One Pot Synthesis of Pineapple Juice Derived - Carbon Quantum Dots and TiO2 Composite for Solar Light Active Photocatalysis

CDs/TiO2 composites were prepared using pineapple juice as a green precursor through one pot hydrothermal method. The obtained CDs exhibited green-blue fluorescence under UV radiation and abundant of surface functional groups. The absorption spectra of CDs/TiO2-200 and CDs/TiO2-120 was red shifted towards visible and NIR region after loading with CDs. Pure anatase and graphite phase were detected in CDs/TiO2. Insignificant emission peak was observed when CDs were excited with wavelength above 540 nm which demonstrated the absence of upconversion photoluminescence (UCPL) properties in CDs. Both of CDs/TiO2-200 and CDs/TiO2-120 fully degraded BPA solution in 150 and 180 mins, respectively. The photocatalytic performance of both CDs/TiO2-200 and CDs/TiO2-120 were 2.5 times of that using P25 under solar irradiation. The presence of CDs in TiO2 composite effectively suppressed the charge recombination and enhanced visible and NIR light absorption. Keywords: carbon quantum dots, TiO2, solar light, Bisphenol A, pineapple, green precursor.