Photodegradation of dye acridine yellow on the surface of mesoporous TiO2, SiO2/TiO2 and SiO2 films: spectroscopic and theoretical studies

E M Demianenko,N I Surovtseva,N P Smirnova,A G Grebenyuk,A M Eremenko,T V Fesenko

doi:10.1007/s40097-015-0165-y

Abstract

Electronic spectra and LDI mass spectra changes accompanying photodegradation of acridine yellow (AY) adsorbed on the surface of prepared via templated sol–gel synthesis TiO2, SiO2, and TiO2/SiO2 mesoporous films have been investigated and the main photodegradation products have been determined. The results of calculations show the adsorption energy of the molecular state of AY to be the greatest for the complex with titania–silica where Lewis acidic sites are present, the smallest one being related to the complex with titania what corresponds to the experimental data. Effectiveness of acridine yellow photodegradation on the surfaces of mesoporous films under UV irradiation increases in a row SiO2 < TiO2/SiO2 < TiO2. Electronic and laser desorption/ionization mass spectra and theoretical modeling give evidence that efficient photobleach of AY localized at the surface of anatase films proceeds through the following steps: 1—N-demethylation/deamination; 2—photodimerization; 3—photodegradation.

Highlights

Acridine dyes have ubiquitous use as colorant for synthetic fibers, tissue, leather, fluorophores with high fluorescence intensity in luminescent analysis [1,2,3]
Gradual improvements of solar cell and photocatalyst efficiency have been achieved with the development of the synthetic route to prepare the mesoporous TiO2 film consisting of nanosized semiconductor particles or TiO2/SiO2 nanocomposite films where silica matrix provides the transport of reagents to TiO2 nanoparticles via developed porous structure
For TiO2/SiO2, SiO2 films calcined at 350 °C, and TiO2 at 500 °C adsorption–desorption isotherms have two hysteresis loops: the first one at high pressures of hexane which indicates the presence of mesopore and the second loop at low pressures, which indicates the irreversible structural deformation of films and formation of the so

Summary

Introduction

Acridine dyes have ubiquitous use as colorant for synthetic fibers, tissue, leather, fluorophores with high fluorescence intensity in luminescent analysis [1,2,3]. The calculated adsorption energy of acridine yellow molecular form is the greatest in case of titania–silica surface where Lewis sites are present, the last one relates to titania surface.

Results

Conclusion