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Photocatalytic hydrogen evolution using nanocrystalline gallium oxynitride spinel
- Dharmagunawardhane, H. A. Naveen, Woerner, William R., Wu, Quiyan, Huang, Huafeng, Chen, Xianyin, Orlov, Alexander, Khalifah, Peter G., Parise, John B.
- Journal of materials chemistry A 2014 v.2 no.45 pp. 19247-19252
- energy, gallium, hydrogen, hydrogen production, irradiation, lighting, nanocrystals, nitrates, photocatalysis, photocatalysts, ultraviolet radiation
- Photocatalytic hydrogen evolution from water was observed over nanocrystalline gallium oxynitride spinel under simulated solar light irradiation (320 nm < λ < 800 nm). Up to 8 μmol h⁻¹ of H₂ was evolved without co-catalyst loading. The photocatalyst was synthesized by the ammonolysis of gallium nitrate hydrate (Ga(NO₃)₃·xH₂O). Optical measurements indicate an indirect gap (Eg) in the visible region (Eg = 2.50 eV) which is ascribed to photoexcitations from the N 2p valence states. A direct gap has an onset at ultraviolet energies (Eg = 3.69 eV), which is ascribed to photoexcitations from lower energy O 2p valence states.