Effective photoreduction of graphene oxide for photodegradation of volatile organic compounds

Xin Hong Tai; Soon Wei Chook; Chin Wei Lai; Kian Mun Lee; Thomas Chung Kuang Yang; Siewhui Chong; Joon Ching Juan

doi:10.1039/c9ra01209e

Effective photoreduction of graphene oxide for photodegradation of volatile organic compounds

RSC Adv. 2019 Jun 10;9(31):18076-18086. doi: 10.1039/c9ra01209e. eCollection 2019 Jun 4.

Authors

Xin Hong Tai¹, Soon Wei Chook¹, Chin Wei Lai¹, Kian Mun Lee¹, Thomas Chung Kuang Yang², Siewhui Chong³, Joon Ching Juan^{1

4}

Affiliations

¹ Nanotechnology & Catalysis Research Centre (NANOCAT), Institute for Advanced Studies (IAS), University of Malaya Kuala Lumpur Malaysia jcjuan@um.edu.my.
² Department of Chemical Engineering and Biotechnology, National Taipei University of Technology Taipei Taiwan.
³ Department of Chemical and Environmental Engineering, Faculty of Science and Engineering, University of Nottingham Malaysia Jalan Broga 43500 Selangor Malaysia.
⁴ School of Science, Monash University, Malaysia Campus Jalan Lagoon Selatan, 46150, Sunway Selangor Malaysia.

Abstract

Nowadays, humans spend most of their time indoors and are frequently exposed to volatile organic compounds (VOCs) from various sources. The photocatalytic oxidation (PCO) method is a relatively more efficient method than the adsorption method for removing VOCs from the environment. In this work, graphene oxide (GO) was partially reduced via photoreduction under ultraviolet light (UV-A) irradiation and then used as a photocatalyst to degrade VOCs. After photoreduction, the band gap of the partially reduced graphene oxide (PRGO) decreased from 3.5-4.5 eV to 3.1-4.0 eV. Methanol vapour, which acts as a model VOC, was photodegraded using the PRGO. The effectiveness of the PRGO was mainly due to the removal of oxygen functional groups and restoration of the sp² domain. This lowered the band gap and slowed down the electron recombination rate, which resulted in a higher photocatalytic activity. The photocatalytic activity of PRGO followed pseudo-first order kinetics, with a rate constant of 0.0025 min^-1, and it could be reused for five cycles without any significant loss in the photocatalytic activity. This study demonstrates the potential of PRGO as a versatile and stable metal-free photocatalyst to remove indoor pollutants.