Impact of Nb doping on gas-sensing performance of TiO2 thick-film sensors

Using a simple hydrothermal method, the pristine and Nb doped TiO2 is prepared, and their microstructures and gas-sensing responses to the harmful volatile organic compounds are investigated with a special focus on the impact of Nb additive. We find that the gas response of TiO2 is enhanced significantly by doping Nb, which is understood in theory upon proposed adsorption models. Combining experimental measurements with first-principles calculations, the working mechanism underlying such improvement in gas-sensing functions by the Nb additive is discussed.