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自制硫代钼酸铵经热分解所得的硫化钼催化剂有较好的甲烷化活性,但衰减亦较快。本文对反应前后的催化剂及试剂MoS_2进行了IR、LRS、TEM、XPS、XFA、ESR等分析测试,证明了使用后的催化剂中,辉钼矿的晶粒长大,晶型变好,未发现碳的沉积。实验还发现了催化剂中高价钼及硫链的存在,而在反应后均减少或消失,硫钼比降低。本文对上述变化与催化剂活性衰减之间的关系作了分析,认为辉钼矿晶粒的长大以及样品中硫钼原子比的降低,是催化剂活性衰减的两个重要原因。并由此推测硫化钼催化剂上的甲烷化反应是通过双活性中心而进行的。
The self-made ammonium thio-molybdate thermal decomposition of molybdenum sulfide catalyst has better methanation activity, but also decay faster. In this paper, IRS, LRS, TEM, XPS, XFA, ESR and other catalysts have been tested before and after the reaction. It is proved that the molybdenite grains grow up and the crystal form becomes better in the catalyst after use. Carbon deposition. The experiment also found the presence of expensive molybdenum and sulfur chains in the catalyst, but all decreased or disappeared after the reaction, and the ratio of sulfur to molybdenum decreased. In this paper, the relationship between these changes and the decay of catalyst activity was analyzed. It is considered that the growth of the molybdenite grains and the reduction of the atomic ratio of sulfur and molybdenum in the samples are two important reasons for the decay of the catalyst activity. It was therefore speculated that the methanation reaction over the molybdenum sulfide catalyst proceeded through the bifunctional site.