Enhancement of gaseous toluene removal by photocatalysis using hydrothermal synthesis carbon nanodots/TiO2 combined with zeolite ZSM-5

Abstract

Many studies have been conducted to produce composite materials that possess the ability to transform volatile organic compounds (VOCs) to other nontoxic forms economically and environmentally by means of photocatalytic method. However, the main drawbacks of these materials include restricted surface area, low affinity towards organic molecules, and wide band gap energy which dramatically inhibit their performance. In this research, a composite material that surpasses the above disadvantages has been successfully synthesized from TiO2 - carbon nanodots (CDs) - zeolite ZSM-5. Particularly, CDs synthesized by bottom-up method were coated on TiO2 before being uniformly distributed on zeolite ZSM-5. The powder samples with varying CDs/TiO2 and zeolite ZSM-5 content were tested for their photocatalytic oxidization capability to determine the appropriate ratio. The results revealed that samples with higher zeolite content improved photocatalytic activity. Under other survey conditions such as low toluene flowrate, high relative humidity as well as high UV intensity, the photocatalytic performance was enhanced notably. The newly produced material has corrected most disadvantages of traditional photocatalysts, however, further researches need to be made to improve the removal stability.