Electrospun Cu-doped In2O3 hollow nanofibers with enhanced H2S gas sensing performance
Yu Zhang, Shuai Han, Mingyuan Wang, Siwei Liu, Guiwu Liu, Xianfeng Meng, Ziwei Xu, Mingsong Wang, Guanjun Qiao
Abstract
Abstract One-dimensional nanofibers can be transformed into hollow structures with larger specific surface area, which contributes to the enhancement of gas adsorption. We firstly fabricated Cu-doped In 2 O 3 (Cu-In 2 O 3 ) hollow nanofibers by electrospinning and calcination for detecting H 2 S. The experimental results show that the Cu doping concentration besides the operating temperature, gas concentration, and relative humidity can greatly affect the H 2 S sensing performance of the In 2 O 3 -based sensors. In particular, the responses of 6%Cu-In 2 O 3 hollow nanofibers are 350.7 and 4201.5 to 50 and 100 ppm H 2 S at 250 °C, which are over 20 and 140 times higher than those of pristine In 2 O 3 hollow nanofibers, respectively. Moreover, the corresponding sensor exhibits excellent selectivity and good reproducibility towards H 2 S, and the response of 6%Cu-In 2 O 3 is still 1.5 to 1 ppm H 2 S. Finally, the gas sensing mechanism of Cu-In2O3 hollow nanofibers is thoroughly discussed, along with the assistance of first-principles calculations. Both the formation of hollow structure and Cu doping contribute to provide more active sites, and meanwhile a little CuO can form p–n heterojunctions with In 2 O 3 and react with H 2 S, resulting in significant improvement of gas sensing performance. The Cu-In 2 O 3 hollow nanofibers can be tailored for practical application to selectively detect H 2 S at lower concentrations.