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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/Al_2O_3,Ni/MgO催化剂的甲烷化反应。发现Ni/Al_2O_3催化剂的活性高于Ni/MgO催化剂,而后者的CO_2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CO_2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CO_2由镍中心向MgO担体上的迁移有关。
The catalytic performance of Ni / Al_2O_3 and Ni / MgO catalysts was investigated by using TPR-IR, TPSR and TPSR-IR. The reaction. It is found that the Ni / Al 2 O 3 catalyst is more active than the Ni / MgO catalyst, while the latter has much higher CO 2 selectivity than the former. By observing the dynamic behavior of the CO adsorption state during the temperature rising reaction, the types and properties of the active sites of the catalysts were investigated. The relationship between the surface carbon species and the active sites was analyzed from the perspective of the surface bond. The influence of the supports on the catalyst activity was changed The type and nature of the active center of the catalyst and the change of the selectivity of the CO 2 product by the support may be that the support affects two competitive reactions on the metal center. The microscopic mechanism may be related to the migration of CO 2 from the nickel center to the MgO support.