C-Dot TiO2 nanorod composite for enhanced quantum efficiency under direct sunlight

Abstract

C-Dots obtained from a sustainable route (melon-rinds were used as the source) were combined with TiNRs to create a composite via a simple hydrothermal technique. The obtained materials were subjected to analyses viz. FESEM, XRD, Raman spectroscopy, XPS, PL, FTIR and UV-vis-DRS for understanding their intrinsic nature. The solar photocatalytic performance was evaluated by the degradation of methyl orange (MO) as a model pollutant. The optical properties indicated that there was a clear redshift in the composite with a band gap of 2.49 eV, while the XRD results corresponded to a calculated crystalline size of 24.80 nm. The PL analysis proved the role of C-dots as an electron surge to the TiNRs. The photocatalytic reaction was faster with C-dots as compared to the solo TiNR with a higher degradation of 93.3% within 150 min obeying pseudo-first order kinetics with a rate constant k = 0.01723 min⁻¹. The charge carrier scavenging investigation showed the role of numerous reactive oxygen species (ROS) on the degradation of MO. The formulated composite has demonstrated its ability in effectively handling the contaminants in water. Thus, this study establishes the two-step thermal method as an easy, facile, environmentally-friendly, and low-cost synthesis method for the large-scale production of a photocatalyst.