Using block copolymers to enhance photosensitized water reduction for hydrogen gas generation

Gold nanoparticle-catalysed photosensitized water reduction for hydrogen generation

“…2,5,12,14,15 The mechanism of our system is depicted in Scheme 1. First, based on the previous studies, 27,30 the diblock copolymer PAA 52b-P4VP 90 could form micelles with a hydrophobic P4VP core and a hydrophilic PAA corona. Consequently, water-insoluble dye molecules, such as ZnPP, are solubilized by the PAA 52 -b-P4VP 90 polymer micelle to form the ZnPP-polymer complex through axial coordination between Zn and the pyridyl group, as shown in Scheme 1.…”

“…33 Before irradiation, all the absorption and emission spectra of the water splitting solutions containing AuNPs of different concentrations or K 2 PtCl 4 are similar. Those spectra indicate that the hydrophobic ZnPP photosensitizer is well solubilized by the polymer micelles through the axial coordination between pyridine and ZnPP, 14,27,34 as revealed by the large shi of the Q bands. Aer This journal is © The Royal Society of Chemistry 2015 irradiation for 10 hours, changes in the absorption and emission spectra were observed.…”

“…23 However, to our knowledge, the catalytic properties of AuNPs in the conventional, and most common, threecomponent systems for photosensitized water reduction leading to hydrogen have rarely been demonstrated. 26 To address this issue, in a previous study, 27 we showed that water-insoluble ZnPP could be loaded in low-cost micelles of an amphiphilic diblock copolymer of poly(acrylic acid) and poly(4-vinylpyridine) (PAA 52 -b-P4VP 90 ) through the axial coordination between Zn and the pyridyl group, making possible the photosensitized water reduction using the conventional three-component system with Pt as the catalyst. These are long wavelength absorption dyes and would be highly efficient in harvesting the solar energy; but the aggregation of the dyes due to low water solubility would highly quench the triplet state, which hinders the electron transfer necessary for reducing the water molecules.…”

“…14 But the drawback is the high cost of the protein 14 or hydrogenase. 26 To address this issue, in a previous study, 27 we showed that water-insoluble ZnPP could be loaded in low-cost micelles of an amphiphilic diblock copolymer of poly(acrylic acid) and poly(4-vinylpyridine) (PAA 52 -b-P4VP 90 ) through the axial coordination between Zn and the pyridyl group, making possible the photosensitized water reduction using the conventional three-component system with Pt as the catalyst.…”

Block copolymer micelles as efficient colloidal photosensitizers in the light-driven hydrogen evolution reaction

“…The first study about the utilization of block copolymer micelles in visible light-driven HER was provided in 2013. 33 Here, poly(acrylic acid)- block -poly(4-vinylpyridine) (PAA- b -P4VP) block copolymers were utilized in the first step as ligands for a water-insoluble zinc protoporphyrin IX (ZnPP) as a photosensitizer. Light-driven hydrogen evolution was achieved using [Rh(bpy) 3 ] 3+ as an electron relay (ER) and Pt-NPs as a HER-CAT.…”