EGCG/ECG-controlled mesoporous and ultrafine TiO₂ nanoparticles for UV-driven pollutant mineralization and radical scavenging
Sumit Thakur, Jyoti Gaur, Anand Somvanshi, Suhas Ballal, Kishor Kumar Sadasivuni, Kasim Sakran Abass, Pramod Kumar, Sandeep Kaushal, Sanjeev Kumar
Abstract
We report the first phytochemical-guided, one-pot sol–gel/hydrothermal synthesis of mesoporous anatase TiO2 nanoparticles (< 10 nm) directed by catechin-rich fractions (epigallocatechin-3-gallate (EGCG), epicatechin-3-gallate (ECG), epigallocatechin (EGC)) identified through GC–MS of a TV-26 Camellia sinensis extract. These small-molecule bio-templates drive uniform Ti4⁺ nucleation, arrest crystal growth, and remain grafted to the oxide surface, producing a high specific surface area (160 m2 g−1) and a stable polyphenol corona. Comprehensive characterization (XRD, UV–Vis-DRS, FTIR, BET, SEM/TEM) confirms the phase-pure anatase and a narrow size distribution (6–9 nm). The bio-templated TiO2 attains > 98% mineralization of methylene blue under near-UV irradiation (365 nm, 65 mW cm⁻2) within 45 min, giving a pseudo-first-order rate constant k = 0.0567 min−1, more than double that of commercial P25 under identical conditions. Surface-bound catechins impart intrinsic antioxidant activity, with IC₅₀ values of 34.7 ± 1.2 µg mL−1 (DPPH) and 29.3 ± 0.9 µg mL−1 (ABTS). By uniting green synthesis, size-controlled mesoporosity, and dual photocatalytic/radical-scavenging functionality, this work positions phytochemical-engineered TiO2 as a versatile platform for next-generation water remediation and biomedical technologies.