Enhanced Replenishment of Active Lattice Oxygen Using Chiral Copper Oxide

Area of Science:

• Materials Science
• Catalysis
• Surface Chemistry

Background:

• Transition metal oxides are effective catalysts due to surface area, oxygen atoms, and valence ratios.
• Chirality in transition metals is mainly studied for optical applications, with limited exploration in thermal catalysis.
• The influence of chiral catalysts on gas-solid thermal catalysis remains underexplored.

Purpose of the Study:

• To investigate the effect of chirality in copper oxide (CuO) catalysts on the thermal catalytic oxidation of toluene.
• To compare the performance of chiral (l-CuO, d-CuO) and achiral CuO catalysts loaded with manganese (Mn).
• To elucidate the structure-activity relationship between catalyst chirality and catalytic efficiency.

Main Methods:

• Synthesis of Mn-loaded chiral (M/l-CuO, M/d-CuO) and achiral (M/a-CuO) catalysts.
• Characterization of catalyst structure, including chirality and Mn dispersion.
• Evaluation of catalytic performance in toluene oxidation at 240 °C, measuring toluene turnover frequency (TOF).

Main Results:

• Mn was well-dispersed on both chiral and achiral CuO supports.
• Chiral CuO exhibited nanoflower-like structures with chirality originating from (001) plane angles.
• Mn/d-CuO showed the highest TOF (5.6 × 10⁻⁵ s⁻¹), followed by Mn/l-CuO (4.4 × 10⁻⁵ s⁻¹), and Mn/a-CuO (3.2 × 10⁻⁵ s⁻¹).
• Catalyst performance correlated with oxygen replenishment rate, with chiral catalysts showing faster rates.
• Similar ratios of oxygen species and metal valence states were observed across catalysts.

Conclusions:

• Catalyst chirality significantly influences gas-solid thermal catalysis, specifically in toluene oxidation.
• Chirality enhances catalytic activity by accelerating the lattice oxygen replenishment speed.
• This study highlights the potential of chiral transition metal oxides as efficient catalysts in structure-activity driven gas-solid reactions.