氧化镧催化剂上的低温甲烷氧化偶联反应

摘要

采用沉淀法制备了氧化镧催化剂,并考察其催化低温甲烷氧化偶联反应的性能. 催化剂性能测试结果表明,在723 K, CH4/O2摩尔比=3和GHSV=7 500 ml/(g·h)的条件下,甲烷的转化率和C2的选择性分别达26.6%和40.8%, 比商品化氧化镧催化剂的启动温度低100 K. 催化剂的表征结果表明,沉淀法制备的氧化镧催化剂与商品化的氧化镧催化剂都为六方晶相的氧化镧,但前者具有较大的比表面积,并且在598 K处出现一个明显的O2脱附峰.%The oxidative coupling of methane could take place at 723 K over the La2O3 catalyst prepared by the precipitation method, which was about 100 K lower than the startup temperature over the commercial La2O3 catalyst. Under the conditions of 723 K, CH4/O2 molar ratio of 3, and GHSV=7 500 ml/(g·h), the conversion of methane and selectivity for C2 hydrocarbons reached 26.6% and 40.8%, respectively. The characterization results showed that there was only hexagonal La2O3 over the two catalyst samples, but the catalyst prepared by precipitation had a larger specific surface area and a distinct desorption peak of adsorbed O2 at 598 K.