Accelerating the Low-Temperature Catalytic Oxidation of Acetone over Al-Substituted Mn-Al Oxides by Rate-Limiting...

Area of Science:

• Materials Science
• Catalysis
• Environmental Chemistry

Background:

• Manganese-aluminum (Mn-Al) oxides are explored for catalytic applications.
• Acetone oxidation is a key process for volatile organic compound (VOC) degradation.
• Improving catalyst activity and stability is crucial for efficient industrial processes.

Purpose of the Study:

• To investigate the effect of Al substitution on Mn-Al oxides for acetone oxidation.
• To understand how Al substitution modulates the catalytic mechanism and rate-limiting step.
• To develop highly active and stable catalysts for VOC mineralization.

Main Methods:

• Preparation of Mn-Al oxides using a hydrothermal-redox strategy.
• Catalytic testing of Mn-Al oxides for acetone oxidation.
• Analysis of reaction kinetics, selectivity, and stability.
• Density Functional Theory (DFT) calculations to elucidate reaction mechanisms.

Main Results:

• Al substitution in Mn-Al oxides significantly enhances catalytic activity and stability for acetone oxidation.
• The optimal catalyst, MnAl0.5, achieved 90% acetone conversion at 165 °C with high CO2 yield.
• Al substitution shifted the rate-limiting step from acetic acid dissociation to ethanol decomposition, accelerated by water molecules.
• DFT studies revealed the crucial role of Mn d-orbitals and Al p-electrons in the rate-limiting step.

Conclusions:

• Modulating the rate-limiting step via Al substitution is key for efficient catalytic destruction of hydrocarbons.
• Al-substituted Mn-Al oxides represent promising catalysts for industrial VOC abatement.
• This study offers insights into designing advanced catalysts for economical and efficient mineralization of VOCs.