Now showing 1 - 3 of 3
  • Publication
    Photo-active and dynamical properties of hematite (Fe2O3)-water interfaces: An experimental and theoretical study
    The dynamical properties of physically and chemically adsorbed water molecules at pristine hematite-(001) surfaces have been studied by means of equilibrium Born–Oppenheimer molecular dynamics (BOMD) in the NVT ensemble at 298 K. The dissociation of water molecules to form chemically adsorbed species was scrutinised, in addition to ‘hopping’ or swapping events of protons between water molecules. Particular foci have been dynamical properties of the adsorbed water molecules and OH− and H3O+ ions, the hydrogen bonds between protons in water molecules and the bridging oxygen atoms at the hematite surface, as well as the interactions between oxygen atoms in adsorbed water molecules and iron atoms at the hematite surface. Experimental results for photoelectrical current generation complement simulation findings of water dissociation.
      468Scopus© Citations 26
  • Publication
    Photo-active and optical properties of bismuth ferrite (BiFeO3): an experimental and theoretical study
    An experimental and a hybrid density functional theory study of the photo-active and optical properties of bismuth ferrite are presented. Phase-pure photo-catalytically active BFO was prepared experimentally with a 28% degradation of methyl orange observed over a 7- hour period. Direct and indirect band gaps were measured to be 2.10 and 1.92 eV, respectively. BFO was also studied computationally with the use of hybrid density functional theory, quite suitable for such a multiferroelectric material. This led to excellent, semiquantitative agreement between hybrid DFT and experimental approaches for absorption coefficients.
      2425Scopus© Citations 65
  • Publication
    The influence of Ti and Si doping on the structure, morphology and photo-response properties of α-Fe2O3 for efficient water splitting: experiment and first-principle calculations
    Ti- and Si- doping effects on morphology, structure, optical and photo-response of α-Fe2O3 nanoscale coatings from atmospheric-pressure chemical vapour deposition (APCVD) have been studied. Si- and Ti-doping led to larger clusters with finer grains and smaller clusters with larger grains, respectively. Photocurrent performance was increased remarkably by doping, especially Si. Excellent agreement was found for band gaps and optical properties compared to hybrid-Density Functional Theory. Substitutional replacement of Fe by Si shrinks the volume more than Ti-doping; it is conjectured that this affects hopping probability of localised charge-carriers more and leads to enhanced photocurrent activity for Si-doping, supported by experiment.
      565Scopus© Citations 18