Coupling dehydrogenation cracking and steam cracking with H2O generated by hydrogen selective combustion through sodium tungstate promoted zeolite–perovskite composites

The substantial energy consumption and high greenhouse gas emissions associated with steam cracking have driven the exploration of alternative methods for producing light olefins from naphtha. In this context, we propose a novel strategy that integrates dehydrogenation cracking with selective hydrogen combustion to enhance naphtha cracking. This approach synergizes two key processes: the carbenium ion pathway for dehydrogenation and cracking, and the radical cracking mechanism. Together, they enable the production of light olefins (C 2 = –C 3 = ) with unprecedented efficiency. Atom-planting introduces SnO x into the H-ZSM-5 surface and framework, providing favorable dehydrogenation active sites to promote the dehydrogenation cracking of n-octane. The loading of La and Mn onto Sn-ZSM-5 results in the formation of a LaMnO 3 perovskite structure, which promotes the selective combustion of hydrogen generated from Sn sites to produce H 2 O. Following the loading of Na 2 WO 4 , the generated H 2 O is triggered to form hydroxyl radicals, which subsequently induce the free radical cracking of n-octane. The Na 2 WO 4 /La-Mn/Sn-ZSM-5 system integrates the advantages of Sn-ZSM-5 and perovskite, enabling simultaneous dehydrogenation cracking and selective hydrogen combustion. Moreover, combined with the Na 2 WO 4 - promoted H 2 O - induced radical cracking, the system exhibits exceptional n-octane conversion and olefin production capacity.