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Identifier

000419387

Title

Σύνθεση και μελέτη πορφυρινικών παραγώγων και συμπλόκων Νικελίου για φωτοκαταλυτική παραγωγή Η2 και DSSCs

Alternative Title

Synthesis and study of porphyrin derivatives and Nickel complexes for light-driven H2 evolution as well as DSSCs

Author

Παναγιωτάκης, Στυλιανός Μ.

Thesis advisor

Κουτσολέλος, Αθανάσιος

Reviewer

Κιτσόπουλος, Θεοφάνης
Αγγαρίδης, Παναγιώτης

Abstract

One world-concern is the transition from the fossil fuels to an economy based on renewable energy sources, because the fossil fuel reserves are getting lower and lower. Nowadays renewable energy sources could be exploited for electric energy production and for the production of a new, clean fuel. One very promising and clean future fuel is hydrogen because the only product from its combustion is water. In addition to that, hydrogen is abundant in nature since it can be received from the water of the oceans. DSSCs have attracted wide scientific attention due to their promising, alternative and low cost ability for photovoltaic transition of sun light into electricity. In this Master thesis porphyrin derivatives and nickel based complexes were synthesized and investigated for DSSCs applications and for photocatalytic hydrogen production. All compounds were characterized via NMR, Uv-Vis spectroscopies and via mass spectrometry. In the first part of this thesis, two porphyirin derivatives bearing Zn (II) as metal centre and cyanoacrilic group as anchoring group to TiO₂ nanoparticles were synthesized and used as photosensitizers. The porphyrin derivatives are named ZnPCNCOOH and ZnP(SP)CNCOOH, the second derivative is bearing a π-spacer between the porphyrin ring and the anchoring group. The two compounds were studied with cyclic voltammetry and theoretical calculations DFT. Solar cells from these derivatives were constructed and reached 5.02% and 7.61% yield respectively. In the second part of this thesis two porphyrins bearing Pt (ΙΙ) (PtPCOOH) and Pd (ΙΙ) (PdPCOOH) were synthesized. Common chemical characteristic is the di-carboxy group which could serve as an anchoring group for TiO₂ nanoparticles and the extended conjugation between the porphyrin ring and the anchoring group. In the third part, the photocatalytic reactivity of four Ni based catalysts was examined for photocatalytic hydrogen evolution. The Ni complexes contain two nitrogen atoms and two sulfur atoms in the first coordination sphere (Ligand thiosemicarbazone). Their difference is the characteristic group on Thiosemicarbazone Ligand. These catalysts were tested with five different chromophores and two different sacrificial electron donors. The best results were obtained from the catalyst with the methoxy (-OMe) group which is named NiTSCOMe, an iridium complex [Ir(ppy) ₂ (bipy)PF₆] as photosensitizer and TEA as sacrificial electron donor. This photocatalytic system reached 11333 ΤΟΝs under 2 h of radiation. The photochemical stability and mechanism of these systems was also studied with UV-Vis and Fluorescence spectroscopy and Hg experiments.

Language

Greek

Subject

Cyanoacrilic group

Di-carboxy group

Hydrogen production

Paladium

Photocatalyst

Platinum

Thiosemicarbazone Ni complexes

Zinc

Δικαρβοξιλική ομάδα