TiO2/Si nanowires hybrid system for efficient photocatalytic degradation of organic dye

Herein, titanium dioxide (TiO2)-coated vertically aligned silicon nanowires (SiNWs/TiO2) were fabricated and evaluated for photocatalytic degradation of organic dyes. Aligned SiNWs arrays were prepared by facile metal-assisted chemical-etching process with varying the etching time that was followed by TiO2 nanoparticles coating using sputtering technique. The TiO2 film crystallized in pure anatase phase with an average crystalline size of 50 nm, as was elucidated with X-ray diffraction studies. SEM analysis showed nanowires with varying lengths from 2.5 to 13.5 mu m and confirmed the homogenous surface decoration with TiO2. The homogeneous distribution of TiO2 nanoparticles on nanowires was co-evidenced with Energy-Dispersive X-ray spectroscopy (EDX) and Raman spectra analysis. The developed SiNWs/TiO2 was exploited for photocatalytic degradation of methylene blue; the role of hydrogen peroxide was also elucidated. The highest photocatalytic efficiency of 96% was achieved for SiNWs/TiO2 with optimum nanowire length of 3.5 mu m. The developed photocatalyst was found to be almost stable even after 190 days (similar to 5 months) and could be used as reusable and easily removable photocatalysts. The current study highlighted the SiNWs/TiO2/H2O2 system as excellent candidate for water remediation applications.

Automated summary

In this study, vertically aligned silicon nanowires coated with titanium dioxide (SiNWs/TiO2) were successfully fabricated for the photocatalytic degradation of organic dyes. The TiO2 film exhibited pure anatase phase crystallization, with an average crystalline size of 50 nm, as confirmed by X-ray diffraction analysis. SEM, EDX, and Raman spectra analysis further supported the homogeneous distribution of TiO2 nanoparticles on the nanowires. The developed SiNWs/TiO2 showed a high photocatalytic efficiency of 96% at an optimum nanowire length of 3.5 µm, and demonstrated stability for up to 190 days, making it a promising candidate for water remediation applications.