Novel TiO2-WO3 self-ordered nanotubes used as photoanodes: Influence of Na2WO4 and H2O2 concentration during electrodeposition

Abstract

[EN] Hybrid TiO2-WO3 nanostructures has been synthesized by electrochemical anodization under controlled hydrodynamic conditions followed by electrodeposition in the presence of different contents of Na2WO4 (5, 15 and 25 mM) and H2O2 (20, 30 and 40 mM). The influence of the electrolyte used for electrodeposition on the morphology, crystalline structure and photoelectrochemical response for water splitting has been evaluated through Field Emission Electronic Microscopy, High-Resolution Transmission Electron Microscopy, Confocal Raman Spectroscopy, Grazing Incidence X Ray Diffraction, X-Ray Photoelectron Spectroscopy, Atomic Force microscopy and photocurrent versus potential measurements. Additionally, a statistical multi-factor categorical analysis was performed to determine the most significant influential parameters. Results show that hybrid TiO2-WO3 nanostructures formed by simple anodization and subsequent electrodeposition with 30 mM H2O2 and 25 mM Na2WO4 present the highest photocurrent response, 60% higher if compared to TiO2 anodized nanotubes, solving the main problems presented during the usual fabrication of heterostructures, i.e. high temperatures, pressures, number of chemicals and time.