Research on photodegradation of formaldehyde by nanocrystalline N-TiO2 powders under visible light irradiation

Abstract

The photo-degradation of formaldehyde (HCHO) by nitrogen-doped nanocrystalline TiO 2 (N-TiO 2 ) powders under visible light irradiation has been systematically investigated. Experimental results show that the degradation ratio reached up to 42.6% after 2 h visible light irradiation when the amounts of N-TiO 2 powders were 0.5 g, the initial concentration of the HCHO was set at 0.98 mg/m 3 , the illumination intensity was fixed at 10,000 lux, the ambient temperature was set at 26°C, and the relative humidity was maintained at 33 ± 5%. Further research shows that the degradation ratios were all larger than 40% in ten repeated cycles of photodegradation of HCHO by N-TiO 2 powders. The degradation ratio was as high as 82.9% after 2 h visible light irradiation when the amount of N-TiO 2 was 5 g. The degradation ratio was increased from 25.5 to 59.6% when the illumination intensity of the visible light was increased from 0 to 30,000 lux. However, the degradation ratio could not be further increased by further increasing the illumination intensity.

Removal of Indoor Volatile Organic Compounds via Photocatalytic Oxidation: A Short Review and Prospect

“…However, the influences of light intensity are seldom studied with visible light sources. The formaldehyde removal rates with N-doped TiO 2 photocatalyst were enhanced linearly form 25.5% to 59.6%, and stabilized thereafter, when the intensity increased to 30,000 lux with an initial concentration of 0.98 mg/m 3 [132].…”

Experimental study on visible-light induced photocatalytic oxidation of gaseous formaldehyde by polyester fiber supported photocatalysts

“…For visible light illuminated PCO reaction, the influence from light intensity is seldom discussed. Qu et al [45] studied the effect of visible light illumination on the photo-degradation of HCHO by a nitrogen doped TiO 2 photocatalyst. With HCHO initial concentration at 0.98 mg/m 3 (about 0.8 ppm at 20 ºC), the degradation increased linearly from 25.5% to 59.6% alongside an incrementing illumination intensity of 0-30,000 lux and stabilized thereafter.…”

Photocatalytic Oxidation of Gaseous Formaldehyde on TiO2: An In Situ DRIFTS Study

“…During the gaseous PCO of VOCs, this nanostructured TiO 2 exhibited high activity and selectivity. Qu et al [13] reported a nitrogen-doped nanocrystalline TiO 2 (N-TiO 2 ) using the hydrothermal method. The N-TiO 2 powders exhibited good cycling performance and no obvious deactivation tendency for the photo-degradation of formaldehyde.…”