Porous Si/TiO2 nanowire photoanode for photoelectric catalysis under simulated solar light irradiation

Porous Si/TiO2 nanowire photoanodes were prepared by a combination of hydrothermal synthesis and metal‐assisted chemical etching. Characterization of samples was conducted using scanning electron microscopy and X‐ray diffraction, the results showing that a porous Si/TiO2 heterojunction structure was synthesized. Diffuse reflection spectra show that the porous Si/TiO2 nanowire photoanodes have a strong absorption. Photocurrent measurement shows that the photocurrent of the porous Si/TiO2 nanowire photoanodes at 6 h is higher than that of others in the measuring region. The photoelectric catalysis (PEC) activities of porous Si/TiO2 nanowire photoanodes were evaluated in degradation experiments of methylene blue under simulated solar light irradiation, and the sample at 6 h shows the highest PEC activity. Meanwhile, the PEC activity of the porous Si/TiO2 nanowire photoanode is higher than that of the single direct photocatalysis process or electric catalysis. The mechanism of the PEC of the porous Si/TiO2 nanowire photoanodes has been explained. The photoelectric catalysis (PEC) of porous Si/TiO2 nanowires photoanodes shows the greater activities relative to the directly photo catalysis (DP) and the electric catalysis (EC). It's believe that the combined effect of the light irradiation and the bias potential leads to the highest catalysis activity.