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 In2O3(Cu-In2O3)hollow nanofibers by electrospinning and calcination for detecting H2S.The experimental results show that the Cu doping concentration besides the operating temperature,gas concentration,and relative humidity can greatly affect the H2S sensing performance of the In2O3-based sensors.In particular,the responses of 6％Cu-In2O3 hollow nanofibers are 350.7 and 4201.5 to 50 and 100 ppm H2S at 250℃,which are over 20 and 140 times higher than those of pristine In2O3 hollow nanofibers,respectively.Moreover,the corresponding sensor exhibits excellent selectivity and good reproducibility towards H2S,and the response of 6％Cu-In2O3 is still 1.5 to 1 ppm H2S.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 In2O3 and react with H2S,resulting in significant improvement of gas sensing performance.The Cu-In2O3 hollow nanofibers can be tailored for practical application to selectively detect H2S at lower concentrations.