High-aspect ratio β-Ga₂O₃ nanorods consisting of prism-like crystals were formed using gallium oxyhydroxide and ammonia hydroxide via a hydrothermal synthesis followed by the subsequent calcination process. The formation of high-aspect ratio β-Ga₂O₃ nanorods was attributed to the oriented attachment mechanism that was present during the hydrothermal synthesis. A field-effect transistor was fabricated using the high-aspect ratio β-Ga₂O₃ nanorod, and it exhibited the typical charge transfer properties of an n-type semiconductor. This facile approach to forming high-aspect ratio nanorods without any surfactants or additives can broaden the science of β-Ga₂O₃ and expedite the integration of one-dimensional β-Ga₂O₃ into future electronics, sensors, and optoelectronics.

The photocatalytic degradation of formaldehyde, acetaldehyde, toluene, and styrene are compared using monoclinic Ga₂O₃ and anatase TiO₂ nanostructures under ultraviolet-C irradiation. These Ga₂O₃ and TiO₂ photocatalysts are characterized using a field emission scanning electron microscope, a powder X-ray diffraction system, the Brunauer–Emmett–Teller method, and a Fourier transform infrared spectrometer. The Ga₂O₃ shows a higher reaction rate constant (k, min⁻¹) than TiO₂ by a factor of 7.1 for toluene, 8.1 for styrene, 3.1 for formaldehyde, and 2.0 for acetaldehyde. The results demonstrate that the photocatalytic activity ratio of the Ga₂O₃ over the TiO₂ becomes more prominent toward the aromatic compounds compared with the nonaromatic compounds. Highly energetic photo-generated carriers on the conduction/valence band-edge of the Ga₂O₃, in comparison with that of the TiO₂, result in superior photocatalytic activity, in particular on aromatic volatile organic compounds (VOCs) with a high bond dissociation energy.

Hybrid nanostructures made of gallium oxide (Ga₂O₃) and reduced graphene oxide (rGO) are synthesized using a facile hydrothermal process method, where the Ga₂O₃ nanostructures are well dispersed on the rGO surface. The formed Ga₂O₃-rGO hybrids are characterized via Field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), a diffuse reflectance Ultraviolet-visible-near infrared (UV-Vis-NIR) spectrophotometer, Brunauer–Emmett–Teller (BET), and photoluminescence (PL). Gas chromatography mass spectrometry (GC-MS) was used for analyzing volatile organic compounds (VOCs). The photocatalytic activity of the hybrid nanostructures is evaluated via the degradation of the 2-butanone, representing the VOCs under 254-nm radiation in the atmosphere. That activity is then compared to that of the Ga₂O₃ and commercial TiO₂-P25. The Ga₂O₃-rGO hybrid shows enhanced photocatalytic degradation of 2-butanone compared to Ga₂O₃ and TiO₂-P25, which is attributed to the enhanced specific surface area. The results indicate that the Ga₂O₃-rGO hybrid could be a promising method of enhancing photocatalytic activity and thereby effectively degrading VOCs, including the 2-butanone.

β-Ga₂O₃ has attracted considerable attention as an alternative photocatalyst to replace conventional TiO₂ under ultraviolet-C irradiation due to its high reduction and oxidation potential. In this study, to enhance the photocatalytic activity of β-Ga₂O₃, nanofibers are formed via the electrospinning method, and Si atoms are subsequently doped. As the Si concentration in the β-Ga₂O₃ nanofiber increases, the optical bandgap of the β-Ga₂O₃ nanofibers continuously decreases from 4.5 eV (intrinsic) to 4.0 eV for the Si-doped (2.4 at. %) β-Ga₂O₃ nanofibers, and accordingly, the photocatalytic activity of the β-Ga₂O₃ nanofibers is enhanced. This higher photocatalytic performance with Si doping is attributed to the increased doping-induced carriers in the conduction band edges. This differs from the traditional mechanism in which the doping-induced defect sites in the bandgap enhance separation and inhibit the recombination of photon-generated carriers.