An investigation of nanostructured rutile and anatase plates for improving thephotosplitting of water

Abstract

Developing new semiconductor materials for improving photocatalytic reactivity isimportant for solving the challenging environmental and energy problems we are facingtoday. This work focuses on increasing the quantum efficiency in titania photocatalysts forphotocatalytic (oxidation of acetaldehyde) and photosynthetic (photosplitting of water)reactions by synthesizing pure phase rutile and anatase nanostructures with well definedmorphologies and investigating their photocatalytic performance compared to a commercialtitania photocatalyst (Degussa P25). Nanostructured anatase is dominated by{100} surfaces with a small amount of {101} surfaces, whereas the rutile nanoplatesconsist of nanorods dominated by {110} and {111} crystal surfaces. In accordance withthe signals from electron spin resonance (ESR) spectra, both nanostructuredanatase and rutile phases have high photocatalytic activity for photosplittingof water compared to P25 titania. The anatase phase shows a high activity forphotocatalytic oxidation (PCO) of acetaldehyde whereas the rutile phase shows a loweractivity. The results of these experiments basically agree with previously publishedworks that reported that the oxidation and reduction sites on rutile particlesare on the {011} and {110} faces respectively, and on {001} and {011} faces respectivelyfor anatase particles. The results have important implications for enhancing thephotocatalytic activity of titania for environmental remediation, increasing the quantumefficiency in photo-voltaic (PV) solar cells and other photo-assisted processes.