Optimizing Nanoscale TiO₂ for Adsorption‐Enhanced Photocatalytic Degradation of Low‐Concentration Air Pollutants

Abstract

Adsorption and photodegradation are key steps in environmental air purification. Micropores have been introduced into anatase TiO2 nanocatalysts to enhance the adsorption of pollutant molecules onto the photocatalyst surface, which increases the use of the photoinduced electron–hole pairs. Three nanocomposites have been synthesized with dodecylamine as a pore‐forming agent under mild hydrothermal conditions and at varying temperature of preparation. Samples synthesized at 100, 115, and 130 °C, labeled TiO2‐100, TiO2‐115, and TiO2‐130, respectively, provided insights into the effect of crystallinity and micropore area on the removal efficiency of gas‐phase organic pollutants. Of the three, TiO2‐100 had the largest micropore area (493 m2 g−1) but amorphous phase. TiO2‐130 had anatase phase but only mesopores, whereas TiO2‐115 had both a relatively large micropore area (258 m2 g−1) and an anatase crystal structure. Toluene was chosen as a model air pollutant. Experiments were performed in a single‐pass reactor in the presence of UV irradiation under various experimental conditions, such as varying partial pressures of toluene, contact times, and relative humidities of the mobile gas phase, to approximate realistic conditions for this air purification system. Of the three prototype catalysts, TiO2‐115 showed the highest removal and mineralization efficiencies owing to the optimized availability of photogenerated holes and adsorbed toluene. The key parameters for optimized photocatalysis of low‐concentration air pollutants are the micropore area and the crystallinity of the photocatalyst.

Floating photocatalyst of B–N–TiO2/expanded perlite: a sol–gel synthesis with optimized mesoporous and high photocatalytic activity

“…However, the materials of large-sized pores with low specific surface area also have low photocatalytic activity, as TiO 2 –EP we obtained. Even the microporous TiO 2 with high surface area also tend to have an amorphous character, and the micropores easily collapse 36 . Miao et al .…”

Cotton derived carbonaceous aerogels for the efficient removal of organic pollutants and heavy metal ions

“…It can be seen that CDPC and CDPCO possess large amounts of micropores in their structures and the pores disappeared aer MB adsorption, which could be regarded as evidence of the micropore occupation by MB molecules. 18 FT-IR spectra of the adsorbents before and aer adsorption were obtained to identify the adsorption mechanism. As shown in Fig.…”

Preparation of TiO2 and Fe-TiO2 with an Impinging Stream-Rotating Packed Bed by the Precipitation Method for the Photodegradation of Gaseous Toluene

“…Because of its high chemical stability and high photocatalytic activity, nano-TiO 2 has great development prospects in the fields of environmental protection [1], such as in photocatalytic disinfection, antibacterial use [2,3], wastewater treatment [4], air purification [5], and so on. Especially in the face of the current difficulty of eliminating volatile organic compound (VOC) pollution in the air, TiO 2 photocatalysis technology has shown unique advantages [6,7].…”