Metal-Doped In2O3 Nanosphere Arrays with Enhanced Gas-Sensing Property

In2O3 and metal-doped (Ni or Ce) In2O3 mesoporous three-dimensional (3D) nanospheres arrays were synthesized via nanocasting using mesoporous silica as hard templates. Effects of Ni or Ce doping on the structure, optical and gas-sensing properties of the In2O3 nanospheres were investigated. Both the undoped and the doped In2O3 nanospheres showed single-phase structure without any impurity. The nanospheres were about 20 nm in size and they stacked closely to form rigid 3D mesoporous structure. A change in the value of optical band gap was observed upon metal doping. The room temperature photo luminescence behavior also showed some differences between pure and doped In2O3. Compared with pure In2O3 nanospheres, the metal-doped In2O3 exhibited superior response, fast recovery and good selectivity to ethanol. The enhanced gas-sensing properties might be related to the doping of metal ion and its effective contribution towards the oxygen vacancies, conductivity and crystallite size of the grains.