CO gas-sensing properties and DFT investigation of pure and Co-modified MoO3 nanostructures: effect of solvent composition, deposition time, and cobalt concentration

Resumen In this study, thin films of pure and cobalt-modified molybdenum oxide (MoO3) were deposited using nebulizing spray pyrolysis (NSP). The research delves into the influence of deposition times (30 and 60 mins), solvents (H2O and H2O/HCl), and cobalt modification (3 %wt and 6 %wt) on the structural, morphological, and electrical properties of the thin films. XRD and FTIR were employed for structural analysis, while SEM and AFM were used to examine morphology and topography. X-ray analysis revealed the predominantly amorphous state of most of the films, and FTIR allowed visualization of different functional groups of MoO3 based on deposition time and dopant concentration. In addition, SEM revealed an increase in grain size with longer deposition times, and AFM demonstrates that the cobalt-modified films exhibited higher roughness than pure molybdenum oxide films. Pure MoO3 films using H2O as a solvent showed the highest gas-sensing response to CO at 76%, followed by films modified with 6 wt% Co, which exhibited a sensing response of 66%. The cobalt-modified films exhibited a lower sensitivity response than pure films, attributed to the formation of cobalt oxide. The CO adsorption properties on multiple MoO3 structures and Co3O4 have been optimized and analyzed using density functional theory (DFT). The best absorption energy of CO onto the different phases of MoO3 and Co3O4 has been reported to contrast it with the experimental results. This study marks the first report on cobalt-modified molybdenum oxide films, combining theoretical and practical exploration for CO detection through spray pyrolysis and DFT.

Autores. María de la Luz Olvera Amador
Revista. J Mater Sci: Mater Electron 
https://doi.org/10.1007/s10854-024-12501-y