A comparison study of the graphitic carbon nitride Coupled TiO2 prepared by using titania precursor and Degussa P25 TiO2 under photocatalytic degradation of methylene blue and reactive red 4 dyes / Zawani Ab Wahab

In this study, two different preparations of graphitic carbon nitride / titanium dioxide (g-C3N4/TiO2) photocatalysts were prepared by using two different titania precursors (tetrabutyl ortotitanate (TBOT) and Degussa P25) with 1, 2, and 5 wt% of graphitic carbon nitride using in situ sol gel hydrothermal method. The photocatalytic activity of prepared samples was measured under methylene blue (MB) and reactive red 4 (RR4) dyes using 55-Watt fluorescent lamp. 2 wt.% g-C3N4 incorporated with TiO2 using TBOT as precursor (2% g-C3N4/TiO2) gave the highest photocatalytic degradation rates among the other photocatalysts under MB and RR4 dyes at 0.0321 and 0.0651 cm-1, respectively. While, 2 wt.% g-C3N4 incorporated with TiO2 using P25 as precursor (2% g-C3N4/P25) gave the highest photocatalytic degradation rates among the other photocatalysts under MB and RR4 dyes at 0.0337 and 0.0553 cm-1 respectively. This study shows that two different optimum k values were observed under two types of sample’s precursors. The g-C3N4/TiO2 gave high k value in RR4 dye while g-C3N4/P25 give high k value in MB dye. The different photocatalytic performance is due to the differential point of zero charge (pzc) analysis were ca. 4.6 and 6.2 for 2% g-C3N4/TiO2 and 2%g-C3N4/P25, respectively. The FTIR and XRD analyses showed that the samples exhibit all the peaks for g-C3N4 and TiO2 which indicates the presence both compounds in the prepared samples. The morphology of the prepared samples was elucidated via FESEM shows the graphitic carbon nitride successfully dispersed on the TiO2. It shows that the 2% composite of g-C3N4/TiO2 has smallest particle size and also largest specific surface are which can leads to the increasing of dispersion and diffusion of electron between photocatalyst and dyes.