Recent Progress in Metal-Molecular Sieve Catalysts for Propane Dehydrogenation

Abstract

Propane direct dehydrogenation (PDH) is an attractive technology for propylene production that has received extensive attention. Molecular sieves with uniform porous structure, high thermal stability, and unique confinement capability have been proven to be ideal supports for well-dispersed active sites to generate efficient PDH performance. In this review, we describe the progress in the synthesis and PDH performance of metal-molecular sieve catalysts, including metal-mesoporous silica, metal-zeolite, and metal-hierarchical zeolite catalysts. The strategies in identifying and regulating active site microstructure and metalmolecular sieve interactions as well as their correlations with active site structure and PDH mechanism are introduced simultaneously. Finally, the current limitations and future opportunities of metal-molecular sieve materials in the PDH reaction are also discussed. This review is expected to provide some guidance for future catalyst design based on utilizing the molecular sieve's structural confinement to facilitate propane activation and active site stabilization.

Regioselective Distribution of Zinc Hydroxyl within Straight Channels in MFI Zeolite Nanosheets for Propane Dehydrogenation

“…The high cost of Pt and toxicity of Cr motivate the exploration of noble-metal-free and environmentally friendly alternatives . In the last decades, the introduction of transition-metal sites within channels and skeleton of zeolites to form zeolite encapsulated transition-metal (TM@Zeolite) materials has achieved great success in alkane dehydrogenation. − The ordered subnanometric channels and the anchoring effect of the zeolite framework benefit the dispersion of active centers and prevent them from sintering, which are responsible for the exceptional PDH performance especially the catalytic lifetime and propylene selectivity . Moreover, in the case of M@Zeolite materials, zeolites provide various pores and cavities with different confinement effects.…”

Exploring the Properties of Silica Nanomaterials on Supporting Bimetallic PtZn Sites for Direct Propane Dehydrogenation

“…Propylene serves as a key raw material in the synthesis of various chemical compounds, including polypropylene, propylene oxide, and acrylonitrile. , Due to the rapid consumption of fossil fuels, conventional production, notably the fluid catalytic cracking and steam cracking of gas oil and naphtha, has lagged far behind the growing demand for propylene . With the incremental exploitation and utilization of shale gas, direct dehydrogenation of propane (PDH) has been recognized as one of the most promising methods for the production of propylene. − Nevertheless, catalysts for PDH still suffer deactivation caused by metal sintering and coke obscuring under high reaction temperatures and a reducing atmosphere.…”

“…With the incremental exploitation and utilization of shale gas, direct dehydrogenation of propane (PDH) has been recognized as one of the most promising methods for the production of propylene. − Nevertheless, catalysts for PDH still suffer deactivation caused by metal sintering and coke obscuring under high reaction temperatures and a reducing atmosphere. The occurrence of side reactions, such as cracking, hydrogenation, and coking, deteriorates active sites, reduces activity, compromises selectivity, and shortens durability. ,,− Therefore, the development of PDH catalysts with superior stability is absolutely imperative for the advancement of industrial propylene production.…”

Enhanced PtIn Catalyst via Ce-Assisted Confinement Effect in Propane Dehydrogenation

“…To date, Pt-based catalysts applied in the PDH field undergo deactivation caused by agglomeration in harsh reaction conditions and regeneration operation. − On the one hand, maintaining a good distribution of active sites is an important means to improve catalytic activity. Nevertheless, the smaller size of the active metal interface with the higher Gibbs surface energy resulted in it readily forming large particles via the Ostwald ripening mechanism or particle migration and coalescence in the reaction process. , Therefore, it is necessary to adopt rational strategies to enhance the structural stability of highly dispersed active sites, examples in our previous works by tuning support-metal interaction, zeolite structure evolution, and confinement. ,, As the reports of Yang et al, the strategy of using S atoms incorporated into the carbon (S–C) carrier and the formed strong chemical Pt–S interaction can help to reduce the free energy of surface-loaded platinum intermetallic nanoparticle, thereby maintaining uniform size distribution and ordered crystal structure at high temperature.…”