Sustainable synthesis of CeO2@N-carbon hybrid from cashew fruit byproducts for enhanced photocatalytic and antibacterial applications
摘要
Water pollution caused by toxic dyes, heavy metals, and microorganisms has become a serious environmental problem, creating an urgent need for effective wastewater treatment materials. This study presents a sustainable synthesis of a multifunctional CeO2@N-doped carbon (CeO2@NC) hybrid nanocomposite utilizing Anacardium occidentale (cashew) juice as a reducing agent and cashew nut shell waste as a nitrogen-rich carbon precursor. X-Ray Diffraction (XRD) investigation verified the cubic fluorite structure of CeO2 with a crystallite size of around 28 nm, which diminished to around 21 nm in the CeO2@NC composite as a result of carbon matrix interaction. The structural analysis validated the effective incorporation of nitrogen-functional groups (pyridinic-N, graphitic-N) and Ce–O bonding. Morphological analysis demonstrated evenly disseminated CeO2 nanoparticles (8–15 nm) anchored on porous NC sheets. BET analysis indicated a surface area increase from 38.5 m²/g (CeO2) to 112.4 m2/g (CeO2@NC) and a narrow mesopore distribution (~ 3.6 nm). UV–Vis DRS analysis demonstrated an increased light absorption accompanied by a reduced band gap, decreasing from 3.61 eV (CeO2) to 2.99 eV (CeO2@NC). The CeO2@NC composite demonstrated exceptional photocatalytic degradation of Malachite Green (94%) and Cr (VI) (97%) under visible light in 60 min, with pseudo-first-order rate constants of 0.0421 and 0.0485 min⁻¹, respectively. The material exhibited significant antibacterial efficacy against E. coli (19 mm) and S. aureus (17 mm) attributed to synergistic reactive oxygen species (ROS) production and improved charge mobility. The findings underscore the CeO2@NC hybrid as an economical, environmentally benign, and reusable material for concurrent photocatalytic and antibacterial applications in environmental remediation.