How Do Ionic Liquids Affect the Surface Structure of Titania Photocatalyst? An Electron-Trap Distribution-Analysis Study

Adriana Zaleska-Medynska,Bunsho Ohtani,Guangyi Chen,Mai Takashima,Justyna Łuczak,Anna Pancielejko

doi:10.1021/acs.jpcc.1c09174

Abstract

Titanium(IV) oxide, titania, photocatalyst particles were prepared from titanium alkoxide in the presence of several kinds of ionic liquids, and it was clarified that a group of samples exhibited photocatalytic activity for phenol degradation under the irradiation of light of wavelength >400 nm higher than those of the other group of samples. Although the conventional structural analytical results could not be related to the activity, electron-trap distribution measured by reversed double-beam photoacoustic spectroscopy suggested that a part of the ionic liquid induced the creation of a surface amorphous layer covered with hydrophobic organic residues to enhance the adsorption of phenol on the surface.

Highlights

Surface properties of advanced materials are crucial for their activities regarding relevant applications, especially when chemical reactions occur on the surface
We characterized the surface and bulk electronic properties of the titania photocatalysts modified with the selected ionic liquids using the reversed double-beam photoacoustic spectroscopy (RDB-PAS) technique to obtain ERDT patterns as a fingerprint of different ILs used for synthesis as well as IL-titania precursor (TBOT) molar ratio
Physical and Structural Properties Measured by Conventional Analytical Methods

Summary

■ INTRODUCTION

Surface properties of advanced materials are crucial for their activities regarding relevant applications, especially when chemical reactions occur on the surface. One of the premises is the relatively low thermal stability of IL under the preparation conditions (possible decomposition).[10] there are ILs which are thermally stable and still reveal relatively high photoactivity In this regard, we characterized the surface and bulk electronic properties of the titania photocatalysts modified with the selected ionic liquids using the RDB-PAS technique to obtain ERDT patterns as a fingerprint of different ILs used for synthesis as well as IL-titania precursor (TBOT) molar ratio. We characterized the surface and bulk electronic properties of the titania photocatalysts modified with the selected ionic liquids using the RDB-PAS technique to obtain ERDT patterns as a fingerprint of different ILs used for synthesis as well as IL-titania precursor (TBOT) molar ratio For these experiments, the IL-titania samples with exceptionally high photoactivity determined by the model phenol degradation reaction under vis irradiation were selected. To determine the absorption edge wavelength, the bandgap energy in the unit of eV was calculated and plotted as CBB regarding VBT as shown in, e.g., Figure 1

■ RESULTS AND DISCUSSION

■ CONCLUSIONS

■ REFERENCES