Fe/Fe₃ C Boosts H₂ O₂ Utilization for Methane Conversion Overwhelming O₂ Generation.

Area of Science:

• Heterogeneous catalysis
• Oxidation chemistry
• Materials science

Background:

• Hydrogen peroxide (H₂O₂) is a potent oxidant used in industry.
• Its decomposition often yields unwanted oxygen (O₂) instead of desired hydroxyl radicals (•OH).
• This competition leads to inefficient H₂O₂ usage and waste.

Purpose of the Study:

• To design and investigate novel Fe-based heterogeneous Fenton-type catalysts.
• To understand and control the competition between •OH generation and O₂ production from H₂O₂.
• To enhance the selective oxidation of methane using H₂O₂.

Main Methods:

• Fabrication of Fe-based catalysts with Fe-Nₓ sites and Fe/Fe₃C nanoparticles.
• Characterization of catalyst active sites (Fe-Nₓ in low spin state, Fe₃C).
• Evaluation of catalytic performance in methane oxidation and H₂O₂ decomposition pathways.

Main Results:

• Achieved 18% methane conversion with 96% selectivity for liquid oxygenates.
• Attained over 90% selectivity for formic acid.
• Successfully suppressed O₂ generation by 68% through catalyst design.
• Identified Fe₃C as promoting •OH generation and Fe⁰ nanoparticles as favoring O₂ production.

Conclusions:

• Finely tuned Fe-based catalysts, particularly those with Fe-Nₓ and Fe₃C, can efficiently utilize H₂O₂ for selective methane oxidation.
• Controlling the interplay between active sites minimizes H₂O₂ waste via O₂ suppression.
• This research offers a pathway for more efficient H₂O₂ application in the chemical industry.