A mutually isolated nanodiamond/porous carbon nitride nanosheet hybrid with enriched active sites for promoted catalysis in styrene production

• Published in: Catalysis science & technology Vol. 1; no. 4; pp. 148 - 155
• Main Authors: Ge, Guifang, Guo, Xinwen, Song, Chunshan, Zhao, Zhongkui
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 24.02.2020
• Subjects: Biosensors; Carbon; Carbon nitride; Catalysis; Catalysts; Chemical bonds; Deactivation; Dehydrogenation; Diamonds; Dispersion; Drug delivery systems; Energy conservation; Energy consumption; Ethylbenzene; Iron oxides; Molten salts; Nanosheets; Optoelectronic devices; Organic chemistry; Oxidation; Styrenes
• ISSN: 2044-4753; 2044-4761
• DOI: 10.1039/c9cy02217a

Metal-free carbon-based materials have led to a great breakthrough in energy-saving styrene production via the direct dehydrogenation (DDH) of ethylbenzene in comparison to potassium-promoted iron oxide catalysts that suffer from severe coke formation, drastic deactivation and vast energy consumption. Owing to their unique structure and surface chemistry, nanodiamonds (NDs) have attracted a great deal of attention in heterocatalysis, including the catalytic DDH of ethylbenzene. However, incurable aggregation caused by existing surface forces and chemical bonding forces inevitably causes a deterioration in their catalytic performance due to the lowered accessibility of active sites. Herein, we, for the first time, report a facile two-step molten salt-oxidation approach to fabricate a mutually isolated ND/porous carbon nitride nanosheet hybrid with enriched surface ketonic C&z.dbd;O catalytically active sites (ND/CN-ms-o) through de-aggregating NDs and then inserting the well-dispersed NDs into in situ pore-making carbon nitride nanosheets (CNs) in molten salt (MS), followed by oxidation treatment in air. The resulting ND/CN-ms-o catalyst demonstrates 2.4 and 2.3 times higher steady-state styrene rates (7.06 mmol g −1 h −1 ) towards the direct dehydrogenation of ethylbenzene to styrene compared with pristine NDs (2.99 mmol g −1 h −1 ) and CNs (3.66 mmol g −1 h −1 ), respectively. Moreover, this work opens up a new horizon for fabricating other hybrids from dispersion-requiring carbonaceous parents with potential for diverse applications, including catalysis, drug delivery, biosensors, field-emission displays, optoelectronic devices, and chromatographic separation. A mutually isolated nanodiamond/porous carbon nitride nanosheet hybrid with enriched catalytic sites is fabricated by a facile two-step molten salt-oxidation strategy, generating an excellent catalyst for clean and energy-saving styrene production.