Photocatalytic production of H2 and O2 from water based on hybrid enzyme/inorganic semiconductor systems

• Autores: Cristina Tapia Garcia
• Directores de la Tesis: Marcos Pita Martínez (dir. tes.), Antonio López de Lacey (codir. tes.), María Fernández Lobato (tut. tes.)
• Lectura: En la Universidad Autónoma de Madrid ( España ) en 2017
• Idioma: español
• Tribunal Calificador de la Tesis: Francisco José Plou Gasca (presid.), María Elena Casero Junquera (secret.), Eduardo Enciso Rodríguez (voc.), Vincent Artero (voc.), Ines Pereira (voc.)
• Programa de doctorado: Programa de Doctorado en Biociencias Moleculares por la Universidad Autónoma de Madrid
• Materias:
  • Física
    • Química física
      • Catálisis
      • Electroquímica
    • Física del estado sólido
  • Química
    • Bioquímica
• Enlaces
  • Tesis en acceso abierto en: Biblos-e Archivo
• Resumen

  • Water splitting to form hydrogen (H2) and oxygen (O2) is considered a sustainable process for energy conversion. The integration of light-harvesting, multistep transfer of electrons and protons and chemical conversion processes, using water as an electron source and sunlight as an energy source, to synthesize biofuels is the principle of photosynthesis. The global aim of this thesis is the development of inorganic/biological hybrid systems for the artificial photosynthesis of H2 and O2 from water.

    The first approach of this thesis for H2 electrochemical photoproduction was to combine two biological catalysts, photosystem I (PSI) from spinach’s thylakoids as light absorber able to donate high energy electrons, and the [NiFe] hydrogenase from Desulfovibrio gigas, with two hydrogels containing different inorganic redox complexes. This combined photocatalytic system was developed on a gold electrode, which allowed the electron transfer from the electrode to the PSI and then from the PSI to the Hase for H2 evolution. At the same time, the photocurrents derived from the illumination of the system with visible light could be monitored. The aim of the second approach for H2 evolution was based on the combination of In2S3, an inorganic semiconductor able to absorb in the visible light spectral range, with the [NiFeSe] Hydrogenase from Desulfovibrio vulgaris Hildenborough for protons’ reduction. In2S3 was synthesized and characterized for this purpose. This hybrid photocatalytic system was developed by mixing both components in solution and measuring the H2 photoproduction by mass spectrometry.

    The last approach of this thesis was the photoelectrochemical evolution of O2 from water by a hybrid system combining the In2S3 semiconductor with the Trametes hirsuta Laccase, a biocatalyst able to oxidize water to O2. In this case a Fluorine-doped tin oxide (FTO) coated glass was used as electrode substrate, which was drop-coated with In2S3, and the laccase was covalently bound to it. The O2 photoproduction and faradaic yield were estimated according to the registered photocurrents on the electrode and the response of an O2 microsensor placed near to the electrode.