Deep Photocatalytic Oxidation of Aromatic VOCs on ZnSn LDH: Promoting Role of Electron Enrichment of Surface Hydroxyl

Abstract

Photocatalytic oxidation is a very promising technology for air purification, but its wide application is greatly limited by poor mineralization capacity and catalytic stability. Herein, we successfully tailored and identified the deep oxidation of aromatic VOCs including toluene, styrene, and chlorobenzene by electron enrichment of surface hydroxyl (OH) over ZnSn LDH photocatalyst. By means of regulation of electron donation of Sn atom to OH, the electron density of OH is effectively increased. The electron-rich OH greatly enhanced the interaction between the aromatic VOCs and the photocatalyst, concurrently promoting the reactive oxygen species formation including •OH and •O2–, which allowed rapid opening of the aromatic ring and deep oxidizing into CO2. 100% of toluene removal and mineralization efficiency was attained on ZnSn LDH at a high weight hourly space velocity (WHSV) of 60 000 mL gcat–1 h–1. Moreover, ZnSn LDH exhibited impressive adaptability for varying humidity and concentration, as well as satisfactory durability for long-term reaction. This work provides a simple and effective strategy for regulating the electron density of surface hydroxyls, and it provides an approach for purifying refractory pollutants.