Boosting Formic Acid Production in Methane Oxidation by Zeolite Confined Single-Site Rh Catalyst

Area of Science:

• Catalysis
• Materials Science
• Chemical Engineering

Background:

• Selective methane oxidation to oxygenates is challenging due to low reactivity and selectivity.
• Existing catalysts struggle with efficient single-pass methane conversion and product differentiation.

Purpose of the Study:

• To develop a highly selective catalyst for methane oxidation to value-added oxygenates.
• To investigate the mechanism of methane activation and product formation.

Main Methods:

• Synthesis of a Rh-Beta catalyst with atomically dispersed Rh species in a BEA zeolite matrix.
• Methane oxidation reactions in a CH4-O2-CO-H2O system.
• Mechanistic studies using spectroscopy and theoretical calculations.

Main Results:

• Achieved a formic acid space-time yield of 210 mol molRh-1 h-1 at 7.84% methane conversion.
• Attained 96% formic acid selectivity, surpassing previous catalyst systems.
• Identified hydroxyl radicals as key intermediates for methane activation.

Conclusions:

• The Rh-Beta catalyst demonstrates exceptional performance for selective methane oxidation.
• Zeolite matrix stabilizes intermediates and promotes formic acid formation.
• This work provides a viable route for selective methane functionalization under mild conditions.