Mesoporous and Graphitic Carbide-Derived Carbons as Selective and Stable Catalysts for the Dehydrogenation Reaction

Dehydrogenation of ethylbenzene to styrene is one of the most important catalytic processes in chemical industry. While it was demonstrated that nanocarbons like nanotubes, nanodiamond, or nanographite show high performance, especially selectivity, these powders give rise to handling problems, high pressure drop, hampered heat and mass transfer, and unclear health risks. More common macroscopic carbon materials like activated carbons show unsatisfying selectivity below 80%. In this study, mesoporous, graphitic, and easy to handle carbon powders were synthesized on the basis of the reactive extraction of titanium carbide in a novel temperature regime. This resulted in extraordinary properties like a mean pore diameter of up to 8 nm, pore volumes of up to 0.90 mL g –1, and graphite crystallite sizes exceeding 25 nm. Exceptional styrene selectivities of up to 95% were observed for materials synthesized above 1300 °C and pretreated with nitric acid. Furthermore, the long-term stability of these non-nanocarbon catalysts could be demonstrated for the first time during 120 h of time-on-stream.