Photoelectrochemical Analysis of Anion-Doped TiO[sub 2] Colloidal and Powder Thin-Film Electrodes

Abstract

The photoelectrochemical characteristics of anion-doped TiO2TiO2 powder and colloidal electrodes were investigated under UV and visible illumination. The solar absorption of TiO2TiO2 was improved by synthesizing reduced forms of TiO2TiO2 using anions of the main group elements (C, N, and P) to substitute for oxygen in the titania lattice. Analytical methods, including scanning electron microscopy, X-ray diffraction, elemental analysis, Raman, and UV–visible spectroscopy were employed to characterize these materials. The photoactivity of the electrodes was evaluated using a three-electrode configuration quartz photoelectrochemical cell using simulated solar irradiance. All anion-doped TiO2TiO2 electrodes investigated, specifically C-, N-, and P-doped, increased the visible absorption (λ400nm)(λ400nm) of n- TiO2TiO2 , leading to higher photoactivity under solar light. The addition of methanol to the electrolyte reduced the rapid charge recombination and hence enhanced the photocurrents. Although the efficiency is not yet comparable to single-crystal n- TiO2TiO2 , optimization of the parameters studied here showed that significant increases in photoactivity could be achieved over the native TiO2TiO2 powder.