The Second Youth of a Metal-Free Dehydrogenation Catalyst: when γ-Al2O3 Meets Coke Under Oxygen and Steam-Free Conditions

The role of carbonaceous deposits (coke) formed in dehydrogenation catalysis has been extensively investigated over the last decades mainly with respect to the deactivation of metal-based and metal-free heterogeneous catalysts. Although much less emphasized, coke deposits grown on selected metal-oxides have also been described as active and selective phases for the alkenes dehydrogenation under oxidative or non-oxidative atmosphere. This work describes the straightforward preparation of “coked” γ-Al2O3-composites and their unprecedented catalytic performance in the ethylbenzene (EB) direct dehydrogenation (DDH) to styrene (ST) under steam- and oxygen-free conditions. The study unveils the effective potentiality of a catalytic system already known to the scientific community but never employed for the EB DDH under severe conditions, close to those commonly used in industrial plant (600 °C, 10 vol.% EB/He, GHSV = 3000 h-1). Such a simple catalytic system has revealed a remarkable stability on long-term tria...