Green Synthesis of ZnO-GO Composites for the Photocatalytic Degradation of Methylene Blue

Abstract

Beneficial from the excellent optical performance of zinc oxide (ZnO) nanocrystals and the absorption properties of graphene oxide (GO), the nanocomposites of ZnO and GO with synergistic photocatalytic effects were prepared by a precipitation method, in which GO is utilized as the catalyst carrier. The prepared composites were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, UV-vis spectroscopy, field emission scanning electron microscopy, and transmission electron microscopy and also performed photocatalytic activity for the nanocomposites. The results show that ZnO is uniformly loaded on the surface of GO assisted by an effective interface coupling. Due to interface coupling between ZnO and GO, electrons can be directly transferred from the valence band of ZnO to GO. The photodegradation efficiency of the composites reaches to 97.6%, and the first-order reaction rate constant of photodegradation is calculated to be 0.04401 min-1. The novel ZnO-GO composites with excellent photocatalytic performance display promising potential applications in the field of photocatalysis and will provide a new platform for building next-generation graphene-based semiconductor composites.

<i>Malus domestica</i> and <i>Solanum lycopersicum</i> Mixtures for the Synthesis of Graphene Silver and Zinc Oxide Nanocomposites

“…Therefore, from the Raman spectra, it is observed that there is the attachment of ZnONPs or AgNPs onto the GO matrix leading to partial restoration of the sp 2 network. Both these results are consistent with previous reports on the Raman spectra of AgNPs|GO and of ZnONPs|GO [34] [35] [36].…”

“…and GO through the modification of the fundamental process of electron-hole pair formation. Although these findings are very similar to those reported by Lin et al, 2020 [34]; the two extracts used in this study caused lower wavelength readings as opposed to their study where a precipitation method was used to synthesize ZnONPs|GO. This is also noteworthy due to the small nature of the nanoparticles produced in this study.…”

Enhanced photocatalytic activity and diode performance of ZnO‐GO nanocomposites via doping with aluminum

“…As shown in the inset of Figure 9A, the presence of a peak at around 271 nm reflects the n-π* transitions of C=O bonds (π-plasmon) of graphene oxide verifying the existence of GO. 37 Also, The absorbance refers to a strong peak that appeared at 376 nm, which is attributed to the O 2p -Zn 3d transition of ZnO, 76 the fundamental transition in ZnO from the valence band to the conduction band. It easily can be noticed a slight red-shift in the absorption edge of ZnO when alloying with Al that reflects the variation of the band gap.…”

“…The GO is a superior electron collector together with excellent transporter and thus minimizes the recombination of electron‐hole pairs generated from ZnO. Based on these exciting properties, numerous attempts have been interested in investigating the ZnO/GO nanocomposites 37,38 . However, by far, we have a lack of basic and applied information on the impact of Al on the ZnO‐GO nanocomposites.…”

“…Based on these exciting properties, numerous attempts have been interested in investigating the ZnO/GO nanocomposites. 37,38 However, by far, we have a lack of basic and applied information on the impact of Al on the ZnO-GO nanocomposites. In this work, the low doping of Al was selected because many previous works, 39,40 have reported that low concentration of Al decreased the band gap, while heavily doping increased the band gap.…”