,达到5nm,催化剂的抗积炭性能显著增强.所得催化剂较高的低温活性和抗积炭性能得益于常压高频冷等离子体炬对催化剂前驱体还原速率快,处理时间大为缩短,避免了由于长时间高温焙烧和还原所引起的对载体的烧结和金属Ni的团聚.A series of Ni/γ-Al2O3 catalysts were prepared by the conventional calcination and thermal reduction method （C）, conventional calcination and atmospheric high frequency cold plasma jet reduction method （PR）, and atmospheric high frequency cold plasma jet calcina- tion and reduction method （PC＆R）. CO2 reforming of CH4 was adopted to evaluate the performance of the Ni/γ-Al2O3 catalysts. The results showed that the catalyst prepared by PC＆R exhibited better low-temperature activity for CO2 reforming of CH4. At the same conversions of CH4 and CO2, the reaction temperature of the catalyst prepared by PC＆R was 50 oC lower than that of the catalyst by the conventional method. The samples were analyzed by X-ray powder diffraction, temperature-programmed desorption with H2 and CO2, N2 adsorp- tion-desorption, transmission electron microscopy, and thermogravimetric analysis. Compared with the conventional catalyst, the nickel dispersion of the Ni/γ-Al2O3 catalyst prepared by PC＆R was enhanced by 100%, Ni particle size about 5 nm on catalyst surface was decreased by 70%, and coking resistance was also improved significantly. The excellent low-temperature activity and structure of the catalysts by PC＆R were attributed to short treatment time during the plasma process instead of several hours in conventional calcination for decomposing and reducing the catalyst precursor of Ni（NO3）2/γ-Al2O3, which effectively avoided sintering and plugging.

关 键 词：常压高频冷等离子体炬 镍 氧化铝 负载型催化剂 甲烷 二氧化碳 重整 

分 类 号：O643.36[理学—物理化学]