Production of MFe2O4 (M = Zn, Ni, Cu, Co and Mn) multiple cavities microspheres with salt template to assemble a high-performance acetone gas sensor

Abstract

In this study, a one-step chemical vapor deposition (CVD) method was used, utilizing template NaCl and dextrin as the porogen and structural support. The synthesized spinel MFe2O4 (M = Zn, Ni, Cu, Co and Mn) microspheres with multiple cavities structure were applied to the acetone gas sensor detection. Through the characterization of the sensitive materials, the average pore diameter of the microspheres was about 60 nm. Compare with other metal cations, when M = Zn or Ni, the MFe2O4 samples revealed the super gas sensitivity at working temperatures of 250 °C and 175 °C, and the response values to 100 ppm acetone were 25 and 24.3, respectively. In addition, they also exhibited excellent selectivity and long-term stability to acetone. The excellent gas sensitivity of ZnFe2O4 and NiFe2O4 could be attributed to the replacement of Fe with Zn and Ni ions to obtain a higher Fe3+/Fe2+ atomic ratio, thereby increasing the content of adsorbed oxygen. In summary, the gas sensing performance of spinel MFe2O4 oxide had been systematically studied by replacing Fe with other transition metals. The iron-containing spinel oxides are expected to be promising sensing material for gas sensors due to their rich elements and excellent activity.