Excellent quality amorphous aluminum oxide (AlO x) thin films have been obtained by atmospheric pressure solution-processed mist chemical vapor deposition (mist-CVD) technique at 400°C using water-free solvent. Xray fluorescence investigations verified the formation of AlO x film by the mist-CVD. X-ray diffraction, X-ray photoelectron spectroscopy, ellipsometry and X-ray reflectivity analyses revealed that the synthesized amorphous AlO x films have bandgap of 6.5 eV, refractive index of 1.64 and mass density of 2.78 g/cm 3. These values are comparable to those reported for high-quality amorphous Al 2 O 3 thin films deposited by atomic layer deposition method.

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Aluminum titanium oxide (Al1–xTixOy, an alloy of Al2O3 and TiO2), an attractive high-κ dielectric material, was synthesized by mist chemical vapor deposition, utilizing Al2O3 and TiO2 precursors. X-ray diffraction investigations revealed that the Al1–xTixOy (0 < x < 0.72) films deposited at 400 °C have an amorphous-phase structure. It was found that the bandgap of the Al1–xTixOy films decreases with increasing Ti composition. Moreover, the obtained refractive index, mass density and bandgap of Al2O3 and TiO2 films are all comparable to those reported for high-quality Al2O3 and TiO2 films deposited by atomic layer deposition.

The replacement of precious metals (Rh, Pd, and Pt) in three-way catalysts with inexpensive and earth-abundant metal alternatives is an ongoing challenge. In this research, we examined various quaternary metal catalysts by selecting from six 3d transition metals, i.e., Cr, Mn, Fe, Co, Ni, and Cu, equimolar amounts (0.1 mol each), which were prepared on the Al 2 O 3 support (1 mol Al) using H 2 reduction treatment at 900 °C. Among 15 combinations, the best catalytic performance was achieved by the CrFeNiCu system. Light-off of NO−CO−C 3 H 6 −O 2 −H 2 O mixtures proceeded at the lowest temperature of ≤200 °C for CO, ≤300 °C for C 3 H 6 , and ≤400 °C for NO when the molar fraction of Cr in Cr x Fe 0.1 Ni 0.1 Cu 0.1 was around x = 0.1. The activity for CO/C 3 H 6 oxidation was superior to that of reference Pt/Al 2 O 3 catalysts but was less active for NO reduction. The structural analysis using scanning transmission electron microscopy and X-ray absorption spectroscopy showed that the as-prepared catalyst consisted of FeNiCu alloy nanoparticles dispersed on the Cr 2 O 3 −Al 2 O 3 support. However, the structural change occurred under a catalytic reaction atmosphere, i.e., producing NiCu alloy nanoparticles dispersed on a NiFe 2 O 4 moiety and Cr 2 O 3 −Al 2 O 3 support. The oxidation of CO/C 3 H 6 can be significantly enhanced in the presence of Cr oxide, resulting in a faster decrease in O 2 concentration and thus regenerating the NiCu metallic surface, which is active for NO reduction to N 2 .

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