Effectively Improved CH<sub>4</sub> Sensing Performance of In<sub>2</sub>O<sub>3</sub> Porous Hollow Nanospheres by Doping with Cd
Xiaohua Wang, Yanwei Li, Xinhui Jin, Guang Sun, Jianliang Cao, Yan Wang
Abstract
Recently, due to the promising application of metal oxide semiconductors in high-performance methane (CH 4 ) sensors, more attention has been paid to the development of feasible strategies for improving CH 4 sensing performance. Herein, we present a strategy of cadmium (Cd) doping to improve the CH 4 sensing property of In 2 O 3 porous hollow nanospheres (PHNSs). The Cd-doped In 2 O 3 PHNSs were prepared via an impregnation–calcination approach with self-made carbon nanospheres as a hard template. The samples were characterized by various techniques to evaluate their structure, morphology, surface state, composition, and band gap. When applied as a sensitive material in the CH 4 sensor, the Cd-doped In 2 O 3 PHNSs, compared with bare In 2 O 3 PHNSs, showed some significant improvements in performance, especially a reduced operating temperature (200 °C vs 300 °C), an enhanced response (9.5 vs 2.5 for 500 ppm of CH 4 ), a faster response speed (16 s vs 276 s), and better selectivity. In addition, the Cd-doped In 2 O 3 sensor can also maintain a commendable long-term stability, and the range of its response amplitude within 30 days is only 6.3%. The sensitization effects of the Cd dopant on the In 2 O 3 PHNSs are discussed.