Core-shell synergy and Eu3+ doping in boosting charge transfer in Eu3+ doped TiO2-carbon core-shell nanohybrids: Sustainable synthesis and visible light-driven photocatalysis

Abstract Core-shell nanostructures have gained enormous research interest owing to a synergetic interfacial interaction resulting in enhanced functionalities, particularly optical and optoelectronic, and sometimes exotic properties. The investigation reports on a sustainable synthesis of Eu3+ doped TiO2‑carbon core-shell nanohybrids (0.5–2.0 mol% Eu3+) using a simple green-chili-based biogenic method. The crystal structure, morphology, optical properties are systematically studied using X-ray diffraction, Electron microscopy, UV–visible light absorption spectrophotometry, photocurrent and electrochemical impedance measurement. The roles of carbon shell and Eu3+ ions in boosting the photocatalytic activity of the nanohybrids are studied and analysed by evaluating their degradation performance under visible light using methylene blue (MB) and 2-cholorophenol (2-CP) as target water pollutants. 1.5 mol% Eu3+ doped core shell nanohybrid, annealed at 600 °C exhibits highest removal efficiency 91.5% and 76.8% for MB and 2-CP respectively. The analysis in correlation with the properties studied reveals that a strong core-shell interfacial coupling and Eu3+ doping boosts up the photo-induced charge carrier generation and separation that enhances degradation performance of the sample. The degradation efficiency and rate are nearly three and five times of that of bare TiO2. The work demonstrates a sustainable development of core-shell nanohybrids showing a scope for solar light-driven photocatalytic applications.