Simulation and experimentation of iron-doped liquid metal-based gallium oxide photocatalysts for environmental applications harnessing solar energy

Gallium-based liquid metals (GLM) have emerged as promising materials for cutting-edge technologies. However, their increased use raises environmental concerns. Sustainable strategies, such as using them as nanophotocatalyst precursors, can help mitigate these impacts. In this work, gallium oxides doped with different atomic ratios of Ga:Fe (100:0, 80:20, 70:30, and 50:50) were synthesized from GLM, characterized, and evaluated in the degradation of an emergent pollutant (acetaminophen). The study considers theoretical modeling through the density functional theory. The photocatalysts were characterized by different techniques to investigate and corroborate the effect of iron on the structural, optical, and morphological properties. The results showed that Fe content influences the properties of gallium oxides. After Fe doping, the band gap of FeGO_x decreases to 3.21-2.78 eV. All materials showed photocatalytic activity in the visible region ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow><mml:msub><mml:mi>k</mml:mi> <mml:mn>1</mml:mn></mml:msub> <mml:mo>=</mml:mo> <mml:mn>0.00324</mml:mn> <mml:mo>-</mml:mo> <mml:mn>0.00562</mml:mn></mml:mrow> </mml:math> min <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mmultiscripts><mml:mrow></mml:mrow> <mml:mrow></mml:mrow> <mml:mrow><mml:mo>-</mml:mo> <mml:mn>1</mml:mn></mml:mrow> </mml:mmultiscripts> </mml:math> under visible illumination), reaching 65-80% mineralization under visible light, with similar performances under UVA light, making them suitable for use under solar radiation. Among the synthesized materials, FeGO₃₀ displayed the best structural, optical, and morphological properties. Theoretical and experimental results are consistent. Several experiments were conducted using electron, proton, superoxide, and hydroxyl radical scavengers, suggesting that the reaction mechanism of Ac degradation could occur via HO^• radicals or oxidation through holes. Additionally, a band diagram is proposed for the FeGO_x materials.