Abstract
Through tuning of interfacial interactions between hydrophobic and hydrophilic polymers, as well as between polymer dots and water, a substantial enhancement in the photocatalytic hydrogen evolution efficiency of polymer dots is achieved. This improvement is directly correlated with the optimal degrees of saponification and molecular weights of the hydrophilic polymers.
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•Four new binary mixtures of hydrophilic-hydrophobic conjugated polymer dots are successfully synthesized.•The effects of varying saponification degrees and molecular weights of hydrophilic polymers are investigated.•Optimal ratios of the binary mixtures are explored for the first time to enhance photocatalytic hydrogen evolution.•P2c/P3 Pdots exhibit improved charge transfer and an increased hydrogen evolution rate (HER) compared to other mixtures.
Conjugated polymer dots (Pdots) are promising photocatalysts for solar hydrogen production, yet the impact of molecular weight and saponification degree on their performance remains underexplored. In this study, we synthesize hydrophobic polymers based on thiophene-terephthalate ester (P1a and P1b) and cyclopentadithiophene-dibenzothiophene-dioxide (P3) using direct C–H arylation polymerization. P1a and P1b polymers with varying molecular weights are partially saponified to produce hydrophilic derivatives (P2a–P2d), which are blended with the hydrophobic P3 polymer to form binary Pdots (P2a–P2d/P3 Pdots). The combination of a higher molecular weight, partially saponified hydrophilic polymer with the hydrophobic polymer (P2c/P3 Pdots) exhibits the highest hydrogen evolution rate (HER) of 8.93 mmol g−1h−1. The femtosecond transient absorption (ft-TA) spectroscopy further confirmed the enhanced ability of P2c/P3 Pdots for ultrafast electron transfer to Pt sites and reduced recombination effects. This enhanced performance is attributed to the retained partial hydrophobicity, which promotes optimal compatibility and solubility between the two polymer types, highlighting the potential of adjusting the saponification degrees and molecular weights of hydrophilic polymers in two binary conjugated polymers as a promising strategy for developing efficient photocatalysts for solar-driven hydrogen production.