SnTCPP-modified ZnO nanorods prepared via a simple co-precipitation method: application as a new photocatalyst for photodegradation and photoreduction processes

Abstract

In this paper, ZnO nanorods were synthesized after optimizing the parameters of pH and the concentration of raw materials, reflux temperature, reflux time and annealing temperature through the co-precipitation method. The resulting nanorods with 90 nm average diameters have a wurtzite hexagonal crystalline structure. To improve the photocatalytic efficiency of the prepared photocatalyst in the visible light region, ZnO nanorods were functionalized with a tin porphyrin (SnTCPP) photosensitizer. The prepared photocatalysts were characterized through FT-IR, DRS, XRD and SEM analysis. The photoactivity of the prepared samples was investigated via photodegradation of a colored pollutant of methyl orange and photoreduction of graphene oxide. The results showed that ZnO photosensitized with SnTCPP is able to destroy 85 % of methyl orange in 240 min under visible light radiation. The investigation of the photocatalytic mechanism determined that $${\text{O}}_{2}^{ - }$$ is the major species in the photodegradation of methyl orange over the SnTCPP/ZnO compound. In addition, the photoreduction process was suitably carried out using SnTCPP/ZnO compound. The reduced graphene oxide was obtained during 2 h of the photoreduction process over the prepared SnTCPP/ZnO compound. Thus, porphyrin photosensitizer can be very helpful in activating the ZnO photocatalyst in the visible region.