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以La_2O_3为基础,碱土金属作为第二组分的二元氧化物催化剂均具有较高的生成C_2活性,特别是La-Ba-O系催化剂具有优良的甲烷氧化偶联活性和稳定性,当La/Ba原子比为2.5时,C_2收率可达20.3％。第三组分的添加有助于提高C_2选择性,特别是添加碱金属,可以抑制完全氧化反应,并提高乙烯/乙烷比。在La:Ba:Na=2.5:1:0.1的催化剂上进行了500/小时的寿命实验,在整个反应期间,催化剂的活性和选择性相当稳定。X-射线物相分析表明,新鲜催化剂除有少量的碳酸钡外,主要是氧化镧和氧化钡的混合物。500小时后的物相基本上是氧化镧和碳酸钡。使用前后催化剂的比表面积及表面La和Ba的分布均无改变。较高的CH_4/O_3比对提高C_2选择性有利,当CH_4:O_2=4:1时,C_2选择性和收率分别为65.1％和19.1％。
Binary oxide catalysts based on La 2 O 3 and alkaline earth metals as the second component all have higher activity of generating C 2. In particular, La-Ba-O based catalysts have excellent methane oxidative coupling activity and stability. When La / Ba atomic ratio of 2.5, C 2 yield of up to 20.3%. The addition of the third component helps to increase the C 2 selectivity, especially with the addition of alkali metals, which can inhibit the complete oxidation reaction and increase the ethylene / ethane ratio. Life tests of 500 hrs were carried out on La: Ba: Na = 2.5: 1: 0.1 catalyst, and the activity and selectivity of the catalyst were fairly stable throughout the reaction. X-ray phase analysis showed that the fresh catalyst was mainly a mixture of lanthanum oxide and barium oxide except for a small amount of barium carbonate. The phase after 500 hours is essentially lanthana and barium carbonate. Before and after use of the catalyst surface area and the distribution of La and Ba were unchanged. The higher CH_4 / O_3 ratio improved the selectivity of C_2, while the selectivity and the yield of C_2 were 65.1% and 19.1% when CH_4: O_2 was 4: 1.