EFFECTS OF SINTERING ON THE PHOTOELECTROCHEMICAL PROPERTIES OF NB-DOPED TIO2 ELECTRODES

Several TiO2 pellets, doped with 0.05-0.9 mol% Nb2O5, were prepared for the photoelectrochemical study. The effects of sintering temperature, sintering time, and doping concentration were investigated. The resulting structures were examined by scanning electron microscopy. Among these specimens, the TiO2 electrode O2/0.05% Nb2O5 had the best performance and its photocurrent density was higher than those reported in the literature. The optimum heat treatment was 1350-degrees-C for 10 h. In general, increasing the sintering temperature or sintering temperature or sintering time would increase the photo response, presumably due to more complete diffusion of Nb or larger grain size. However, higher temperature or prolonged sintering might also cause the segregation of Nb on the grain boundaries, thereby deteriorating the photoelectrochemical properties.