Preparation and bifunctional gas sensing properties of porous In2O3-CeO2 binary oxide nanotubes.
The porous binary In(2)O(3)-CeO(2) oxides nanotubes (NTs) in cubic phase were first fabricated by electrospinning (ESP) method and characterized by SEM, TEM, XRD, XPS and UV-vis absorption techniques. By adjusting the In(2)O(3) and CeO(2) molar ratio, the out diameters and wall thicknesses of the final composites were tuned ranging of 90-180 nm and 15-9 nm, respectively. The band gap of the binary oxides gradually decreases, and the ratio of Ce(3+) to Ce(4+) increases with the increase of CeO(2), implying that surface oxygen vacancies gradually increase. The gas sensing test reveals that when the content of CeO(2) is appropriate, the as fabricated In(2)O(3)-CeO(2) NTs could be bifunctional gas sensors to detect H(2)S at low temperature(25-110 °C) while acetone at relative high temperature (300 °C). The In(75)Ce(25) NTs sensor is an optimum one, which exhibits the highest response of 498 to H(2)S at 80 °C and the highest response of 30 to acetone at 300 °C. In contrast to the pure In(2)O(3) sensor, the response and recovery times, as well as the sensing reaction barrier height, for In(75)Ce(25) both degrade considerably. The above temperature-dependent sensing properties were attributed to two different gas sensing mechanisms, sulfuration at low temperature and adsorption at high temperature.
State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun, 130012, People's Republic of China.
Lin
L
Xu
Hongwei
H
Song
Biao
B
Dong
Yu
Y
Wang
Jiansheng
J
Chen
Xue
X
Bai