In-situ monitoring of plasmon-induced nanoscale photocatalytic activity from Au-decorated TiO₂ microflowers

Abstract

Noble metal decorated semiconductor photocatalysts have paid noticeable attention owing to their enhanced photocatalytic activity. Herein, we have synthesized pure rutile phase of TiO2 nanorods composed microflowers morphology by hydrothermal method and decorated them with Au to observe plasmon-induced enhanced photocatalytic efficiency. The optical bandgap engineering through Au decorated TiO2 introduced midgap states, that helps in charge compensation during photodegradation study. The surface plasmonic resonance peak of Au is observed along with the defect peak of TiO2, extending the absorption of the solar spectrum from UV to the visible region. The quenching in photoluminescence intensity with increased Au thickness indicates the formation of Schottky junction at the interface of Au and TiO2 that helps in reducing photo-generated charge carrier recombination. The softening of the Eg Raman mode and photothermal effect originated from the non-radiative decay of localized surface plasmon through electron-phonon and phonon-phonon relaxation. The photocatalytic degradation of Rhodamine 6G (R6G) is monitored by exposing the sample to UV and visible light sources under Raman spectroscopy. The Au decoration plays a crucial role in promoting charge separation, Schottky junction creation, photothermal effect, and UV to visible light absorption to enhance photocatalytic activity, which can be explained on the basis of the charge transfer mechanism. Our in-situ photo-degradation study at the interface of noble metal and semiconducting materials will pave the way to improve the understanding of plasmon-enhanced photocatalytic applications.

Plasmon mediated SERS and photocatalysis enhancement in Au nanoparticle decorated 2D-TiSe2

“…Other materials such as MoS 2 , SnS, SnSe, and SnS 2 shows significant photocatalytic performance [12][13][14][15][16]. Several oxide semiconductors (TiO 2 , ZnO, Fe 2 O 3 , CdS, ZnS, SnO 2 ) also functioned as photocatalysts [17][18][19][20][21][22][23][24]. However, their limited capacity to absorb visible light radiation inhibits their usefulness in outdoor applications [25,26].…”