2D reduced graphene oxide–titania nanocomposites synthesized under different hydrothermal conditions for treatment of hazardous organic pollutants--颗粒学报PARTICUOLOGY

Kim, M., Hong, W.-H., Kim, W., Park, S. H., & Jo, W.-K. (2018). 2D reduced graphene oxide–titania nanocomposites synthesized under different hydrothermal conditions for treatment of hazardous organic pollutants. Particuology, 36, 165-173. https://doi.org/10.1016/j.partic.2017.05.005

2D reduced graphene oxide–titania nanocomposites synthesized under different hydrothermal conditions for treatment of hazardous organic pollutants

Migyeong Kim ^a, Won-Hwa Hong ^b, Woong Kim ^a, Sung Hyuk Park ^c, Wan-Kuen Jo ^a *

a Department of Environmental Engineering, Kyungpook National University, Daegu 702-701, Republic of Korea
b School of Architecture, Kyungpook National University, Daegu 702-701, Republic of Korea
c Department of Materials Science and Metallurgical Engineering, Kyungpook National University, Daegu 702-701, Republic of Korea

10.1016/j.partic.2017.05.005

Volume 36, February 2018, Pages 165-173

Received 28 March 2017, Revised 4 May 2017, Accepted 6 May 2017, Available online 7 August 2017, Version of Record 22 December 2017.

E-mail: wkjo@knu.ac.kr

Highlights

• Graphene–TiO₂ composites were prepared using various hydrothermal conditions.

• The synthesized composites showed higher activity with daylight exposure.

• An optimal hydrothermal reaction time for the synthesis of composites existed.

• Violet LEDs were energy-efficient for degradation of gas pollutants over composites.

• Mass transfer, rather than surface reaction, could limit photocatalytic reaction rate.

Abstract

Two-dimensional reduced graphene oxide–titania (RGO–TiO₂) composites were prepared using a single-step hydrothermal method under various hydrothermal reaction conditions. The morphological and surface characteristics of the RGO–TiO₂ composites and reference materials were determined. The RGO–TiO₂ composites showed photocatalytic activity for the decomposition of two target pollutants that was superior to both pure TiO₂ and RGO under fluorescent daylight lamp illumination. The photocatalytic activity of the RGO–TiO₂ composite increased as the hydrothermal treatment time increased from 1 to 24 h, but then it decreased as the time increased to 36 h, which indicated the presence of an optimal treatment time. RGO–TiO₂ composites activated by violet light-emitting diodes (LEDs) displayed lower decomposition efficiency than those activated by a daylight lamp, likely because of the lower light intensity of violet LEDs (0.2 mW/cm²) when compared with that of the daylight lamp (1.4 mW/cm²). However, the photocatalytic decomposition of the target pollutants using the RGO–TiO₂ composite was more energy-efficient using the violet LEDs. The photocatalytic reaction rates increased as the residence time decreased, whereas the reverse was true for the decomposition efficiency.

Graphical abstract

Keywords

TiO₂ composite; Continuous-flow mode; Hydrothermal time; Violet; Light emitting diode

文章导读