基于Er3+∶YAlO3/TiO2的可见光催化降解室内甲醛

Abstract

In order to develop the photocatalytic activity of TiO2 under visible light as that under ultraviolet light to degrade indoor ormaldehyde pollution,a visible light response photocatalyst consisting of TiO2 and upconversion luminescence agent Er3+∶ YAlO3 was prepared using hydrothermal treatment method. The photocatalyst was characterized by X-ray diffractometer( XRD),UV-Vis diffuse reflectance spectrophotometer( DRS) and fluorescence spectrometer( FS). The prepared TiO2 is anatasedominant. Er3+∶ YAlO3 can convert visible light to ultraviolet( UV) light to expand the absorption range of TiO2. The upconverted UV light can excite TiO2 effectively to produce active materials with strong oxidation ability. The photocatalyst was applied to degrade gaseous formaldehyde in the sealed reactor,and the effect of initial formaldehyde concentration and photocatalyst dosage on the degradation efficiency of formaldehyde were investigated. The results show that the prepared photocatalyst can efficiently degrade the formaldehyde. The apparent first order reaction rate constant for gaseous formaldehyde degradation is positively correlated with the initial formaldehyde concentration,but increases first then decreases with the increasing of photocatalyst dosage from 0. 061 2 g / L to 0. 234 8 g / L.When the formaldehyde concentration is 0. 058 mg / m3 and the photocatalyst dosage is 0. 122 4 g / L,the apparent first order reaction rate constant is the biggest of 3. 65 × 10- 3min-1. The degradation follows Langmuir-Hinshelwood model,and the reaction rate constant is 5 × 10- 8mg /( L·min).