Photocatalytic Activation of Dealuminated Zeolite through In Situ Formation of Defective Graphene.

Abstract

Adsorbents such as zeolite are widely used for volatile organic compounds (VOCs) removal, but a practical challenge is the decrease in VOCs removal efficiency under humid environment by competitive adsorption between water vapor and VOCs, which requires frequent regeneration using external energy. A combination of zeolites with photocatalytic materials can address this issue by oxidizing adsorbed VOCs from the zeolite surface to CO₂ gas under light irradiation. Herein, the in situ formation of photocatalytic active defect-rich graphene is presented on a commercial zeolite surface (ZSM-5) when properly dealuminated ZSM-5 is exposed to an acetaldehyde/humid air mixture under visible light. This in situ photocatalytic activation occurs when a critical amount of local surface coverage of acetaldehyde and water molecules is achieved on a dealuminated zeolite surface under visible light. The findings not only provide a deeper understanding of VOCs removal by zeolite but also suggest a new and simple approach to enhancing the performance of zeolite for VOCs removal through the combination with a photocatalytic material.