Optical absorption enhancement of TiO2 via plasmonic effect of gold nanoparticles in volatile organic compounds medium

Abstract

Controlling volatile organic compounds (VOC) is of utmost importance due to their adverse impacts on human health and environment. Photocatalytic degradation using TiO2 nanoparticles has emerged as a promising approach for VOC control. However, the limited photocatalytic activity of TiO2 under visible light owing to its wide bandgap presents a significant challenge. To address this limitation, the integration of plasmonic materials with TiO2 enables efficient hot electron injection into TiO2 under visible light. In this study, we investigate the influence of gold nanoparticles (AuNP) on TiO2-based structures, namely AuNP-decorated TiO2 thin films, Au@TiO2 core@shell structures, and AuNP-loaded TiO2 nanoparticles, using finite difference time domain (FDTD) simulations. Simulation results demonstrate that the presence of AuNP in TiO2 structures reduces the bandgap and enhances light absorption. Moreover, the localized electric field enhancement observed at the AuNP-TiO2 interface indicates the potential for effective hot electron injection into TiO2. Additionally, simulations conducted in a VOC medium demonstrate higher absorption compared to vacuum conditions. This work provides insights into the mechanisms underlying previously published experiments and proposes an appealing design for the development of highly efficient photocatalytic materials under visible light.