Role of hydroxyl groups of Zn-containing nanosized MFI zeolite for the photocatalytic oxidation of methane at room temperature in water

• Published in: ChemSusChem 2024-11
• Main Authors: Piva, Diógenes, Fang, Geqian, Ghojavand, Sajjad, Dalena, Francesco, Alhajjar, Nour, de Waele, Vincent, Ordomsky, Vitaly, Khodakov, Andrei, Tayeb, Karima Ben, Fernandes, Tiago, Mintova, Svetlana
• Format: Article
• Language: English
• Subjects: Chemical Sciences
• ISSN: 1864-5631; 1864-564X
• DOI: 10.1002/cssc.202401656

Effective conversion of methane to a mixture of more valuable hydrocarbons and hydrogen under mild conditions is a great scientific and practical challenge. Here, we synthesized Zn-containing nanosized MFI zeolite for direct oxidation of methane in water using only oxygen as the oxidant under mild light irradiation at room temperature. The formation of the surface hydroxyl groups on nanosized MFI-type zeolite and their disappearance in the Zn-containing nanosized MFI zeolite were confirmed with infrared Fourier transform (FTIR) spectroscopy. Incorporation of atomically dispersed zinc atoms into the framework of nanosized MFI zeolite is revealed by Nuclear Magnetic Resonance and X-ray Photoelectron Spectroscopy. Unexpectedly, pure silica MFI zeolite exhibited the highest photocatalytic performance. Our finds demonstrated that large number of isolated silanol groups and silanol nests enhanced productivity of oxygenate compounds and C 2 H 6 , while the Zn incorporated into the zeolite framework or attached to the silanol nests of the nanosized zeolites are less efficient. A mechanism of photocatalytic methane oxidation is proposed. These findings provide insights into developing active nanosized zeolite photocatalysts with extended amount of surface hydroxyl groups that can play a key role in photocatalytic methane conversion.