Bi/SnO2/TiO2-graphene nanocomposite photocatalyst for solar visible light-induced photodegradation of pentachlorophenol

In this study, for the first time, a TiO2/graphene (G) heterostructure was synthesized and doped by Bi and SnO2 nanoparticles through a hydrothermal treatment. The as-synthesized nanocomposite was employed for photocatalytic degradation of pentachlorophenol (PCP) under visible light irradiation. Structural characterizations such as X-ray photoelectron spectroscopy (XPS) and X-ray diffraction spectroscopy (XRD) proved the valence band alignment at Bi/SnO2/TiO2-G interfaces and crystallinity of the nanocomposite, respectively. The as-developed nanocomposite photocatalyst was able to decompose 84% PCP, thanks to the generation of a large number of active OH center dot- and O-2(center dot-) radicals. To achieve this optimum photodegradation efficiency, various parameters such as pH, catalyst dosage, and PCP concentration were optimized. The results showed that the PCP photodegradation process followed the first-order kinetic model and the reaction rate constant rose from 0.007 min(-1) (Bi) to 0.0149 min(-1) (Bi/SnO2/TiO2-G). The PCP photodegradation efficiency did not decrease significantly after 5 cycles, and the nanocomposite photocatalyst still showed a high efficiency of 68% in the last cycle. The excellent photocatalytic activity of Bi/SnO2/TiO2-G is ascribed as well as the heterostructure of the nanocomposite photocatalyst.

Automated summary

A TiO2/graphene (G) heterostructure doped with Bi and SnO2 nanoparticles was synthesized and used for photocatalytic degradation of pentachlorophenol (PCP) under visible light irradiation. The nanocomposite showed promising photodegradation efficiency due to the generation of active radicals. Optimizing parameters such as pH, catalyst dosage, and PCP concentration improved the photocatalytic activity.