Fluoride-tuned synthesis of hematite micro-spheres coated with ultrafine particles for smart detection of acetone

In this study, hematite (α-Fe2O3) micro-spheres coated with ultrafine particles (MSUPs) have been obtained for sensitive acetone sensors via first hydrothermal process with NH4F as the morphological regulator and then annealing of akaganeite. The role of fluoride ion concentration in precursor solution on the morphology has been demonstrated, and the corresponding reaction mechanism was discussed as well. The α-Fe2O3 MSUPs with 0.45 M NH4F (F0.5) in the precursor solution showed the highest response towards acetone compared to other α-Fe2O3 samples. Our α-Fe2O3 MSUPs sensors have potential in sensitive acetone detection.