【摘要】 用程序升温反应原位红外跟踪法（TPR-IR）,程序升温表面反应法（TPSR）和程序升温表面反应原位红外跟踪法（TPSR-IR）研究了Ni/Al₂O₃,Ni/MgO催化剂的甲烷化反应。发现Ni/Al₂O₃催化剂的活性高于Ni/MgO催化剂,而后者的CO₂选择性远高于前者。通过观察程序升温反应过程中CO吸附态的动态行为,考察了催化剂活性中心的种类和性质,从表面键的角度分析了表面碳物种与活性中心的关系,认为担体对催化剂活性的影响在于改变了催化剂活性中心的种类和性质,担体改变CO₂产物的选择性可能是担体影响了金属中心上的两个竞争反应,其微观机制可能与CO₂由镍中心向MgO担体上的迁移有关。更多还原

【Abstract】 Temperature programmed reaction with in situ infrared spectroscopy tracing (TPR-IR), temperature programmed surface reaction (TPSR) and temperature programmed surface reaction with in situ infrared spectres-copy tracing (TPSR-IR) methods were used to investigate the methana-tion of CO on Ni/Al2O3 and Ni/MgO catalysts. It was observed that Ni/Al2O3 catalyst was more active for CO methanation than Ni/MgO catalyst, while the selectivity for CO2 formation of Ni/MgO catalyst was much higher than that of Ni/Al2O3 catalystThe properties of different active sites on the catalysts were determined by the observation of the dynamic behavior of chemisorbed CO during temperature programmed reaction. The correlation between surface carbon species and active sites was made from the surface bond viewpoint. It was proposed that the modification of catalyst activity by the supports is due to the changes in the types and properties of the active sites on the catalysts.From the facts that CO2 formation was affected by the supports, it was suggested that this might be originated from the influence of the supports on two competition reactions on the metal sites. And the migration of surface CO2 from the metal sites to the support MgO had bearing on the microscopic reaction mechanism.更多还原