Inorganic-organic nanofiber networks with antibacteria properties for enhanced particulate filtration: The critical role of amorphous titania

The demand for air filter media at indoor and outdoor is increasing tremendously due to air pollution and especially for problems related to airborne particulate matter (PM). To realize that, here a class nanofiber air filter media with strong antibacterial activity, hydrophobic nature, high filtration efficiency with low pressure drop is prepared. Novel organic-inorganic nanocomposite nanofibers used in this work benefited for the multifunctional performance. Amorphous titanium dioxide (mTiO₂) is utilized for air filtration application which exhibits excellent enhancement of PM_2.5 filtration properties and antibacterial activity. The unique Poly (vinylpyrrolidone) (PVP)-mTiO₂ nanofiber air filter media acquired hydrophobic nature with a large increase in water contact angle of 127° from 36°. The resulting free-standing nanofiber filters exhibit high PM_2.5 filtration efficiency of >99.9% and low pressure drop of 39 Pa. Antibacterial activity of nanofibrous membrane has been rationally engineered by titanium oxide as the barrier to bacterial ingression. A long term of 160 h filtration test has proved PVP-mTiO₂ nanofibers air filter media holds outstanding 99% filtration efficiency for PM_2.5. This work takes forward a significant lead in design and production of high performance and very low pressure drop air filter media with a wide range of functional properties.

Mechanistic insights into water adsorption and dissociation on amorphous -based catalysts

Despite having defects, amorphous titanium dioxide ([Formula: see text]) have attracted significant scientific attention recently. Pristine, as well as various doped [Formula: see text] catalysts, have been proposed as the potential photocatalysts for hydrogen production. Taking one step further, in this work, the author investigated the molecular and dissociative adsorption of water on the surfaces of pristine and [Formula: see text] doped [Formula: see text] catalysts by using density functional theory with Hubbard energy correction (DFT+U). The adsorption energy calculations indicate that even though there is a relatively higher spatial distance between the adsorbed water molecule and the [Formula: see text] surface, pristine [Formula: see text] surface is capable of anchoring [Formula: see text] molecule more strongly than the doped [Formula: see text] as well as the rutile (1 1 0) surface. Further, it was found that unlike water dissociation on crystalline [Formula: see text] surfaces, water on pristine [Formula: see text] catalyst experience the dissociation barrier. However, this barrier reduces significantly when [Formula: see text] is doped with [Formula: see text], providing an alternative route for the development of an inexpensive and more abundant catalyst for water splitting.