Porous silicon as a photocatalyst in degradation of methylene blue
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/cm2 were 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 1.0×10−5 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 min−1, 0.056 min−1, and 0.071 min−1 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.