Recent progress in morphological control of zeolites from organic templates

Zeolites have been widely applied in the fields of adsorption, ion exchange, and catalysis due to their uniform micropores, tunable active sites, high adsorption capacity, and excellent thermal and hydrothermal stability. Notably, due to the restricted diffusion of bulky guest molecules in micropores, the catalytic performances of conventional zeolites are strongly hindered. To solve this problem, it is suggested to control zeolite morphology to improve the mass transfer in the catalysis. In the past decades, many efforts have been made to develop novel strategies for control of zeolite morphologies. Typically, it was employed organic templates, which are critical for control of zeolite structure, space-filling, and charge-balancing. In the beginning, surfactants and polymers as organic templates were used. Later, the bifunctional organic templates were employed. More recently, small organic templates have been applied. As a result, zeolites with various morphologies such as nanosheets, nanoparticles, and nanoneedles have been successfully achieved, which greatly improve catalytic performances by enhanced mass transfer. In this review, they mainly focused on the use of organic templates to control zeolite morphologies of industrial zeolites such as MFI, *BEA, MOR, FER, FAU, TON, MTW, and AEI structures as well as potentially important applications of zeolite such as UWY structure.

However, despite great efforts for control of zeolite morphology from organic templates has been made in recent years, there are still many challenges to be solved. For examples, the role of organic templates for control of zeolite morphologies remains elusive; control of zeolite morphologies is easy in the laboratory, but it is difficult for commercialization at large scale; it is strongly desirable to control zeolite morphology from sustainable routes such as organotemplate-free, but it is limited. Therefore, sustainable synthesis of zeolites with controllable morphology at industrial scale provide a good opportunity for preparation of highly efficient zeolite catalysts in the future.