Active {001} Facet Exposed TiO₂ Nanotubes Photocatalyst Filter for Volatile Organic Compounds Removal: From Material Development to Commercial Indoor Air Cleaner Application

Abstract

TiO nanotubes (TNT) have a highly ordered open structure that promotes the diffusion of dioxygen and substrates onto active sites and exhibit high durability against deactivation during the photocatalytic air purification. Herein, we synthesized {001} facet-exposed TiO nanotubes (001-TNT) using a new and simple method that can be easily scaled up, and tested them for the photocatalytic removal of volatile organic compounds (VOCs) in both a laboratory reactor and a commercial air cleaner. While the surface of TNT is mainly composed of {101} facet anatase, 001-TNT's outer surface was preferentially aligned with {001} facet anatase. The photocatalytic degradation activity of toluene on 001-TNT was at least twice as high as that of TNT. While the TNT experienced a gradual deactivation during successive cycles of photocatalytic degradation of toluene, the 001-TNT did not exhibit any sign of catalyst deactivation under the same test conditions. Under visible light irradiation, the 001-TNT showed degradation activity for acetaldehyde and formaldehyde, while the TNT did not exhibit any degradation activity for them. The 001-TNT filter was successfully scaled up and installed on a commercial air cleaner. The air cleaner equipped with the 001-TNT filters achieved an average VOCs removal efficiency of 72% (in 30 min of operation) in a 8-m test chamber, which satisfied the air cleaner standards protocol (Korea) to be the first photocatalytic air cleaner that passed this protocol.

Inside‐and‐Out Semiconductor Engineering for CO2 Photoreduction: From Recent Advances to New Trends

“…First, surface atomic arrangements of specific facet have effect on the molecular adsorption and intermediate products. [ 305–308 ] Namely, the conversion and final products of CO 2 reduction can be tuned by exposed facets. Second, the band bending may occur on the surface, and diverse exposed facets are link to the redox abilities of charge carriers in reactions.…”

Dual-function surface hydrogen bonds enable robust O2 activation for deep photocatalytic toluene oxidation

“…, H 2 O 2 , or˙OH) are highly active in triggering indoor VOC oxidations. [10][11][12][13] Unfortunately, room-temperature photocatalytic VOC oxidation, particularly for those aromatic compounds, is not efficient enough with a tandem bottleneck associated with risky intermediate emission and catalyst deactivation. 11,12 Toluene is a representative of aromatic VOCs whose oxidation is shown to be difficult and intricate.…”

“…[10][11][12][13] Unfortunately, room-temperature photocatalytic VOC oxidation, particularly for those aromatic compounds, is not efficient enough with a tandem bottleneck associated with risky intermediate emission and catalyst deactivation. 11,12 Toluene is a representative of aromatic VOCs whose oxidation is shown to be difficult and intricate. Rather than being directly mineralized, toluene is usually decomposed stepwise through which undesirable carbonaceous intermediates are generated in situ.…”

Visible-light photocatalysis over MIL-53(Fe) for VOC removal and viral inactivation in air

“…Among them, photocatalytic oxidation is a powerful tool that by chemical reactions at ambient room temperature and pressure is capable of degrading (or mineralizing) VOCs, as well as inactivating microorganisms [6,20]. For the photocatalytic treatment of VOCs and microorganisms, titania (TiO 2 ) has been most intensively studied [21][22][23][24][25][26][27][28]. However, TiO 2 , of which the bandgap is 3.03.2 eV, can only utilize UV light [6,29], which limits versatile applications of the photocatalyst.…”