The effect of active site distribution in bi-functional Pt-zeolite catalysts for ethane dehydroaromatization

[Display omitted] •Pt/ZSM-5 catalysts with different porosity and metal distribution were synthesized.•The catalysts were tested for direct dehydroaromatization of ethane.•The distribution of acid and metal active sites had a large effect on activity.•Adjacent active sites situated inside ZSM-5 resulted in the highest yield of aromatics. The direct conversion of ethane to higher-valued petrochemical feedstock such as benzene, toluene and xylenes (BTX) has become more economically attractive because of the recent shale gas revolution. The selectivity towards BTX and catalyst deactivation represent significant technical challenges in this process. In this work, we synthesized a series of bi-functional Pt on acidic ZSM-5 catalysts to investigate the effect of platinum nanoparticle distribution and location on selectivity and deactivation. The best catalyst was Pt encapsulated in desilicated ZSM-5 that remained stable after 15 h of reaction resulting in 60% higher conversion and 75% higher BTX selectivity than Pt supported on conventional acidic ZSM-5 zeolite.