Porous silicon as a photocatalyst in degradation of methylene blue

  • Vladimir Sarmiento Materials Science and Engineering Program, University of the Philippines Diliman
  • Arven Cafe National Institute of Physics, University of the Philippines Diliman
  • Catherine Tugado Materials Science and Engineering Program, University of the Philippines Diliman
  • Joybelle Lopez Materials Science and Engineering Program, University of the Philippines Diliman
  • Efren Suratos, Jr. Materials Science and Engineering Program, University of the Philippines Diliman
  • Arnel Salvador National Institute of Physics, University of the Philippines Diliman
  • Elmer Estacio National Institute of Physics, University of the Philippines Diliman
  • Armando Somintac National Institute of Physics, University of the Philippines Diliman
Keywords: Fabrication of porous materials, Photodegradation, Optical properties of nanoporous materials

Abstract

The photocatalytic degradation of methylene blue (MB) using porous silicon (PSi) as catalysts was tested. PSi samples were synthesized via electrochemical etching of highly doped p-type silicon. Varying current densities of 3mA/cm2, 10mA/cm2, and 30mA/cmwere applied having calculated porosities of 59%, 67% and 74%, respectively.  Porosity increases as the applied anodic current also increases. Using improvised UV photoreactor setup, the degradation efficiency of 1.0×105 M concentration of MB dye was measured for different PSi samples. Synthesized PSi samples with current densities of 3 mA/cm2, 10 mA/cm2 and 30 mA/cm2 have obtained degradation rates of 0.051 min1, 0.056 min1, and 0.071 min1 respectively. Results showed that the PSi sample having the lowest porosity have 49% degradation efficiency after 1 hour of UV irradiation which is highest among the samples.  Increasing porosity resulted to decrease in degradation efficiency due to the increased surface area-to-volume ratio.

Published
2017-06-07
Section
Poster Session A (Experimental Materials Science and Photonics)