Preparation of MnO_2-loaded Co₃O₄ to enhance acetone sensing properties

Heterojunction-based gas sensors have drawn significant interest due to their more sensitive nature as compared to tetrahedral metal oxide. However, developing homogenous and durable heterojunctions by conventional synthesis techniques is challenging. This work
intended to generate MnO 2-loaded Co 3 O 4 composites under specific conditions using the mechanochemical synthesis technique. The structural, morphological, optical, and gas-sensing properties of pure MnO 2, pure Co 3 O 4, and 0.5 wt. % MnO 2-loaded 0.5 wt.% Co 3 O 4 composite were investigated. X-ray diffraction (XRD) examination revealed that the self-synthesized samples were crystalline and had no secondary phases. Scanning electron microscopy (SEM) of selected samples revealed a high degree of agglomeration. Moreover, research on gas sensing has demonstrated that oxygen vacancies preferentially occur close to Co- ions, which reduces the Co-ion charge, and a neutral structure is formed as a result. Due to MnO 2's influence corroborating the local Co-to-Mn charge transfer mechanism, a response and recovery time of 79 and 273sec was observed at 25ppm acetone and at 200 o C. It was concluded from the data that constructing heterojunctions would be an effective approach to enhance the prepared gas sensor's sensitivity. Furthermore, the present research offers a simple, versatile, and adaptable method for synthesizing heterojunctions with excellent structural uniformity for use in a variety of industrial applications.