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The effect of growth parameters on photo-catalytic performance of the MAO-synthesized TiO2 nano-porous layers
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The effect of growth parameters on photo-catalytic performance of the MAO-synthesized TiO2 nano-porous layers

Bayati, M. R

The effect of growth parameters on photo-catalytic performance of the MAO-synthesized TiO2 nano-porous layers

Bayati, M. R ; Sharif University of Technology | 2010

751 Viewed
  1. Type of Document: Article
  2. DOI: 10.1016/j.matchemphys.2009.12.005
  3. Publisher: 2010
  4. Abstract:
  5. In this research, the effect of applied voltage and electrolyte concentration on structure, chemical composition, optical properties, and especially photo-catalytic activity of the TiO2 layers containing micro/nano-sized pores are discussed. TiO2 layers were synthesized by micro arc oxidation (MAO) process using different electrolyte concentrations and applied voltages. Surface structure of the layers was studied by scanning electron microscope (SEM); furthermore, energy dispersive spectrophotometry (EDS), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) techniques were employed to determine phase structure and chemical composition of the layers. Photo-activity of the layers was also examined by measuring the decomposition rate of methylene blue on their surfaces. Band gap energy of the grown layers was also measured by a UV-vis spectrophotometer. It was found that there is a critical voltage at which electrical sparks begin to appear on the anode surface due to applying voltages higher than breakdown voltage of the surface gas layer. The critical voltage which was responsible for formation of structural pores decreased at higher concentrations of electrolyte. Meanwhile, surface pore size increased at higher applied voltages, or alternatively using electrolytes with higher concentrations. The layers contained the anatase and the rutile phases whose fractions varied with the synthesis parameters. It was also revealed that the band gap energy of the grown layers decreased with the applied voltage and electrolyte concentration. Moreover, the photo-catalytic performance of the layers synthesized at medium applied voltages was higher than that of the layers produced at lower or higher voltages. More than 90% of methylene blue solution was decomposed after 160 min UV irradiation on the layers produced in an electrolyte with a concentration of 10 g l-1
  6. Keywords:
  7. Nano structures ; Porous materials ; Anode surfaces ; Applied voltages ; Band gap energy ; Breakdown voltage ; Chemical compositions ; Chemical synthesis ; Concentration of ; Critical voltages ; Decomposition rate ; Electrolyte concentration ; Energy dispersive ; Gas layers ; Growth parameters ; Methylene Blue ; Methylene blue solution ; Microarc oxidation ; Nano-porous ; Photo-catalytic ; Photocatalytic activities ; Rutile phasis ; Scanning electron microscopes ; Surface pores ; Synthesis parameters ; TiO ; UV irradiation ; UV-Vis spectrophotometers ; Catalyst activity ; Cavity resonators ; Concentration (process) ; Electrolysis ; Electrolytes ; Energy gap ; Nanostructures ; Optical properties ; Oxidation ; Oxide minerals ; Porous materials ; Scanning electron microscopy ; Spectrophotometry ; Surface structure ; Titanium ; Titanium dioxide ; X ray diffraction ; X ray photoelectron spectroscopy ; Synthesis (chemical)
  8. Source: Materials Chemistry and Physics ; Volume 120, Issue 2-3 , 2010 , Pages 582-589 ; 02540584 (ISSN)
  9. URL: http://www.sciencedirect.com/science/article/pii/S0254058409007512