Tuning on and off chemical- And photo-activity of exfoliated MoSe2nanosheets through morphologically selective 'soft' covalent functionalization with porphyrins
| Autor: | Matías Blanco, Marco Bortoli, Dario Mosconi, Stefano Agnoli, Leonardo Girardi, Marco Lunardon, Gaetano Granozzi, Laura Orian |
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| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
chemistry.chemical_classification
Renewable Energy Sustainability and the Environment Heterojunction 02 engineering and technology General Chemistry 010402 general chemistry 021001 nanoscience & nanotechnology Photochemistry 01 natural sciences 0104 chemical sciences X-ray photoelectron spectroscopy Transition metal chemistry Covalent bond Thiol Molecule General Materials Science Fourier transform infrared spectroscopy 0210 nano-technology Hybrid material |
| Popis: | The covalent functionalization of 2D transition metal dichalcogenides (TMDCs) with organic molecules exploiting the thiol conjugation approach is still a very controversial topic. We have synthesized thiolated tetraphenyl porphyrins, with and without hydroxyl groups in the phenyl substituents, which have been covalently attached to chemically exfoliated MoSe2 (ce-MoSe2) nanosheets. XPS and FTIR have revealed the formation of sulfo-selenide bridges, specifically on the edges of the ce-MoSe2, as confirmed by first principles calculations. The electrocatalytic activity of TMDCs in the hydrogen evolution reaction (HER) has been investigated after conjugation with the organic molecules. The HER activity is suppressed or enhanced according to the presence of mildly acidic hydroxyl groups in the attached molecules, since they provide a local proton relay boosting the production of H2, especially under mildly acidic conditions (pH = 4.3). Moreover, the well-known light-harvesting properties of porphyrins have been exploited to improve significantly the light-assisted HER activity. Due to the formation of a type II heterojunction or Schottky contact between the molecules and the 2H and 1T MoSe2 nanosheets respectively, the hybrid materials show an improvement of the HER onset potential under illumination compared to the pristine material, without activity loss for more than 16 h. |
| Databáze: | OpenAIRE |
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