Unravelling Surface Basicity and Bulk Morphology of 2D Carbon-based Catalysts with Unique Dehydrogenation Performance

Activity and selectivity are key features at the basis of an efficient catalytic system for promoting one of the most important industrial processes at the heart of polymer synthesis: the steam- and oxygen-free dehydrogenation (DDH) of ethylbenzene (EB) to styrene (ST). The current industrial technology for ST production is a highly energy-demanding process that uses a large amount of steam and it is typically promoted by a K-Fe2O3 catalyst (K-Fe) at temperatures between 580 and 630 °C. Despite the general process feasibility, K-Fe lists the classical disadvantages of metal-based heterogeneous catalysts: a drastic deactivation/passivation due to the rapid generation of "coke" deposits and metal leaching or structural collapse occurring under harsh operative conditions. Carbon-based catalysts have emerged as valuable metal-free catalysts for DDH, offering superior performance in terms of activity and selectivity compared to the K-Fe system.[1] However, from the viewpoint of developing effective and sustainable metal-free catalysts for the DDH process, some key issues related to the complex puzzle of physicochemical and morphological properties of carbon nanomaterials still remain to be addressed.[2] In particular, the role of the surface basicity in N-doped carbons on the DDH selectivity and catalyst stability on stream, remains a matter of debate among the scientific community. This contribution sheds light on the complex structure-reactivity relationships of a class of highly microporous, N-rich Covalent Triazine Frameworks (sub-class of Porous Organic Polymers (POPs)) with superior activity and stability in DDH compared to benchmark metal-based and metal-free systems of the state-of-the-art, particularly under harsh operative conditions close to those used in industrial plants.[3]