Persistent deNOx Ability of CaAl2O4:(Eu, Nd)/TiO2-xN y Luminescent Photocatalyst

Huihui Li,Shu Yin,Tsugio Sato

doi:10.1007/s11671-010-9750-7

Abstract

CaAl2O4:(Eu, Nd)/TiO2-xNy composite luminescent photocatalyst was successfully synthesized by a simple planetary ball milling process. Improvement of photocatalytic deNOx ability of TiO2-xNy, together with the persistent photocatalytic activity for the decomposition of NO after turning off the light were realized, by coupling TiO2-xNy with long afterglow phosphor, CaAl2O4:(Eu, Nd). The novel persistent photocatalytic behavior was related to the overlap between the absorption wavelength of TiO2-xNy and the emission wavelength of the CaAl2O4:(Eu, Nd). It was found that CaAl2O4:(Eu, Nd)/TiO2-xNy composites provided the luminescence to persist photocatalytic reaction for more than 3 h after turning off the light.Graphical CaAl2O4:(Eu, Nd)/TiO2-xNy composite luminescent photocatalyst with persistent deNOx activity after turning off the light was successfully synthesized by a simple planetary ball milling process. The novel persistent photocatalytic behavior was related to the overlap between the absorption wavelength of TiO2-xNy and the emission wavelength of the CaAl2O4:(Eu, Nd).

Highlights

Hot photocatalytic research attention has been focused on titania (TiO2), because of its chemical stability [1], excellent photocatalytic activity [2] and low cost
Since titania has large band gap energy of about 3.2 eV corresponding to the wavelength of 387.5 nm, it is active under irradiation of only UV light less than 400 nm of wavelength
Various modifications have been devoted to TiO2 in extending the absorption edge into visible light and enhancing the photocatalytic activity [8,9,10,11,12,13], and one of them is doping TiO2 with nitrogen because the band gap of titania could be narrowed by doping with nitrogen ion since the valence band of N2p band locates above O2p band [14]

Summary

Introduction

Hot photocatalytic research attention has been focused on titania (TiO2), because of its chemical stability [1], excellent photocatalytic activity [2] and low cost. The coupling of TiO2 with CaAl2O4:(Eu, Nd) was expected to prolong the photocatalytic activity even after turning off the light by using the persistent emitting luminescence of the long afterglow phosphor as a light source of TiO2 photocatalyst.

Results

Conclusion