High Photocatalytic Effect of Graphene Oxide/Halloysite Nanotubes/Zinc Oxide Nanocomposites for Degradation of Organic Dyes

Abstract

Halloysite nanotubes (HNTs) are nature-generated clay materials with nanotube structures. They have a large outer diameter of the Si-O group on the outside and the Ai-O group on the inside. HNTs is used in various applications with 10 Å interlayer spaces and high absorption. HNTs is used as a supporting effect for polymer coating, enhanced dye adsorption, antibacterial effect, filter and so on. Graphene oxide (GO) is a sp2 bond and a light conductive material. As a result, it has a good adsorption component and is used for membranes and inks. In this study, we used the synergistic adsorption of HNTs and GO as the motivation. Photocatalytic experiments were conducted based on the use of the two as catalysts. ZnO was used as a photocatalysis and Methyl Orange (MO) and Rhodamine B (RB) were used as organic dyes. ZnO of a semiconductor material has a band gap of 3.17 eV. It is actively used as a photocatalysis. However, raw ZnO nanoparticles are poorly active in large amounts and for long time photocatalysis due to its strong aggregation. We combined adsorptive HNTs and GO with ZnO to create new super nanocomposite of GO/HNTs/ZnO. To characterize nanocomposites, we used Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDX), Ultraviolet Visible Spectroscopy (UV), Fourier Transform Infrared Spectroscopy (FTIR), Raman Spectroscopy, High Resolution X-ray Diffraction (XRD), Zeta Potential and Dynamic Light Scattering (DLS) instruments. The photocatalytic activity of GO/HNTs/ZnO is the best nanocomposite to degradation methyl orange. However, in a short time, high photocatalytic effect was the target. The experimental factors were adjusted to find super photocatalytic degradation of conditions. In addition, experiments were carried out to convert raw HNTs into purified HNTs (PHNTs) to increase the efficiency of the photocatalysis. For photocatalytic activity, rhodamine b exposed to UV light for 60 min by GO/PHNTs/ZnO was resulted in high photocatalytic degradation effect.