The catalytic conversion of methane to value-added liquid C1 oxygenates represents a promising pathway for the valorization of natural gas. However, the low polarizability of methane and its high C–H bond energy (439 kJ mol-1) render efficient and selective C–H bond activation and conversion challenging. Although high temperatures are generally required to drive the reaction, they also make methane prone to over-oxidation, producing carbon dioxide, a greenhouse gas. Hence, achieving efficient methane activation and selective conversion under mild conditions remains a critical challenge in this field.
Schematic illustration of room-temperature methane oxidation over Pd-MOR and a comparison of catalytic activities for different catalysts. (Image by DAI Xinyao)
In a study published in the Journal of the American Chemical Society, a team led by Prof. DENG Dehui, Associate Prof. LIU Yanting, and Prof. YU Liang from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) has realized room-temperature conversion of methane with ozone over MOR lattice-confined Pd sites. This catalytic system exhibits > 99% selectivity toward C1 oxygenates with a high yield of 6.0 mmol gPd-1 h-1 at 25 °C.
The researchers demonstrated that the lattice-confined Pd sites in MOR activate ozone to generate reactive oxygen species (O*), which can activate methane to yield the desired C1 oxygenates at room temperature. Furthermore, they found that dual-Pd sites outperform single-Pd sites, which is ascribed to an optimal trade-off between ozone dissociation to O* and C–H bond cleavage activities, thereby enabling efficient methane conversion.
“This work provides a new strategy for designing catalytic processes to develop efficient catalysts for low-temperature C–H bond activation”, said Prof. DENG.
Link:
https://pubs.acs.org/doi/10.1021/jacs.6c00561
https://www.dicp.ac.cn/xwdt/kyjz/202605/t20260520_8206413.html
