Description
Metal-organic frameworks (MOFs) are advantageous as sensing materials due to their distinct morphologies, high surface area, and the simplicity of calcination for removing sacrificial MOF scaffolds. Oxygen vacancies (Ovs) in metal oxides can be created efficiently by subjecting these materials to thermal annealing in an inert atmosphere. This process enhances the defect density within the oxide structure, which can significantly impact on the material's electronic and catalytic properties.
In this study, MIL-53-based Fe/Ni-MOFs nanorods (NRs) were initially synthesized via a solvothermal approach, followed by the derivation of one-dimensional (1D) Fe2O3 and Ni0.4Fe2.6O4 NRs from the MOFs after calcination in air and argon (Ar) atmospheres, respectively. Ar-annealed Ni0.4Fe2.6O4 NRs exhibit elevated Ovs concentrations and reduced dimensions compared to air-annealed NRs. Among the synthesized nanorods, the Ar-Ni0.4Fe2.6O4 NRs exhibit superior sensitivity and selectivity to amines, a low detection threshold, an extensive dynamic range, remarkable stability, and fast response/recovery times. The exceptional gas sensing performance can be ascribed to synergistic effects, structural benefits, elevated concentrations of Ovs, and the heterojunction interface, all of which significantly influence gas sensor efficacy. This paper presents a novel method for fabricating high-performance gas sensors and the creation of Ovs in metal oxides without requiring any additives.