LaF3 Doped Co3O4 Mesoporous Nanomaterials with Hierarchical Structure for Enhanced Triethylamine Gas Sensing Performances

In this study, sea-urchin-like LaF3 doped mesoporous Co3O4 (La-Co3O4) nanomaterials were obtained by the heat treatment of citric acid-assisted hydrothermally-synthesized products at 300 °C. The composition, microstructure, and morphology were investigated by different characterization methods. Structural analyses reveal that La-Co3O4 has a hierarchical structure formed by the assembly of numerous nanorods that are aggregated by countless nanosheets. We probed the sensing ability of the La-Co3O4 based sensors toward a series of volatile organic gases, such as triethylamine, xylene, and ethanol. The results indicate that the sensors exhibited excellent selectivity and responsiveness toward triethylamine, with a lower detection limit of 1.0 ppm and long-term stability at an operating temperature of 195 °C. The prominent gas sensing performance first originates from the high content of adsorbed oxygen for doping LaF3 in which the high mobility of F anions resulted in the presence of F vacancies on the surface of the composites. Additionally, the abundant porosity offered by the hierarchical structure is favorable to the adsorption of oxygen species, surface reactions, and gas diffusion during the sensing process. Doping LaF3 to the semiconductor materials may provide a potential approach for the development of novel gas sensing materials.