Grape-Like Hierarchical Co/ZSM-5 Catalyst As a High-Performance Catalyst for Propane Dehydrogenation

Abstract— Cr- and Pt-based catalysts are the most widely used industrial catalysts for propane dehydrogenation (PDH). However, these catalysts still show disadvantages such as environmental toxicity and high economic cost. Cobalt (Co)-based catalysts have become promising candidate catalysts for PDH reactions due to their environmental friendliness and low cost. In this paper, Co-based catalysts are prepared by the impregnation method and precipitation method, respectively. The obtained catalysts all show grape-like nanocrystalline aggregated structures with intercrystallite mesopores and high surface area. This can improve the dispersion of Co species and mass transfer of catalysts. Comparing catalysts prepared by the two methods, the impregnated 1CoZI sample shows smaller CoO x nanoparticle size and higher Co 2+ /Co 3+ ratio than the precipitated 1CoZP sample. Moreover, the impregnated 1CoZI sample shows higher propane conversion and propylene selectivity, which is attributed to the smaller CoO x nanoparticle size and higher content of Co 2+ species bonded with zeolite framework. This structure brings higher catalytic activity and stability to the catalyst. Different PDH reaction conditions such as the reaction temperature and propane GHSV are also investigated. Under the optimal PDH reaction conditions (525°C and 4500 h –1 ), the impregnated 1CoZI shows high propane conversion (32%) and propylene selectivity (86%).