Structure, wettability and photocatalytic activity of graphene doped multi-walled carbon nanotubes/titanium dioxide hybrid coatings

This paper presents the findings of the structure, wettability and photocatalytic activity of 32 wt % graphene-doped multi-walled carbon nanotubes (G-MWCNTs) / titanium dioxide (TiO2) hybrid coatings under three different ratios. The hybrid coatings of G-MWCNTs/TiO2 were compared with the pure (undoped) TiO2 coating. Pure TiO2 and G-MWCNTs/TiO2 hybrid coatings were prepared by sol-gel method and deposited on soda-lime-silica (SLS) glass substrates using a dip coater. The samples were heat-treated in the air at 500 °C for 1 h. The nano-sized G and MWCNTs used as dopants in the resulting hybrid solution were mixed without agglomeration by the sonication method based on the DLVO theory, without any surfactants. To prevent the migration of Na+ ions contained in the structure of SLS glass to TiO2-based coatings, a SiO2-based sol-gel coating was first deposited on the SLS glass surface using the dip coating method. This was done before applying the pure TiO2 coating and G-MWCNTs/TiO2 hybrid coating process. All samples were crystallized in the anatase form and exhibited superhydrophilic behavior. The G-MWCNTs/TiO2 hybrid coated samples' photoactivity was determined using the ISO 10678 MB degradation standard. According to the ISO 10678:2010 MB degradation standard, G-MWCNTs/TiO2 hybrid coated samples exhibited photonic efficiency.