Effect of energy bandgap and sacrificial agents of cyclopentadithiophene-based polymers for enhanced photocatalytic hydrogen evolution

A library of donor-acceptor system consisting of cyclopentadithiophene-based polymer photocatalysts have been designed and synthesized. Among all photocatalysts, the active PCPDTBSO achieved hydrogen evolution rates of 24.6 mmol h^–1 g^–1 with apparent quantum yields of 8.7 % at 500 nm. More importantly, combined the results of photocatalytic efficiency, apparent quantum yield, the time-resolved fluorescence decay spectra, the steady-state photoluminescence spectra, and the transient absorption spectroscopy, and the oxidation potentials of sacrificial donors and protons reduction potentials in different pH values, we confirmed the concept that ascorbic acid is a suitable sacrificial donor for narrow bandgap polymers and triethylamine is a suitable sacrificial donor for wide bandgap polymers owing to the existence of the optimal thermodynamic driving force. We believed this study would be advantageous for the selection of photocatalysts and sacrificial donors for hydrogen production.