用常压高频冷等离子体射流还原Ni/γ-Al_2O_3催化剂的新方法  

A Novel Reduction Method for Ni/γ-Al_2O_3 Catalyst by a High Frequency Cold Plasma Jet at Atmospheric Pressure

作　　者：刘改焕[1] 储伟[1] 龙华丽[1] 戴晓雁[1] 印永祥[1] 

机构地区：[1]四川大学化工学院,四川成都610065

出　　处：《催化学报》2007年第7期582-584,共3页

基　　金：国家自然科学基金(10475060);国家重点基础研究发展计划(973计划;2005CB221406).

摘　　要：采用大气压高频冷等离子体炬,对用于甲烷和CO2重整反应的Ni/γ-Al2O3催化剂进行还原.考察了还原后催化剂的反应活性和选择性,并与常规方法还原的催化剂进行了对比.结果表明,采用这种新方法还原催化剂只需10 min,操作快速简便,并且还原后的催化剂的活性和选择性都明显优于常规催化剂.在850℃,原料气CH4和CO2的摩尔比为4/6的条件下反应时,可获得95.77%的甲烷转化率、75.65%的CO2转化率、100%的H2选择性和94.79%的CO选择性.此外,该新型催化剂具有较好的稳定性,连续反应36 h后,活性基本不下降.XRD表征结果发现,采用该方法还原的催化剂只有金属镍和γ-Al2O3相,没有检测到Ni Al2O4以及其它镍氧化物.与常规催化剂相比,采用等离子体还原的新型催化剂具有较小的镍晶粒尺寸,金属活性组分的分散度大大提高.The Ni/γ-Al2O3 catalyst was reduced by high frequency cold plasma jet at atmospheric pressure. The performance of the catalyst for carbon dioxide reforming of methane was investigated. The process of catalyst reduction with plasma was quick and simple and was completed in only 10 min, giving activity and selectivity higher than those of the catalyst prepared by the conventional method. At the CH4/CO2 molar ratio of 4/6 and the reaction temperature of 850 ℃, the methane conversion and CO2 conversion reached up to 95.77% and 75.65 %, respectively, and a hydrogen selectivity of 100 % and a CO selectivity of 94.79 % were obtained over the novel catalyst reduced by plasma. The novel catalyst exhibited good stability during a reaction test for 36 h. XRD characterization showed that only a metallic nickel phase and γ-alumina existed in the catalyst reduced by plasma, and the NiAl2O4 phase and other nickel oxides were not detected. The nickel particle size of the catalyst was smaller than that of the conventional catalyst. An enhanced dispersion was achieved with the plasma reduction.

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

分 类 号：O643.36[理学—物理化学]