The pure porous ZnMn2O4 microspheres were prepared by a one-step hydrothermal technique with different concentrations of Urea (ZU). Various techniques including XRD, FESEM, PL, UV–Vis, FT-IR and EDS were used to study the structural and morphological properties of the obtained samples. The results show that the obtained samples have high purity and by changing the concentration of urea, the microspheres have rough surfaces, which is useful for gas sensing properties. Then, the gas sensor properties of the fabricated sensor layers were investigated for isopropanol vapor with different concentrations at different working temperatures. Gas sensing results confirm that the ZU films exhibit a high response of 5.54 for ZU3 (500 ppm isopropanol), a very fast response time of 2.5 s for ZU2 (400 ppm) and ZU3 (300 ppm), and excellent selectivity with a difference of approximately 107 % compared to DMF at a relatively low temperature. In addition, the gas sensing mechanism was also thoroughly discussed.
