Jump to main content
Jump to site search

Issue 46, 2016
Previous Article Next Article

A highly efficient g-C3N4/SiO2 heterojunction: the role of SiO2 in the enhancement of visible light photocatalytic activity

Author affiliations

Abstract

SiO2, an insulator, hardly has any photocatalytic acitivity due to its intrinsic property, and it is generally used as a hard template to increase the surface area of catalysts. However, in this work, we found that the surface state of the insulator SiO2 can promote the migration of photogenerated charge carriers, leading to the enhancement of the photooxidation ability of graphitic carbon nitride (g-C3N4). A one-pot calcination method was employed to prepare g-C3N4/SiO2 composites using melamine and SiO2 as precursors. The composites present considerably high photocatalytic degradation activities for 2,4-dichlorophenol (2,4-DCP) and rhodamine B (RhB) under visible light (λ > 420 nm) irradiation, which are about 1.53 and 4.18 times as high as those of bulk g-C3N4, respectively. The enhancement of the photocatalytic activity is due to the fact that the introduction of the insulator SiO2 in g-C3N4/SiO2 composites can greatly improve the specific surface area of the composites; more importantly, the impurity energy level of SiO2 can help accelerate the separation and transfer of electron–hole pairs of g-C3N4. Electron paramagnetic resonance (EPR) spectroscopy and trapping experiments with different radical scavengers show that the main active species of g-C3N4 are superoxide radicals, while holes also play a role in photodegradation. For g-C3N4/SiO2-5, besides superoxide radicals and holes, the effect of hydroxyl radicals was greatly improved. Finally, a possible mechanism for the photogenerated charge carrier migration of the g-C3N4/SiO2 photocatalyst was proposed.

Graphical abstract: A highly efficient g-C3N4/SiO2 heterojunction: the role of SiO2 in the enhancement of visible light photocatalytic activity

Back to tab navigation
Please wait while Download options loads

Supplementary files

Publication details

The article was received on 05 Sep 2016, accepted on 28 Sep 2016 and first published on 30 Sep 2016


Article type: Paper
DOI: 10.1039/C6CP06122B
Citation: Phys. Chem. Chem. Phys., 2016,18, 31410-31418
  •   Request permissions

    A highly efficient g-C3N4/SiO2 heterojunction: the role of SiO2 in the enhancement of visible light photocatalytic activity

    Q. Hao, X. Niu, C. Nie, S. Hao, W. Zou, J. Ge, D. Chen and W. Yao, Phys. Chem. Chem. Phys., 2016, 18, 31410
    DOI: 10.1039/C6CP06122B

Search articles by author