Fabrication of TiO2/NiO p-n Nanocomposite for Enhancement Dye Photodegradation under Solar Radiation

Abstract

A p-n nanocomposite based on TiO2 nanotubes (NTs) and NiO nanoparticles (NPs) was designed and optimized in this study to improve the photocatalytic performance of methylene blue (MB). The hydrothermal technique has been used to produce TiO2/NiO nanocomposites with different NiO NPs weight ratios; 1TiO2:1NiO, 1TiO2:2NiO, and 1TiO2:3NiO. The crystal phase, chemical composition, optical properties, and morphology of TiO2/NiO were explored by various techniques. TiO2 NTs have a monoclinic structure, while NiO NPs have a cubic structure, according to the structural study. The bandgap of TiO2 NTs was reduced from 3.54 eV to 2.69 eV after controlling the NiO NPs weight ratio. The TiO2/2NiO nanocomposite showed the best photodegradation efficiency. Within 45 min of solar light irradiation, the efficiency of MB dye degradation using TiO2/2NiO hits 99.5% versus 73% using pure TiO2 NTs. Furthermore, the catalytic photodegradation efficiency did not deteriorate significantly even after five reusability cycles, intimating the high stability of the TiO2/2NiO nanocomposite. This suggests that the loading of NiO NPs into TiO2 NTs lowers the recombination of photo-produced electron/hole pairs and enlarged solar spectral response range, which results in improved photocatalytic activity. The mechanism of charge transfer in the TiO2/NiO and kinetic models were discussed for the photodegradation of MB.

Green Synthesis of CS-TiO2 NPs for Efficient Photocatalytic Degradation of Methylene Blue Dye

“…Our design showed higher photocatalytic degradation% within a short time relative to the reported data in references [36,41,43,44,46]. Additionally, using a lower catalyst dose than that reported in references [35,[37][38][39][40]42,45], showed high catalytic efficiency.…”

“…This figure provided error bars of triplicate measurements. Table 2 shows the performance of our designed photocatalyst relative to the previously reported TiO 2 -based photocatalysts [35][36][37][38][39][40][41][42][43][44][45][46]. Our design showed higher photocatalytic degradation% within a short time relative to the reported data in references [36,41,43,44,46].…”

“…Figure 6c shows the plots of the pseudo-first-order degradation kinetics at 5 mg and 10 mg catalyst doses [36][37][38][39]. This figure reveals linear relationships with correlation coefficients > 0.99 as shown in Table 1, showing that the photocatalytic reaction has pseudo-first-order degradation kinetics.…”

“…Cannabis sativa (bhang)-mediated CS-TiO2 absorbs an appropriate frequency of irradiation. The electron is stimulated to the conduction band and a positive charge (hole) is produced in the lower band of CS-TiO2 [39]:…”

“…The photocatalytic performance of CS-TiO 2 NPs relative to previously reported TiO 2 -based photocatalysts[35][36][37][38][39][40][41][42][43][44][45][46].…”