A forest of SiO2 nanowires covered by a TiO2 thin film for an efficient photocatalytic water treatment

Abstract

We propose a highly disordered and randomly oriented array (forest) of SiO₂ nanowires (NWs) coated by a thin film of TiO₂ as a performing photocatalytic material for water treatment applications. The SiO₂ NWs with a length of tens of microns were obtained via thermal oxidation of Si NWs, grown by plasma enhanced chemical vapour deposition (PECVD), and covered by a nanometric TiO₂ film deposited by atomic layer deposition (ALD). The remarkable photocatalytic performance of the TiO₂/SiO₂ NWs was demonstrated by the degradation of methylene blue and phenols in water. The enhanced photocatalytic activity in the overlaying TiO₂ film is attributed to the synergetic effect of the morphology and optical properties of the SiO₂ NWs. The fabrication methods based on the well-established Si technology make the proposed materials a promising strategy for water treatment.