Eco-friendly synthesis of CeO2–TiO2 heterojunction nanocomposite with enhanced visible-light photocatalytic degradation of methylene blue and ciprofloxacin

Oct 8, 2026

Green hydrothermal synthesis uses Withania coagulans extract as a bio-reducing and stabilising agent to prepare CeO2, TiO2, and CeO2–TiO2 nanocomposites. XRD, HRTEM, and XPS confirm cubic fluorite CeO2 and anatase TiO2 coexistence, lattice coherence, and CeO2–TiO2 heterostructure formation. Oxygen vacancies and strong interfacial charge transfer enhance visible-light photocatalytic performance. The CeO2–TiO2 (1.5:0.5) composite achieves 93.17% CIP and 96.01% MB degradation with dominant ⋅OH and O2⋅−, outperforming single oxides and showing stability for five cycles.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages16

Reading Time40 min

AccessFree to download

Introduction

Photocatalysis and advanced oxidation processes (AOPs)

Limitations of conventional wastewater treatment

Heterogeneous catalysis and semiconductor catalysts

J Mater Sci: Mater Electron (2026) 37:1526 Eco‑friendly synthesis of CeO2–TiO2 heterojunction nanocomposite with enhanced visible‑light photocatalytic degradation of methylene blue and ciprofloxacin P. N. Kannan1 and Chandrasekaran Sivasankari1,* 1 Department of Chemistry, Government College of Technology, Coimbatore, TamilNadu 641013, India Received: 23 March 2026 Accepted: 21 June 2026 Published online: 10 July 2026 © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature, 2026 1 Introduction ABSTRACT In this work, CeO2, TiO2, and CeO2–TiO2 nanocomposites were successfully synthesised via a green hydrothermal route using Withania coagulans extract as a bio-reducing and stabilising agent. X-ray diffraction (XRD) confirmed the coexistence of cubic fluorite CeO2 and anatase TiO2 phases, whilst HRTEM revealed well-defined lattice fringes corresponding to both metal oxides, indicating strong interfacial contact within the composites. XPS analysis confirmed the successful formation of the CeO2–TiO2 heterostructure and revealed the coexistence of Ce3+/ Ce4+ and Ti4+ species. The presence of oxygen vacancies and strong interfacial interactions facilitated charge transfer, contributing to enhanced photocatalytic activity. The CeO2–TiO2 (1.5:0.5) nanocomposite exhibited enhanced visible-light absorption and improved surface properties, attributed to synergistic interactions and efficient charge separation. Photocatalytic activity was evaluated against ciprofloxacin (CIP) and methylene blue (MB), where the CeO2–TiO2 (1.5:0.5) composite showed the highest degradation efficiencies of 93.17%(CIP) and 96.01%(MB), with superior pseudo-first-order rate constants compared to pure CeO2 and TiO2. Reactive oxygen species (⋅OH and O2 ⋅ − ) were identified as the dominant contributors to pollutant degradation. The catalyst also demonstrated excellent stability and reusability over five consecutive cycles. These results highlight the potential of green-synthesised CeO2–TiO2 nanocomposites as efficient and sustainable photocatalysts for wastewater treatment applications. complicates this issue by altering precipitation patterns and intensifying droughts [2] . The depletion As the global population increases, the demand for freshwater resources grows, exacerbating water scarcity in many regions [1] . Climate change further of aquifers and the over-extraction of surface water sources have left numerous communities with limited access to clean water [3] . Rapid industrialisation and Address correspondence to E-mail: [sivasankarigct@gmail.com](sivasankarigct@gmail.com) [https://doi.org/10.1007/s10854-026-17866-w](https://doi.org/10.1007/s10854-026-17866-w) 1526 Page 2 of 16 J Mater Sci: Mater Electron (2026) 37:1526 urbanisation have led to the continuous discharge of large quantities of wastewater containing dyes, pharmaceuticals, pesticides, and other hazardous organic pollutants into aquatic environments [4] . These contaminants pose serious risks to ecosystems and human health due to their toxicity, persistence, non-biodegradability, and potential bioaccumulation. In particular, dye-contaminated wastewater from textile, printing, and chemical industries reduces light penetration in water bodies and adversely affects aquatic life [5, 6] Conventional wastewater treatment techniques such as adsorption, coagulation, membrane filtration, and biological treatment often suffer from limitations, including incomplete pollutant removal, high operational costs, and secondary waste generation. Therefore, the development of efficient and environmentally sustainable treatment technologies has become increasingly important. Amongst various advanced treatment strategies, photocatalysis has emerged asa promising approach because of its ability to utilise light energy for the degradation and mineralisation of organic pollutants into less harmful products, offering a sustainable solutio

FAQs

What method and role does Withania coagulans extract play in the synthesis?

The CeO2, TiO2, and CeO2–TiO2 nanocomposites are synthesized via a green hydrothermal route using Withania coagulans extract as a bio-reducing and stabilising agent.

How is the CeO2–TiO2 heterostructure confirmed?

XRD confirms coexistence of cubic fluorite CeO2 and anatase TiO2 phases, HRTEM shows lattice fringes from both oxides indicating strong interfacial contact, and XPS verifies heterostructure formation and Ce3+/Ce4+ and Ti4+ species.

Which photocatalytic mechanism dominates pollutant degradation and how effective is the best composite?

Reactive oxygen species, mainly ⋅OH and O2⋅−, dominate degradation. The CeO2–TiO2 (1.5:0.5) nanocomposite shows the highest efficiencies, reaching 93.17% for ciprofloxacin and 96.01% for methylene blue, with superior pseudo-first-order rate constants and stability over five cycles.

Oct 8, 2026

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