Nb2O5 and Nb based oxides as redox photocatalysts: Partial oxidation of 2-propanol and H2 generation by photoreforming

Abstract

The structural and chemical properties of niobium oxide catalysts have been under scientific scrutiny for the last fifty years; however, their application in photocatalytic processes is very recent and still little studied. In this research, pristine Nb2O5 and its composites containing Ti, Ce, or Zr oxides have been used as photocatalysts in redox reactions such as 2-propanol oxidation in gas-solid regime and in aqueous phase triethanolamine photo-reforming to yield H2. All the materials were active in the oxidation of 2-propanol under simulated sunlight irradiation. The substrate was oxidised in the presence of all of the solids resulting in formation of propanone as the major intermediate product and CO2 as the final product. In liquid solid regime, the H2 production by UV-assisted photoreforming of aqueous solution of triethanolamine reached ca. 6 μmol h−1 g−1 for the best performing material, the bare Nb2O5, which increases up to 592 μmol h−1 g−1 in the presence of 1 % of Pt co-catalyst.