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Updated: May 27, 2026

Developing Photosensitizer-Cobaloxime Hybrids for Solar-Driven H2 Production in Aqueous Aerobic Conditions
Published on: October 5, 2019
Peptide-linked porphyrin sensitiser and colloidal Pt or Ir catalyst in the H2 formation reaction
Toru Arai1, Seigo Matsumoto, Nao Obata
1Faculty of Engineering, Kyushu Institute of Technology, Kitakyushu, 804-8550, Japan. arai@che.kyutech.ac.jp
Abstract:
Porphyrins linking amphiphilic peptides were applied as photosensitisers, assuming that they would interact with the H(+) reduction catalyst, polymer-protected colloidal Pt or Ir. The close orientation of the porphyrin and metal catalyst may facilitate efficient electron transfer. The porphyrin linking a peptide containing glutamic acids (Glu), Ac-Cys(porph)-Glu-Val-Glu-Val-NH(2) (2), was an effective sensitiser for the H(2) generation reaction in the presence of N-benzyldihydronicotinamide and colloidal Pt or Ir in aqueous media under visible light illumination. At pH 5 and 7, 2 was a more efficient photosensitiser than tetrakis(p-carboxyphenyl)porphyrin (TCPP). The efficiency of H(+) reduction catalysts was in the order Ir-pGlu (polyglutamic acid) > Ir-PVP (polyvinylpyrrolidone) > Pt-PVP. Dynamic light scattering and scanning electron microscopy measurements showed that large particles formed when colloidal metal solutions were produced by microwave irradiation. Fluorescence quenching experiments suggested that electron transfer occurred from the photoexcited porphyrin to the colloidal Ir.
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