Na-W-Mn/SiO_2催化剂的原位XRD研究

Investigation of in-situ XRD of Na-W-Mn/SiO_2 catalyst

制备了Na-W-Mn/SiO_2催化剂,研究了Mn(NO_3)_2/SiO_2,Na_2WO_4·2H_2O,Na_2WO_4/SiO_2,Na-W-Mn/SiO_2催化剂的晶形结构,并采用MAUD软件对不同反应温度下Na-W-Mn/SiO_2催化剂的XRD数据进行了模拟计算,分析了主要组分的物相组成,研究了催化剂上各物种在不同温度下的原位XRD动态变化及其相互作用,并用同步辐射原位XRD法研究了甲烷氧化偶联制乙烯反应过程中,Na-W-Mn/SiO_2催化剂结构的实时变化及反应产物的变化。实验结果表明,催化剂在不同温度下以不同的晶型结构形式存在,W,Mn物种是影响催化剂晶型结构变化的重要因素,Na-W-Mn/SiO_2催化剂在850℃的晶体结构具有甲烷氧化偶联制乙烯的催化活性。

The catalyst Na-W-Mn/SiO2 was prepared,In-situ XRD experiments of the catalysts consisting of different components with the temperature changing were designed,the crystal structure of Mn（NO3）2/SiO2,Na2WO4·2H2O,Na2WO4/SiO2,Na-W-Mn/SiO2 were researched.Furthermore the simulation of XRD patterns of the catalyst Na-W-Mn/SiO2 under different temperature were calculated by MAUD software.The main phase components were analyzed.Dynamic change and the mutual interaction of species under different temperature were researched by in-situ XRD method.Synchrotron In-situ XRD methods were used to follow the structural changes that occur during the OCM reaction of CH4 and O2 over Na-W-Mn/Si O2.Experimental results show there exist different crystal structure of the catalysts under different temperature.The elements of W and Mn are the key factors to affect the crystal structure changing of the catalysts,moreover the crystal structure under850℃be of OCM catalytic activity.