Preparation of High-Performance 2-Butanone Gas Sensors Using Ag Decorated on the Surface of Co3O4 Nanocomposite With Defects Induced by Fe Doping

In this work, we fabricated Co3O4-based nanocomposites (Ag at Fe-Co3O4) by a two-step operation of elemental Fe doping to induce defects and surface modification with Ag nanoparticles (AgNPs) and investigated their utility in 2-butanone gas sensing. The Ag at Fe-Co3O4 nanocomposites were characterized by scanning electron microscopy (SEM), Brunauer Emmet-Teller measurements (BETs), transmission electron microscopy (TEM), high resolution TEM (HRTEM), energy dispersive spectroscopy (EDS) analysis, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The Ag at Fe-Co3O4 sensor improved by two sensitization methods has good performance in detecting 2-butanone gas. For a concentration of 100 ppm of 2-butanone, excellent response values of 370 were obtained at a low operating temperature of 150 °C, which were ~3.7 and ~28.5 times higher than those of the Fe-Co3O4 (101) and pure Co3O4 (13) sensors, respectively. In addition, the Ag at Fe-Co3O4 sensor exhibited excellent selectivity and outstanding reproducibility. For the excellent performance of the sensor, we have explored the material morphology, lattice defects, noble metal catalysis, and electron sensitization to comprehensively investigate the sensor operating principle and sensitization mechanism of Co3O4-based 2-butanone gas sensor.