Noble metal-modified octahedral anatase titania particles with enhanced activity for decomposition of chemical and microbiological pollutants

Abstract

Graphical abstract

Gas‐phase removal of indoor volatile organic compounds and airborne microorganisms over mono‐ and bimetal‐modified (Pt, Cu, Ag) titanium(IV) oxide nanocomposites

“…[13][14][15] Moreover, silver, copper, and zinc nanoparticles revealed biocidal properties 16,17 and metal nanoparticles such as platinum or palladium decrease charge carriers recombination rate on the surface of titanium(IV) oxide. Among commonly used semiconductors, titanium(IV) oxide is one of the most efficient photocatalyst.…”

On the Origin of Enhanced Photocatalytic Activity of Copper-Modified Titania in the Oxidative Reaction Systems

“…The main problem with utilizing Cu NPs as a "plasmonic sensitizer" is the known fact that zero-valent copper is easily oxidized and lose plasmon resonance properties gradually under ambient conditions [54][55][56]. For example, (i) although, titania modification by strong radiolytic reduction of Cu 2+ or photodeposition under anaerobic conditions resulted in formation of zero-valent copper, Cu 0 was subsequently oxidized under ambient conditions forming CuO/TiO 2 and Cu/Cu 2 O/Cu/TiO 2 , respectively [57][58][59] and (ii) even Cu NPs immersed in water were oxidized by dissolved oxygen [60]. The reported main solutions of this problem consider the necessity of preventing copper oxidation by maintaining Cu in anoxic environments [55,[61][62][63] or protecting its surface with chemical corrosion inhibitors [64], polymeric layers [47,55], and by oxide encapsulation [65].…”

“…Cu/Cu2O/Cu/TiO2, respectively [57][58][59] and (ii) even Cu NPs immersed in water were oxidized by dissolved oxygen [60]. The reported main solutions of this problem consider the necessity of preventing copper oxidation by maintaining Cu in anoxic environments [55,[61][62][63] or protecting its surface with chemical corrosion inhibitors [64], polymeric layers [47,55], and by oxide encapsulation [65].…”

“…Frequently, during preparation of copper-modified TiO2, a mixture of copper species is obtained [58,59], and such systems are named as "cascade heterojunction systems." For example, Helaili et al prepared Cu2O/TiO2, Cu/Cu2O/TiO2 and Cu/Cu2O/CuO/TiO2 heterojunctions using chemical methods, and examined their potential application as photocatalysts for oxidative reactions (Orange II as a model dye pollutant) under visible light irradiation [106].…”

“…Frequently, during preparation of copper-modified TiO 2 , a mixture of copper species is obtained [58,59] [106]. The obtained results suggested the following rules, which could govern the electrons transfer mechanism: (a) metallic Cu improved the photocatalytic activity of single semiconductor by the formation of apparent Ohmic junction enhancing the charges transfer kinetics; (b) electromotive forces developed from semiconductor/semiconductor heterojunction suppressed the effect of metallic Cu due to the formation of an apparent Schottky type junction; (c) diffusion potential developed from multiple steps electrons transfer had more impact for improving the efficiency than that developed from one step transition; and (d) heterojunction cascade obtained from monobloc of photosensitizers was more efficient than that obtained from direct mixture of the semiconductors [106].…”