Aliovalent Fe(iii)-doped NiO microspheres for enhanced butanol gas sensing properties.

Fe-Doped NiO multi-shelled microspheres have been synthesized via a facile hydrothermal reaction. Various characterization techniques were introduced to investigate the structure and morphology of the as-prepared Fe-doped NiO multi-shelled microspheres. SEM and TEM observations showed that NiO microspheres are about 500 nm in diameter and with three shells. The Fe-doped NiO multi-shelled microspheres were investigated systematically as gas sensing materials for chemiresistive semiconductor-based gas sensors. The results showed that the 1.92 at% Fe-doped NiO (1.92Fe-NiO) multi-shelled microspheres exhibited enhanced gas sensing performance compared to the pure NiO multi-shelled microspheres. The gas response of 1.92Fe-NiO multi-shelled microspheres to 100 ppm butanol was 45.1 at 140 °C, which revealed a remarkable improvement over the pure NiO multi-shelled microspheres (6.80). The increased response of 1.92Fe-NiO multi-shelled microspheres may be attributed to the incorporation of Fe ions into NiO nanocrystals, which adjusted the carrier concentration and caused an increase in the oxygen species on the adsorbed surface. Therefore, the Fe-doped NiO multi-shelled microspheres should be a promising material for high performance butanol gas sensors.