Comparison of Ga2O3 and TiO2 Nanostructures for Photocatalytic Degradation of Volatile Organic Compounds

Tae Hee Yoo,Byung Jin Cho,In Gyu Lee,Junsang Cho,Wan Sik Hwang,Heejoong Ryou

doi:10.3390/catal10050545

Abstract

The photocatalytic degradation of formaldehyde, acetaldehyde, toluene, and styrene are compared using monoclinic Ga2O3 and anatase TiO2 nanostructures under ultraviolet-C irradiation. These Ga2O3 and TiO2 photocatalysts are characterized using a field emission scanning electron microscope, a powder X-ray diffraction system, the Brunauer–Emmett–Teller method, and a Fourier transform infrared spectrometer. The Ga2O3 shows a higher reaction rate constant (k, min−1) than TiO2 by a factor of 7.1 for toluene, 8.1 for styrene, 3.1 for formaldehyde, and 2.0 for acetaldehyde. The results demonstrate that the photocatalytic activity ratio of the Ga2O3 over the TiO2 becomes more prominent toward the aromatic compounds compared with the nonaromatic compounds. Highly energetic photo-generated carriers on the conduction/valence band-edge of the Ga2O3, in comparison with that of the TiO2, result in superior photocatalytic activity, in particular on aromatic volatile organic compounds (VOCs) with a high bond dissociation energy.

Highlights

Indoor air quality has become an urgent issue as most people spend large amounts of time in residential and commercial buildings [1]
One of the main concerns indoors is the volatile organic compounds (VOCs) that are emitted from a wide range of chemicals and consumer products during use and even in storage
Photocatalytic oxidation (PCO) is a promising method to remove low-level VOCs compared with absorption and incineration methods because it is effective, inexpensive, and eco-friendly [2]

Summary

Introduction

Indoor air quality has become an urgent issue as most people spend large amounts of time in residential and commercial buildings (such as housing complexes, schools, and offices) [1]. One of the main concerns indoors is the volatile organic compounds (VOCs) that are emitted from a wide range of chemicals and consumer products during use and even in storage. These VOCs are harmful to health and can cause respiratory symptoms, allergic skin reactions, headaches, and even cancer under long-term exposure. Semiconductor nano/microstructures can be used as efficient photocatalytic platforms wherein charge carriers (electron and hole pairs) are generated upon light irradiation with above-bandgap excitation [3,4]

Methods

Results

Conclusion