Multifield Coupling of Local Surface Plasmon Resonance‐Assisted Au–TiO ₂ Photocatalysis Considering Bimodal Resonance and Superposition Effect

This study concerns the improvement of the synergetic catalytic efficiency of Au–TiO2 nanorods considering the local surface plasmon resonance (LSPR) effect of different Au nanoparticles (NPs). The absorption spectrum and selective absorption efficiency for visible light, the local electric field, and the generated thermal effect are specifically analyzed based on the multifield decoupling of LSPR-assisted Au–TiO2 catalysts. The simulation results show that the extinction spectra of both spherical and ellipsoidal Au particles are consistent with the experimental data. Interestingly, the latter is characterized by significant bimodal resonance modes. Comparatively, the simulation results show that the longitudinal mode, which is sensitive to the aspect ratio, is more favorable for the improvement of the photocatalytic activities. It is found that the resonance peaks are highly controllable, and are linear to the particle size and aspect ratio. Meanwhile, the electric field mode of TiO2 is significantly increased under the resonance wavelength. It is worth mentioning that the superposition effect makes a non-negligible impact on the actual catalysts, leading to a relative shift of resonance wavelength. The consideration of the hot spots caused by the superposition effect influence the photocatalytic results significantly, providing values in diminishing the inadaptability of the theory in near-touching regions of plasma particles.