Plasmonic Au nanoparticles supported on both sides of TiO2 hollow spheres for maximising photocatalytic activity under visible light

Jianwei Lu,Xiaoteng Terence Liu,Lan Lan,Xiaolei Fan,Na Wang

doi:10.1007/s11705-019-1815-2

Abstract

A strategy of intensifying the visible light harvesting ability of anatase TiO2 hollow spheres (HSs) was developed, in which both sides of TiO2 HSs were utilised for stabilising Au nanoparticles (NPs) through the sacrificial templating method and convex surface-induced confinement. The composite structure of single Au NP yolk-TiO2 shell-Au NPs, denoted as Au@Au(TiO2, was rendered and confirmed by the transmission electron microscopy analysis. Au@Au(TiO2 showed enhanced photocatalytic activity in the degradation of methylene blue and phenol in aqueous phase under visible light surpassing that of other reference materials such as Au(TiO2 by 77% and Au@P25 by 52%, respectively, in phenol degradation.

Highlights

Titanium dioxide is a semiconductor that has attracted increasing interests in photocatalytic and photovoltaic applications [1,2,3,4] because of the great oxidative potential of its positive holes (E = + 3.0 V versus standard hydrogen electrode) [5], especially in the anatase form
We demonstrate the design and synthesis of plasmonic Au-TiO2 HSs nanostructure with Au NPs deposited on both sides of the anatase TiO2 HS, i.e., a single encapsulated Au core and multiple Au NPs confined by the convex curved outer surface of the TiO2 HS, denoted as Au@Au(TiO2 (@ represents the deposition of Au NP on HSs), to improve the photocatalytic efficiency of the system
The precipitated silica nanoparticles were extracted by centrifugal separation and washed with ethanol redispersed in 5 mL of ethanol

Summary

Introduction

Due to the wide band-gap of 3.2 eV (for the anatase form) [6], TiO2 has trivial response to the visible light (wavelength: 390–700 nm) [7,8] hindering the develop-. The integration of plasmonic gold or silver nanoparticles (NPs) with TiO2 [8,17,18,19,20,21,22] have been proposed to enhance the photocatalytic and photovoltaic activity in the visible region due to the strong surface plasmon resonance (SPR) excitation of such metal NPs, by which can enhance the concentration of charge carriers. One specific example presented by Zhang et al [22] is the hybrid plasmonic Au nanoparticle (NP)-loaded hierarchical hollow porous TiO2 spheres, which showed the enhanced the overall catalytic activity in 4-nitrophenol reduction [22].

Methods

Results

Conclusion