Direct conversion of CH 4 and O 2 to value-added chemicals is important for natural gas industries. However, challenges remain due to the difficulty of O 2 activation in forming active oxygen species for CH 4 activation under mild conditions.
Recently, a research group led by Prof. DENG Dehui, Assoc. Prof. CUI xiaoju and YU Liang from the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences (CAS) realized the electrochemical conversion of CH 4 by O 2 to HCOOH at room temperature. This study was published in Journal of the American Chemical Society .
The researchers developed a high-pressure electro-Fenton strategy to establish a hetero-homogeneous process for electro-catalytic conversion of CH 4 by O 2 at room temperature. They revealed that CH 4 was efficiently activated by ·OH, which was produced via a heterogeneous electroreduction of O 2 to H 2 O 2 on the Ag foil cathode, followed by a homogeneous Fe 2+ -facilitated H 2 O 2 decomposition.
Besides, the researchers found that the elevated pressure not only improved the productivity of H 2 O 2 from O 2 electro-reduction but also boosted the reaction collision probability between CH 4 and active ·OH in-situ generated from Fe 2+ -facilitated decomposition of H 2 O 2 .
Compared with the traditional electro-catalytic CH 4 conversion process with high overpotential (>0.9 V) and low Faradaic efficiency (< 60%), the high-pressure electro-Fenton process achieved an HCOOH Faradaic efficiency of 81.4% with an ultra-low cathodic overpotential of 0.38 V. The HCOOH productivity was 11.5 mmol h -1 gFe -1 , which was 220 times that of ambient pressure.
"This work provides a new way for energy-efficient and sustainable conversion of CH 4 by directly using O 2 under mild conditions," said Prof. DENG.
Journal of the American Chemical Society
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High-Pressure Electro-Fenton Driving CH4 Conversion by O2 at Room Temperature
26-Jan-2024