Petroleum pitch-derived porous carbon as a metal-free catalyst for direct propane dehydrogenation to propylene

Propane dehydrogenation (PDH), as one of the most promising strategies for propylene synthesis, has attracted tremendous attention with the increase of shale gas exploitation. The exploration of green and sustainable catalytic materials to replace the high-price (Pt-Sn/Al2O3) and environmentally unfavorable (Cr2O3/Al2O3) catalysts will drive the rapid development of PDH technology. Porous carbon-based materials have been proposed as ideal PDH catalysts due to their abundant surface quinone/ketone CO groups for C-H bond activation and well-developed pore structures for mass transfer. However, the facile preparation of carbon-based catalysts with controllable surface properties and unique architectures remains a challenge. And the structure-function relationship of carbon-based catalysts in PDH is also under debate. Herein, we report a simple and efficient synthetic method to prepare the porous carbon-based PDH catalysts with cheap and readily available petroleum pitch as carbon source. The surface chemical properties and architectures of the porous carbon-based catalysts can be precisely tailored by varying the activation temperature during the synthesis process. Various characterizations including X-ray photoelectron spectra, temperature-programmed pyrolysis curves, thermogravimetric analysis and morphology observations clarify that the plentiful surface quinone/ketone CO groups and appropriate adsorption/desorption strengths of reactant/products derived from the great specific surface area are vital factors that guarantee the excellent C-H bond activation capability (propane conversion 45.6%) and alkenes selectivity (73.9%, propylene and ethylene) of the petroleum pitch-derived porous carbon catalyst. This work not only provides a promising alternative catalyst for the PDH process but also enriches the application fields of the carbon-based catalysts.