Dye-sensitized photocatalytic hydrogen production: distinct activity in a glucose derivative of a phenothiazine dye

Abstract

A thiophene-based donor-acceptor phenothiazine dye has been functionalized with a peripheral glucose unit (PTZ-GLU) to bust its affinity to water and enhance dye-sensitized photogeneration of hydrogen. Compared to the corresponding alkyl derivative (PTZ-ALK), as well as the common hydrophilic triethylene glycol substitution (PTZ-TEG), the sugar derivative shows a lower contact angle; PTZ-GLU performed twice more efficient than PTZ-TEG in the photogeneration of hydrogen in terms of evolved gas and turnover number.

Dye‐Sensitized Solar Cells that use an Aqueous Choline Chloride‐Based Deep Eutectic Solvent as Effective Electrolyte Solution

“…To improve the hydrophilic nature of the dye, glycolic chains can be used . We have met these requirements in the design and investigation of organic dyes for photocatalytic hydrogen production in water . In particular, the selected sensitizer is a donor–acceptor phenothiazine (PTZ) molecule that contains thiophene‐based spacers and is characterized by the presence of a terminal tris(ethylene glycol) monomethyl ether (TEG) substituent (PTZ‐TEG; Figure ).…”

Photocatalytic Hydrogen Production: A Rift into the Future Energy Supply

“…Traditionally, wide spectral response has been achieved by introducing impurities or incorporating sensitizers. Narrowing the band‐gap energy has been accomplished via band gap engineering using dopants, whereas organic dyes, transition metal complexes, or even narrow band‐gap SCs have been used as visible light sensitizers. Besides metal oxides, several metal chalcogenides possess suitable E g and band‐edge position for H 2 production under visible light irradiation .…”

Towards Sustainable H2 Production: Rational Design of Hydrophobic Triphenylamine‐based Dyes for Sensitized Ethanol Photoreforming

“…For instance, it has been recently shown that hydrophilic substituents placed on the terminal portion of organic dyes can enhance their affinity towards the aqueous environment used in the experiments, thus improving catalytic performances by favoring the interaction with reactants in solution. On the other hand, positioning hydrophobic side chains on dye molecules could also have a positive impact on H 2 production as they should prevent adsorption of water on the TiO 2 surface, reducing the possibility of dye deactivation/desorption from the semiconductor.…”

“…For instance, it hasbeen recently shown [18,19] that hydrophilic substituents placedo nt he terminal portion of organic dyes can enhance their affinity towards the aqueous environment used in the experiments, thusi mproving catalytic performances by favoring the interaction with reactants in solution. On the other hand, positioningh ydrophobic side chains on dye molecules coulda lso have ap ositive impact on H 2 production as they shouldp revent adsorption of water on the TiO 2 surface, reducing the possibility of dye deactivation/desorption from the semiconductor.F urthermore, in analogy to what happens in dye-sensitized solar cells, [11] hydrophobic side chains should also be able to suppressu ndesirable dye aggregation and increase the stability of oxidized dyes by preventing fast charger ecombination between them and electrons in the conductionb and of TiO 2 as well as protecting them from the attack of nucleophilic species presenti nt he reactione nvironment.…”