Fabrication of Ag-modified hollow titania spheres via controlled silver diffusion in Ag-TiO2 core-shell nanostructures.

Bartosz Bartosewicz,Bogusław Budner,Krzysztof Kopczyński,Marta Michalska-Domańska,Malwina Liszewska,Bartłomiej J Jankiewicz

doi:10.3762/bjnano.11.12

Abstract

Inorganic hollow spheres find a growing number of applications in many fields, including catalysis and solar cells. Hence, a simple fabrication method with a low number of simple steps is desired, which would allow for good control over the structural features and physicochemical properties of titania hollow spheres modified with noble metal nanoparticles. A simple method employing sol–gel coating of nanoparticles with titania followed by controlled silver diffusion was developed and applied for the synthesis of Ag-modified hollow TiO2 spheres. The morphology of the synthesized structures and their chemical composition was investigated using SEM and X-ray photoelectron spectroscopy, respectively. The optical properties of the synthesized structures were characterized using UV–vis spectroscopy. Ag–TiO2 hollow nanostructures with different optical properties were prepared simply by a change of the annealing time in the last fabrication step. The synthesized nanostructures exhibit a broadband optical absorption in the UV–vis range.

Highlights

Recent examples of the fabrication of plasmonic NP-modified TiO2 hollow spheres (HSs) are based mainly on multistep processes including hard-templating methods [10,11,12,13,14,15,16,17,18,19]
Of great interest are TiO2 HSs modified with plasmonic nanoparticles (NPs), which allow for the combination of the photocatalytic properties of TiO2 and the optical properties of plasmonic NPs [2]
This combination has been shown to extent the photocatalytic activity of TiO2, which is initially limited to UV light [8], to the visible or even to the NIR range of radiation [9]

Summary

Introduction

Recent examples of the fabrication of plasmonic NP-modified TiO2 HSs are based mainly on multistep processes including hard-templating methods [10,11,12,13,14,15,16,17,18,19]. The metal diffusion into the titania shell has not been observed in the case of Au@TiO2 CSNs fabricated using the same method as Ag@TiO2 CSNs. This is likely due to much lower reactivity of Au compared to Ag. Ag–TiO2 nanostructures at an intermediate and the final stage of thermal modification are shown in SEM images in Figure 1 and Figure 2B–E.

Results

Conclusion