Facile Fabrication of ZnO-ZnFe₂O₄ Hollow Nanostructure by a One-Needle Syringe Electrospinning Method for a High-Selective H₂S Gas Sensor

Herein, a facile fabrication process of ZnO-ZnFe2O4 hollow nanofibers through one-needle syringe electrospinning and the following calcination process is presented. The various compositions of the ZnO-ZnFe2O4 nanofibers are simply created by controlling the metal precursor ratios of Zn and Fe. Moreover, the different diffusion rates of the metal oxides and metal precursors generate a hollow nanostructure during calcination. The hollow structure of the ZnO-ZnFe2O4 enables an enlarged surface area and increased gas sensing sites. In addition, the interface of ZnO and ZnFe2O4 forms a p-n junction to improve gas response and to lower operation temperature. The optimized ZnO-ZnFe2O4 has shown good H2S gas sensing properties of 84.5 (S = R-a/R-g) at 10 ppm at 250 degrees C with excellent selectivity. This study shows the good potential of p-n junction ZnO-ZnFe2O4 on H2S detection and affords a promising sensor design for a high-performance gas sensor.