Beilstein Journal of Nanotechnology (Jan 2017)

Laser irradiation in water for the novel, scalable synthesis of black TiOx photocatalyst for environmental remediation

  • Massimo Zimbone,
  • Giuseppe Cacciato,
  • Mohamed Boutinguiza,
  • Vittorio Privitera,
  • Maria Grazia Grimaldi

DOI
https://doi.org/10.3762/bjnano.8.21
Journal volume & issue
Vol. 8, no. 1
pp. 196 – 202

Abstract

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Since 1970, TiO2 photocatalysis 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 TiOx shows a high activity and adsorbs visible radiation, overcoming the main concerns related to the use of TiO2 under solar irradiation. We employed a commercial high repetition rate green laser in order to synthesize a black TiOx layer 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 TiOx layer.

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