Enhanced Photocatalysis of TiO2 by Aluminum Plasmonic

Abstract Al nanoparticles composited with TiO2 (Al-NPs/TiO2) has drawn considerable attention over the years due to the localized surface plasmon resonance (LSPR) effect of Al-NPs can significantly enhance the photocatalytic efficiency of TiO2. However, most of the Al-NPs were obtained on Al substrates which limited its practical application. Herein, the isolated Al-NPs were composited together with the TiO2 by using glutathione (GSH) as linking bridge in aqueous environment. Finite difference time domain (FDTD) simulation was used to reveal the LSPR absorption of Al-NPs. The results show that the LSPR of 70 nm Al-NPs have a strong coupling with the TiO2 band gap. The X-ray diffraction analysis and TEM images show that our sample are pure, and the TiO2 indeed composite on the surface of Al-NPs under the action of GSH ligand bridge as seen in the TEM images. This ligand bridge was further verified by the FTIR and XPS measurements. The EPR experiment indicate the •OH signals of Al-NPs/TiO2 are higher than that of pure TiO2 because of enhanced charge separation and transfer. The photodegradation experiment show that Al-NPs/TiO2 can rapidly degrade the concentration of methylene blue (MB) to zero under UV-visible light illumination in 70 minutes. All the above results indicate that the Al-NPs can significantly enhance the photocatalytic efficiency of TiO2 which due to the LSPR effect of Al.