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

In the present study, we aimed to investigate the photocatalytic behavior of a novel bimetal-biopolymer nanocomposite of cellulose/γ–Fe 2 O 3 –ZrO 2 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-ZrO 2 significantly decreased the optical bandgap of nano-γ–Fe 2 O 3 from 4.90 eV to 2.28 eV at the γ–Fe 2 O 3 :ZrO 2 ratio of 1:1. Although the effect of nanocellulose on the energy bandgap of γ–Fe 2 O 3 –ZrO 2 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:Fe 2 O 3 –ZrO 2 ratio of 1:1. These results showed that the cellulose/γ–Fe 2 O 3 –ZrO 2 nanocomposite demonstrated a higher photodegradation efficiency of Congo red under visible light than γ–Fe 2 O 3 –ZrO 2 , nano-γ–Fe 2 O 3 , and nano-ZrO 2 . Briefly, our results confirm that the cellulose/γ–Fe 2 O 3 –ZrO 2 nanocomposite shows good photocatalytic activity toward the degradation of Congo red pollutants and can be a suitable candidate for various eco-friendly environmental applications. • Cellulose/γ–Fe 2 O 3 –ZrO 2 nanocomposite was studied for improved visible light-driven degradation of Congo red. • Rice straw was used as a cellulose source. • The optical bandgap decreases significantly from 4.90 eV to 2.20 eV at the γ–Fe 2 O 3 /ZrO 2 (1:1) ratio. • The optimal catalyst afforded a high Congo red (CR) degradation of 98.5% in 30 min.