Green hybrid photocatalyst containing cellulose and γ–Fe2O3–ZrO2 heterojunction for improved visible-light driven degradation of Congo red

Abstract

In the present study, we aimed to investigate the photocatalytic behavior of a novel bimetal-biopolymer nanocomposite of cellulose/γ–Fe2O3–ZrO2 that was efficiently synthesized using a simple sol-gel method for photocatalytic applications. The photocatalysts were characterized by UV–visible diffuse reflectance spectrophotometry (DRS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Brunauer‒Emmett‒Teller (BET); the optical properties were determined by UV–visible spectrophotometry. Nano-ZrO2 significantly decreased the optical bandgap of nano-γ–Fe2O3 from 4.90 eV to 2.28 eV at the γ–Fe2O3:ZrO2 ratio of 1:1. Although the effect of nanocellulose on the energy bandgap of γ–Fe2O3–ZrO2 heterojunctions was insignificant, the impact of nanocellulose on the photocatalytic degradation of Congo red increased from 80.0% to 98.5% in 30 min, and the maximum degradation value was obtained at the nanocellulose:Fe2O3–ZrO2 ratio of 1:1. These results showed that the cellulose/γ–Fe2O3–ZrO2 nanocomposite demonstrated a higher photodegradation efficiency of Congo red under visible light than γ–Fe2O3–ZrO2, nano-γ–Fe2O3, and nano-ZrO2. Briefly, our results confirm that the cellulose/γ–Fe2O3–ZrO2 nanocomposite shows good photocatalytic activity toward the degradation of Congo red pollutants and can be a suitable candidate for various eco-friendly environmental applications.