Single‐Step Continuous‐Flow Strain Engineering of Multiphase Titanate–TiO ₂ ‐Reduced Graphene Oxide Nanocomposites for Dual Photo‐ and Mechanocatalytic Activity

Strain engineering is an effective strategy to tune the electronic structure and catalytic performance of functional materials. Here, we demonstrate a single‐step continuous hydrothermal flow synthesis (CHFS) that produces multiphase titanate‐TiO ₂ ‐reduced graphene oxide (rGO) nanocomposites capable of both photocatalytic and mechanocatalytic activity. In this approach, in situ KOH‐mediated reduction of graphene oxide introduces interfacial lattice strain and directs the co‐crystallisation of anatase TiO ₂ , layered K ₂ Ti ₄ O ₉ , and metastable TiO ₂ (B). The resulting multiphase composites feature strain gradients and nanoscale heterojunctions that enhance visible‐light absorption, charge separation, and mechanically assisted catalytic response. Density functional theory (DFT) simulations confirm strain‐induced bandgap narrowing and charge redistribution at oxide–2D interfaces. Under simultaneous visible‐light irradiation and mechanical stirring, these hybrids achieved near‐complete degradation of concentrated aqueous methylene blue (0.04 mM) within 60 min, with an apparent dual‐mode rate constant of 0.1046 min ⁻¹ , outperforming conventional photocatalysts. This single‐step, scalable platform provides a general route to design multifunctional catalysts for environmental remediation and solar‐to‐chemical energy conversion.