Ni/La_2O_3/α-Al_2O_3中的高温脱附氢促进CH_4/CO_2重整反应的初活性  

High Temperature Desorbed Hydrogen in Ni/La_2O_3/α-Al_2O_3 Improves the Initial Reaction Rate of CH_4/CO_2 Reforming

作　　者：崔月华[1] 徐恒泳[1] 葛庆杰[1] 毕亚东[1] 王玉忠[1] 侯守福[1] 李文钊[1] 

机构地区：[1]中国科学院大连化学物理研究所,辽宁大连116023

出　　处：《催化学报》2006年第8期659-663,共5页

摘　　要：通过H2程序升温脱附实验,在H2还原的Ni/La2O3/-αAl2O3催化剂上可以明显观察到高温脱附氢(高温氢).动力学实验结果表明,随催化剂上高温氢含量的增加,CH4/CO2重整反应的初始活性升高,同时高温氢也可在重整反应过程中原位生成,并使重整反应的活性最终达到稳定.脉冲实验结果表明,随催化剂上高温氢含量的增加,CH4解离后生成的活性中间体CHx物种的x值也增大,进而降低了CHx与CO2反应的活化能,提高了CHx与CO2反应的速率.La2O3助剂的添加提高了Ni/La2O3/-αAl2O3催化剂上逆水气变换反应的速率,并且对CO2的活化也有促进作用.La2O3助剂的加入对于CH4/CO2重整反应的重要作用是使高温氢的数量增多且稳定性提高,有利于保持CHx物种中较高的x值,促进重整反应.The hydrogen desorbed at high temperature （high-temperature hydrogen） over the hydrogen reduced catalyst Ni/La2O3/α-Al2O3 was observed by H2 temperature-programmed desorption. Kinetic experiments show that the activity of the reforming reaction is initially increased with the amount of high-temperature hydrogen in Ni/La2O3/α-Al2O3 and finally reaches a constant value due to the in situ generation of the high-temperature hydrogen. Pulse results indicate that the high-temperature hydrogen in Ni/La2O3/α-Al2O3 is prone to form CHx species with high x values, which has higher activity for the reaction of CHx with CO2. The Ni/La2O3/α-Al2O3 catalyst with plenty of high-temperature hydrogen can increase the x values of CHx species and decrease the activation energy for the reaction between CH, and CO2, leading to a higher reaction rate. The addition of La203 on the Ni/α-Al2O3 catalyst promotes the reverse water-gas shift reaction and slightly improves the activation of CO2. La2O3 also increases the amount of high-temperature hydrogen and its stability, resulting in higher x values of CHx species and improving the reforming reaction rate.

关 键 词：高温脱附氢 镍基催化剂 氧化镧 甲烷重整反应 初始速率 

分 类 号：O643.32[理学—物理化学]