Visible light antibacterial potential of graphene-TiO₂ cementitious composites for self-sterilization surface

Abstract

Graphene oxide-titanium dioxide (GO-TiO₂) composite was synthesized with one step hydrothermal process. The structure and morphology were characterized by field-emission-scanning-electron-microscopy, Thermogravimetric analysis, X-ray diffraction, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Photocatalytic activity against Escherichia coli inactivation was carried out by GO-TiO₂ mixed with cement composite under visible light. The result revealed no significant difference between morphology of GO-TiO₂ and pristine TiO₂. FESEM and FTIR results showed the presence of carbon component in the GO-TiO₂ composites. TGA-IR confirmed that the GO content (3%) in the composite could be controlled during the synthesis process. The synthesized GO-TiO₂ had stronger visible light absorption and narrower bandgap (3.11 eV) than TiO₂ (3.21 eV). The bandgap reduction was also observed in cement sample with GO-TiO₂ (3.08 eV) which could be beneficial for reducing the energy needed for photoexcitation. As a result, the specimen with GO-P25 outperformed specimens with others for Escherichia coli inactivation.

Keywords:

• antibacterial
• cementitious composites
• titanium dioxide
• graphene oxide
• Escherichia coli inactivation

Author contributions

Conceptualization, A.H.H. and S.Q.; Methodology, A.H.H and Y.D; Validation, A.H.H and Y.D.; Formal Analysis, A.H.H; Investigation, A.H.H and Y.D.; Resources, A.H.H., Y.D. and S.Q.; Data Curation, A.H.H and Y.D.; Writing – Original Draft Preparation, A.H.H; Writing – Review & Editing, Y.D. and S.Q.; Visualization, A.H.H; Supervision, S.Q.; Project Administration, A.H.H. and S.Q.; Funding Acquisition, S.Q.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This study was supported by the Academic Research Fund (AcRF) Tier 1 from Ministry of Education, Singapore [Grant No. RG87/15] and the NTU Research Scholarship to the first author.