Mechanism in Nb doped titania oxygen gas sensor

Doping in titania (TiO2) with pentavalent Nb+5 metal ion has shown significant enhancement in the sensitivity which is about 65 times higher than the undoped material at lower operating temperatures. The higher sensitivity and the shorter response time has been observed with low concentration of Nb doping i.e. 0.05, 0.2 and 0.4 wt.% Nb at 400 degrees C. The electronic interaction of TiO2 with Nb metal ion has been investigated using x-ray photoelectron spectroscopy (XPS). The maximum shift in binding energy (B.E.) of Ti 2p peak has been observed with 0.2 wt.% Nb indicating maximum interaction at this Nb concentration. The spin-orbit (s-o) splitting of Ti 2p peak indicates the change in the oxidation state of Ti. (C) 1998 Elsevier Science S.A. All rights reserved.