Hydrophobic and Hydrophilic Conjugated Polymer Dots as Binary Photocatalysts for Enhanced Visible-Light-Driven Hydrogen Evolution through Förster Resonance Energy Transfer

Abstract

Organic semiconducting polymers exhibited promising photocatalytic behavior for hydrogen (H 2 ) evolution, especially when prepared in the form of polymer dots (Pdots). However, the Pdot structures were formed using common nonconjugated amphiphilic polymers, which have a negative effect on charge transfer between photocatalysts and reactants and are unable to participate in the photocatalytic reaction. This study presents a new strategy for constructing binary Pdot photocatalysts by replacing the nonconjugated amphiphilic polymer typically employed in the preparation of polymer nanoparticles (Pdots) with a low-molecular-weight conjugated polyelectrolyte. The asprepared polyelectrolyte/hydrophobic polymer-based binary Pdots truly enhance the electron transfer between the Pt cocatalyst and the polymer photocatalyst with good water dispersibility. Moreover, unlike the nonconjugated amphiphilic polymer, the photophysics and mechanism of this photocatalytic system through time-correlated single-photon counting (TCSPC) and transient absorption (TA) measurements confirmed the Forster resonance energy transfer (FRET) between the polyelectrolyte as a donor and the hydrophobic polymer as an acceptor. As a result, the designated binary Pdot photocatalysts significantly enhanced the hydrogen evolution rate (HER) of 43 900 μmol g −1 h −1 (63.5 μmol h −1 , at 420 nm) for PTTPA/PFTBTA Pdots under visible-light irradiation.

Construction of Porous Organic/Inorganic Hybrid Polymers Based on Polyhedral Oligomeric Silsesquioxane for Energy Storage and Hydrogen Production from Water

“…Using a gas-tight syringe, the hydrogen sample was taken every hour and injected in a Shimazhu GC-2014 gas chromatograph, using Ar as the carrier gas. Hydrogen was detected with a thermal conductivity detector, referring to the standard hydrogen gases with known concentrations [ 62 , 63 ].…”

Impact of Interfaces, and Nanostructure on the Performance of Conjugated Polymer Photocatalysts for Hydrogen Production from Water

“…Other strategies in this area have led to appreciable results, including the use of different surfactants, morphology control to obtain more hollow PDots, modulation of the hydrophobic and hydrophilic constituents to optimize the micelle morphology, and even their use in biohybrid systems owing to their tunable surface morphology and pH stability [ 161 , 162 , 163 , 164 ]. Nevertheless, in general these examples of using PDots for photocatalytic HER emphasize the photophysical processes as the significant contributing factors to enhanced activity.…”

“…Reports of carbon nitride nanosheets emerged first in the field, with many reports that develop activity enhancement through heteroatom doping and defect engineering for instance [ 150 , 163 , 164 ]. Progress has now been made using conjugated polymer based nanosheets, and promising results have been reported [ 165 ].…”

“…Nanoparticles with the amphiphilic polymer PS-PEG-COOH show poor photocatalytic performance as the platinum co-catalyst appears to be interacting with the nonconjugated PS-PEG-COOH on the surface of the nanoparticles. Nanoparticles that use conjugated electrolytes allow for Förster resonance energy transfer-type electron transfer to take place and fast electron transfer from the conjugated electrolyte to platinum, which results in a significant increase in photocatalytic activity [ 163 ].…”

Overcoming Small-Bandgap Charge Recombination in Visible and NIR-Light-Driven Hydrogen Evolution by Engineering the Polymer Photocatalyst Structure

“…1,2,3,4,5 However, the hydrophobic nature of the majority of conjugated polymers counts as a problem that minimizes their water dispersity 6, 7, 8 so some amphiphilic surfactants utilized to convert the pulk polymer to polymer nanoparticles (Pdot) which enhanced their water dispersity, increase the active area and reduce the diffusion length of the charge carrier. 9,10,11,12 Many series of conjugated polymers have been reported as photocatalysts for hydrogen production under UV and visible light irradiation without including the near-infrared (NIR) region, which represents more than 50% of the solar radiation spectrum. 13,14,15,16,17,18,19 Full harvesting of solar light (from the visible to NIR region) is always the goal and a major challenge for photocatalysts, particularly for the new approach of conjugated polymer photocatalysts because of the insu cient photocatalytic activity of narrow bandgap semiconductors, the direct conversion of NIR light energy into heat, or the low photon energy of NIR light.…”