摘要
采用氨水调节钼酸铵浸渍液的pH值,调变了钼物种在水溶液中的聚集状态,将常规浸渍液中体积较大的多聚钼阴离子(Mo7O246-或H2Mo7O244-)解离成较小的单聚钼阴离子(MoO42-)形式,使其能够有效地扩散进入分子筛的孔道中,从而制备出高分散的Mo/HMCM-49催化剂.该催化剂在甲烷脱氢芳构化反应中表现出了更好的催化性能,具有高的甲烷转化率和苯生成速率.
Mo/HMCM-49 catalyst with highly dispersed MoOx species was prepared by adding ammonia solution to the ammonium heptamolybdate aqueous solution during the impregnation process.The ammonia mediated the pH value of the impregnation solution,altered the aggregation state of Mo species.Compared with the large Mo7O246-/H2Mo7O244-species which are predominantly presented in the conventional impregnation solution,the monomer MoO42-formed in ammonia solution could efficiently diffuse into the micropores and/or channels of the HMCM-49,resulting in a higher dispersion of Mo species.Consequently,the resultant Mo/HMCM-49 catalyst exhibited significantly enhanced performance for MDA reaction with higher methane conversion and benzene formation rate.
出处
《汕头大学学报（自然科学版）》
2010年第3期52-57,65,共7页
Journal of Shantou University：Natural Science Edition
