摘要
用机械混合法制备了ZnO/HZSM 5丙烷芳构化催化剂 .X射线衍射与透射电镜测试结果表明 ,沸石表面的ZnO在焙烧后发生了分散和迁移 .稀盐酸对沸石表面锌的反交换实验结果表明 ,有部分锌迁入沸石孔道并与沸石表面发生了相互作用 .用X射线光电子能谱和吡啶吸附的红外光谱技术对ZnO/HZSM 5进行了表征 ,结果进一步表明有部分ZnO与HZSM 5发生固相离子交换反应 .对HZSM 5和ZnO/HZSM 5催化剂的丙烷芳构化活性进行了评价 。
The ZnO/HZSM-5 catalyst for propane aromatization was prepared by mechanically mixing ZnO with HZSM-5. XRD and TEM investigations demonstrated that ZnO located on the external surface of the zeolite crystals can migrate from outside to inside of the channels during calcination, and zinc species are highly dispersed. The migration of zinc species was confirmed by a back-exchange experiment in which the zinc-containing samples were treated by a dilute hydrochloric acid solution, and the experimental results showed that the interaction between zinc species and zeolite surface occurred. The catalyst was characterized. by XPS and IR spectroscopy. It can be seen that only small part of ZnO in the ZnO/HZSM-5 catalyst reacts with the protons of HZSM-5 Bronsted acid sites through solid state ion exchange. The conversion of propane to aromatics over the ZnO/HZSM-5 catalyst was evaluated in a fixed-bed continuous flow reactor and the results indicated that the aromatic selectivity can be improved significantly by introducing promoter zinc by mechanically mixing ZnO with HZSM-5.
出处
《催化学报》
SCIE
CAS
CSCD
北大核心
2001年第3期229-232,共4页
