Tuning the Properties of Benzothiadiazole Dyes for Efficient Visible Light-Driven Photocatalytic H₂ Production under Different Conditions

Abstract

Photocatalytic hydrogen production has recently emerged as a promising process for the long-term storage of solar energy. In this work, we studied the application of a series of heterogeneous photocatalysts obtained by sensitizing Pt/TiO2 nanoparticles with 10 different D-π-A organic dyes containing the benzo­[c]­[1,2,5]­thiadiazole (BTD) heterocyclic moiety in H2 generation. Starting from the known DSSC sensitizer RK-1, our approach involved the systematic and simultaneous alteration of several important structural features, such as steric bulk and hydrophobicity/hydrophilicity in different parts of the molecules, giving rise to a set of compounds with diverse physico-chemical properties. Visible light-driven H2 generation studies conducted with the dye-sensitized photocatalysts together with different sacrificial electron donors (SEDs) revealed that both their overall hydrogen production efficiency and their relative order of performances could be altered by the choice of SED and the corresponding reaction conditions. In particular, the best results were obtained with dyes having a strongly hydrophobic central core and a hydrophilic donor section in combination with ascorbic acid as the electron donor. In addition, the effect of changing the dye loading and extending the reaction time was examined, resulting in a stable three-component photocatalytic system displaying high activity up to 72 h of experiment.

Platinum Single Atoms Anchored on a Covalent Organic Framework: Boosting Active Sites for Photocatalytic Hydrogen Evolution

“…On the contrary, the rate per unit surface area is associated with the electronic transfer dynamics of the photocatalyst, although it is unable to eliminate all of the uncertain factors for the real photocatalysis . Herein, it is encouraged to compare the photocatalytic reaction rates both per unit weight and per unit surface area of the photocatalyst, which is considered as a more favorable approach for expressing the photocatalytic activity. , From Figure c, it is observed that the order of photocatalytic H 2 evolution rate per surface area is as follows: 3% Pt 1 @TpPa-1 > 5% Pt 1 @TpPa-1 > 3% Pt NPs/TpPa-1 > 1% Pt 1 @TpPa-1 > TpPa-1, which is consistent with the order of photocatalytic H 2 evolution rate per unit mass, and the corresponding overall H 2 production (μmol m –2 ) after 6 h of irradiation is presented in Table . It shows that the 3% Pt 1 @TpPa-1 exhibits the highest photocatalytic H 2 evolution performance per unit surface area (17.24 μmol m –2 ), which is almost 3 and 66 times that of 3% Pt NPs/TpPa-1 (5.64 μmol m –2 ) and bare TpPa-1 (0.26 μmol m –2 ), respectively.…”

“…The number of incident photons in unit time (h –1 ) was calculated using eq Thus, AQE ( i.e ., the apparent quantum yield (AQY)) was calculated using eq , Turnover number (TON) was calculated from the overall amount of H 2 evolved in 6 h during the photocatalytic reaction according to eq ,, Turnover frequency (TOF) is a kinetic-dependent parameter, which was calculated according to eq , …”

Antenna Effect in BODIPY-(Zn)Porphyrin Entities Promotes H2 Evolution in Dye-Sensitized Photocatalytic Systems

“…We have also synthesized the reference chromophores of the dyads, namely, BODIPY ( BDP ), (Zn)­Porphyrin ( Por ), and BDP­(Im) . Overall, BDP-Por and BDP­(Im)-Por reached 17 500 and 13 700 TONs (vs PS), respectively, whereas BDP-Por-BDP­(Im) (18 600 TONs) exhibited a record high H 2 production of 225 mmol­(H 2 ) g­(cat) −1 h –1 with respect to similar noble-metal-free photosensitizers in the literature. ,− …”

Fluorescent Benzothiadiazole Derivatives as Fluorescence Imaging Dyes: A Decade of New Generation Probes

“…The substituent (or substituents) in this sense plays an essential role in the final hydrophobic or hydrophilic character of the ultimate small organic fluorophore; therefore, having a direct effect on the cellular localization or on other biological applications of the BTD dye. The hydrophobic feature of the BTD core is commonly improved by π‐extension (e. g. Ph, C=C or C≡C groups) in the 4,7‐ positions of the structure [54] . It is not rare to see the BTD core described as a hydrophobic structure.…”