Mild Methane Electrochemical Oxidation Boosted via Plasma Pre-Activation

Area of Science:

• Electrochemistry
• Catalysis
• Plasma Science
• Chemical Engineering

Background:

• Partial methane oxidation (MOR) is challenging due to stable C-H bond activation and reaction pathway control.
• Existing industrial processes often require harsh conditions, leading to overoxidation and competing reactions.

Purpose of the Study:

• To develop a mild electrochemical method for partial methane oxidation (MOR).
• To synergistically activate and convert methane (CH4) into value-added oxygenates using a tandem plasma-electrocatalysis approach.

Main Methods:

• A real-time tandem process combining cascaded plasma and electrocatalysis was employed.
• Commercial Pd-based electrocatalysts were utilized under mild conditions (anode potential < 1.0 V vs. RHE).

Main Results:

• Achieved boosted CH4 conversion into alcohols, carboxylates, and ketones.
• Demonstrated mitigation of overoxidation and competing reactions due to mild operating conditions.
• Identified the crucial role of Pd(II) sites and surface hydroxyls in facilitating CH4 conversion.

Conclusions:

• A novel reaction mechanism involving coupling reactions of adsorbed hydroxyls, CO, and C1/C2 alkyls was established.
• Pre-activation of methane is key to enhancing electrochemical partial MOR under mild conditions.
• This work offers a sustainable pathway for CH4 conversion technology development.