Continuous near-complete photocatalytic degradation of toluene by V/N-doped TiO2 loaded on honeycomb ceramics under UV irradiation

Abstract

Photocatalytic degradation of volatile organic compounds (VOCs) is a significant applying aspect of photocatalysis. Both the modulation of photocatalysts and the rational dispersion of them on supports are key for solar-driven VOC degradation. Conventional batch-type photoreactors have low efficiency while continuous-flow photoreactors suffer from the problem of incomplete removal of VOCs. Herein, aiming for continuous and complete degradation of toluene gas as the target contaminant, continuous-flow photocatalytic degradation reactors were made by adhering the vanadium and nitrogen codoped TiO2 on honeycomb ceramics (V/N-TiO2@HC) by a simple sol-gel method. In such a reactor, the rich ordered pores in the HC accelerate mass transport of toluene, and the introduction of V/N dopants narrows the bandgap and widens the light absorption range of TiO2, together resulting in continuous and nearly-complete photocatalytic degradation of toluene. The unique and stable structure of HC allows the photocatalysts to be reused. The degradation rate of toluene gas can reach 97.8%, and after 24 rounds of photocatalytic degradation, there is still a degradation rate of 96.7%. The impacts of loading times and gaseous flow rate on the photocatalytic performance of V/N-TiO2@HC are studied in detail. Our study provides a practical solution for the continuous and complete photocatalytic degradation of VOCs and opens a new application field for HC.