title: Laser irradiation in water for the novel, scalable synthesis of black TiOxphotocatalyst for environmental remediation.
abstract: Since 1970, TiO2photocatalysis has been considered a possible alternative for sustainable water treatment. This is due to its material stability, abundance, nontoxicity and high activity. Unfortunately, its wide band gap (≈3.2 eV) in the UV portion of the spectrum makes it inefficient under solar illumination. Recently, so-called "black TiO2" has been proposed as a candidate to overcome this issue. However, typical synthesis routes require high hydrogen pressure and long annealing treatments. In this work, we present an industrially scalable synthesis of TiO2-based material based on laser irradiation. The resulting black TiOxshows a high activity and adsorbs visible radiation, overcoming the main concerns related to the use of TiO2under solar irradiation. We employed a commercial high repetition rate green laser in order to synthesize a black TiOxlayer and we demonstrate the scalability of the present methodology. The photocatalyst is composed of a nanostructured titanate film (TiOx) synthetized on a titanium foil, directly back-contacted to a layer of Pt nanoparticles (PtNps) deposited on the rear side of the same foil. The result is a monolithic photochemical diode with a stacked, layered structure (TiOx/Ti/PtNps). The resulting high photo-efficiency is ascribed to both the scavenging of electrons by Pt nanoparticles and the presence of trap surface states for holes in an amorphous hydrogenated TiOxlayer.
authors.affiliation: CNR-IMM, via S. Sofia 64, 95123 Catania, Italy.
authors.forename: Massimo
authors.initials: M
authors.lastname: Zimbone
authors.affiliation: CNR-IMM, via S. Sofia 64, 95123 Catania, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Cacciato
authors.affiliation: Grupo de Aplicaciones Industriales de los Láseres, Departamento de Física Aplicada, E.T.S. Ingenieros Industriales de Vigo, Rúa Maxwell, s/n, Campus Universitario, 36310 Vigo, Spain.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Boutinguiza
authors.affiliation: CNR-IMM, via S. Sofia 64, 95123 Catania, Italy.
authors.forename: Vittorio
authors.initials: V
authors.lastname: Privitera
authors.affiliation: CNR-IMM, via S. Sofia 64, 95123 Catania, Italy; Dipartimento di Fisica e Astronomia, Università di Catania, via S. Sofia 64, 95123 Catania, Italy.
authors.forename: Maria Grazia
authors.initials: MG
authors.lastname: Grimaldi
keywords: TiOx; black titania; laser irradiation in water; photocatalysis; water treatment