Exploring the Synergistic Interplay of Optical, Morphological, and Catalytic Features in Ga-Doped ZnO Nanoparticles: Harnessing Their Potential for Photocatalytic Dye Degradation under UV-Green Light Irradiation

This work explores the synthesis and characterization of undoped ZnO, Ga-doped ZnO (Ga:ZnO), and γ-Ga₂O₃ quasi-spherical nanoparticles and their catalytic activity in Rhodamine B photodegradation under UV-visible light exposure. Gallium dopant incorporation into Ga:ZnO was confirmed by inductively coupled plasma optical emission spectroscopy (ICP-OES), Fourier transform infrared (FT-IR), and powder X-ray diffraction (XRD), maintaining the hexagonal wurtzite structure with an additional zinc gallium carbonate Layered Double Hydroxide (LDH) phase at higher dopant concentrations. TEM images revealed no significant alteration in the morphology or size of the nanoparticles. ⁷¹Ga-NMR indicated the location of the gallium atoms within the ZnO lattice, showing coordination changes with an increasing dopant concentration. Ga-doped ZnO nanoparticles demonstrated reduced efficiency under UV light compared to commercial references. γ-Ga₂O₃ exhibited superior performance in UV-C for Rhodamine B degradation, diminishing under UV-A, attributed to nanoparticle agglomeration. ZnO and Ga:ZnO catalysts showed optimal performance under green light irradiation, highlighting their performances over the commercial zinc oxide material. Photoluminescence measurements suggested favorable gallium dopant incorporation, with no substantial variation of oxygen vacancies, consequently retaining the photocatalytic properties of ZnO, which are crucial for Rhodamine B degradation under green light irradiation. This study elucidates the intricate relationship among gallium doping, material properties, and photocatalytic performance, providing valuable insights for developing advanced photocatalysts.