Lyu, NingEdirisooriya, AnjalieFusco, ZelioLiu, DaweiFu, LanBeck, Fiona J.David, Christin2026-02-112026-02-11ORCID:/0000-0001-9631-938X/work/205112047ORCID:/0000-0002-9070-8373/work/205113473https://hdl.handle.net/1885/733805411Plasmonic-based metasurfaces play a crucial role in resonance-driven photocatalytic reactions by effectively enhancing reactivity via localized surface plasmon resonances. Catalytic activity can be modulated by tuning the strength of plasmonic resonances in two primary nonthermal mechanisms: near-field enhancement and hot-carrier injection, which govern the population of energetic carriers excited or injected into unoccupied molecular orbitals. A set of polarization-sensitive metasurfaces consisting of elliptical Au-TiO2 nanopillars, specifically designed to plasmonically modulate the reactivity of a model reaction: the photocatalytic degradation of methylene blue, is developed. Surface-enhanced Raman spectroscopy allows to indirectly assess the yield by monitoring the product peak and shows polarization-dependent yield rate modulated by a factor of 2 depending on the polarization – either x-/y-polarization in 10 s period, as quantified by the integrated area of the 480 cm−1 Raman peak and correlated with enhanced absorption at 633 nm. The single metasurface configuration enables continuous tuning of photocatalytic reactivity via active control of plasmonic resonance strength, as evidenced by the positive correlation between measured absorption and indicative product yield. This dynamic approach provides a route to tailor-enhance or suppress resonance-driven reactions, which can be further leveraged to achieve in multibranch reactions, guiding product yields toward desired outcomes.This work was supported by the German Research Foundation DFG (Deutsche Forschungsgemeinschaft) through funding of the International Research Training Group IRTG 2675 (GEPRIS 437527638). The authors acknowledge access to NCRIS facilities (ANFF‐ACT Node) at the Australian National University. The project is funded by International Research Training Group IRTG 2675 (GEPRIS 437 527 638).9en© 2026 The Author(s).localized surface plasmon resonanceplasmonic-based metasurfacepolarization-sensitive metasurfaceresonance-driven reactionstunable metasurface2026-01-2010.1002/adom.202503650105027881392