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采用气相化学沉积法对HZSM 5分子筛的外表面进行选择性修饰 ,然后将它作为载体制备Mo/HZSM 5催化剂 ,并应用于甲烷无氧脱氢芳构化反应 .改性的催化剂比未改性的催化剂表现出更好的甲烷转化活性、芳烃选择性和稳定性 ,明显地抑制了积碳的生成 .利用核磁氢谱对催化剂进行了表征 .在未经改性的Mo/HZSM 5催化剂表面 ,平均每个晶胞中含有 1 12个B酸中心 ,而在改性后的催化剂表面 ,平均每个晶胞中只有 0 6 1个B酸位 .说明在甲烷无氧芳构化反应中 ,少量的B酸中心即可达到反应要求 ,过多的酸性位只会导致更多积碳物种的生成 ,从而加快催化剂失活速度 ,降低其稳定性 .
The outer surface of HZSM 5 molecular sieve was selectively modified by vapor phase chemical deposition and then used as a carrier to prepare Mo / HZSM 5 catalyst for anaerobic dehydroaromatization of methane. The modified catalyst was less modified than unmodified Of the catalyst showed better methane conversion activity, aromatic selectivity and stability, significantly inhibited the formation of carbon deposition.The structure of the catalyst was characterized by 1H-NMR.On the unmodified Mo / HZSM 5 catalyst surface, The average number of B acid sites in each unit cell is 1 126, while on the modified catalyst surface, there are only 0 6 1 acid sites in each unit cell. Of the B acid center to meet the reaction requirements, too much acidic bit will only lead to the formation of more carbon-producing species, thereby accelerating the rate of catalyst deactivation and reduce its stability.