Well dispersed crystallites
were filled in the nanotubes after decoration. Incorporated TiO2
nanoparticles can be found to increase the surface area and the
thickness of space charge layer, although utilization of light is
reduced and charge transfer resistance is increased. With the help
of external bias, beneficial aspects of decoration on TiO2 nanotube
arrays play the leading role. Enhanced photoelectrocatalytic performances
for the degradation of target dyes such as MB, RhB, MeO
and K-2G on the decorated TiO2 nanotube arrays are observed.
Moreover, anodic bias can improve the degradation rates of dyes
with anionic groups more than those with cationic groups. The
results presented in this work indicate the modification of TiO2
nanotube arrays by TiO2 particles supplies a promising strategy
to balance the high efficiency of charge separation and the
large surface area of TiO2 nanotube arrays in photoelectrocatalytic
process.