Na_(2)WO_(4)-Mn_(x)O_(y)/BaTiO_(3)催化剂的制备及其在甲烷氧化偶联反应中的应用

Preparation of Na_(2)WO_(4)-Mn_(x)O_(y)/BaTiO_(3) catalyst and its application in oxidative coupling of methane

采用浸渍法制备了Na_(2)WO4-Mn_(x)O_(y)/BaTiO_(3)催化剂,研究了Na_(2)WO_(4)-Mn_(x)O_(y)/BaTiO_(3)催化剂对甲烷氧化偶联反应(OCM)的影响,利用SEM,XRD,EDS等分析方法对催化剂进行表征,并与Na_(2)WO_(4)-Mn_(x)O_(y)/SiO_(2)催化剂进行对比。实验结果表明,Na_(2)WO_(4)-Mn_(x)O_(y)/BaTiO_(3)催化剂的活性组分W和Mn在钛酸钡表面分布均匀,且反应过程中催化剂的结构基本保持不变,在反+应温度为800℃、甲烷与氧气摩尔比为1.5时,Na_(2)WO_(4)-Mn_(x)O_(y)/BaTiO_(3)催化剂催化OCM反应的C_(2)收率约为19%,C_(2)^(+)收率约为21%。与Na_(2)WO_(4)-Mn_(x)O_(y)/SiO_(2)催化剂相比,Na_(2)WO_(4)-Mn_(x)O_(y)/BaTiO_(3)催化剂的反应起活温度低60℃,具有更加活泼的活性氧位,能够在更低的温度条件下开始OCM反应。

The Na_(2)WO_(4)-Mn_(x)O_(y)/BaTiO_(3) catalyst was prepared by impregnation method.The effect of Na_(2)WO_(4)-Mn_(x)O_(y)/BaTiO_(3) catalyst on the oxidative coupling of methane(OCM)was studied.The catalyst was characterized by SEM,XRD,EDS,and compared with Na_(2)WO_(4)-Mn_(x)O_(y)/SiO_(2) catalyst.The experimental results show that the active components of the Na_(2)WO_(4)-Mn_(x)O_(y)/BaTiO_(3) catalyst,W and Mn are uniformly distributed on the surface of barium titanate,and the structure of the catalyst remains basically unchanged during the reaction.At a reaction temperature of 800℃ and a molar ratio of methane to oxygen of 1.5,the C_(2) yield of the OCM reaction catalyzed by the Na_(2)WO_(4)-Mn(x)O_(y)/+BaTiO_(3) catalyst is about 19%,and the C_(2) yield is about 21%.Compared with the Na_(2)WO_(4)-Mn_(x)O_(y)/SiO_(2) catalyst,the activation temperature of the Na_(2)WO_(4)-Mn_(x)O_(y)/BaTiO_(3) catalyst is 60℃ lower,and it has more active oxygen sites,enabling it to start the OCM reaction at lower temperature conditions.