Photocatalytic Hydrogen Production with Conjugated Polymers as Photosensitizers

Abstract

Artificial photosynthesis is a chemical process that aims to capture energy from sunlight to produce solar fuels. Light absorption by a robust and efficient photosensitizer is one of the key steps in solar energy conversion. However, common photosensitizers, including [Ru(bpy)] (RuP), remain far from the ideal. In this work, we exploited the performance of conjugated polymers (CPs) as photosensitizers in photodriven hydrogen evolution in aqueous solution (pH 6). Interestingly, CPs, such as poly(fluorene- co-phenylene) derivative (429 mmol·g·h), exhibit steady and high reactivity toward hydrogen evolution; this performance can rival that of a phosphonated RuP under the same conditions, indicating that CPs are promising metal-free photosensitizers for future applications in photocatalysis.

A Time-Resolved Spectroscopic Investigation of a Novel BODIPY Copolymer and Its Potential Use as a Photosensitiser for Hydrogen Evolution

“…The ns-TA spectrum (Figure 7) exhibits a broad GSB in addition to two ESA features at ∼435 and 585 nm, which resembles the final spectrum obtained in the ps-TA experiments described above. The triplet lifetime of 60 µs is similar to triplet state lifetimes measured for other conjugated polymers containing thiophene and fluorene moieties previously measured (20-120 µs) (Yong et al, 2018). Lifetimes in the range 450-710 µs have been reported for polymers with pendant iodosubstituted BODIPY units (Zhang et al, 2020).…”

“…For instance Zhang et al reported the use of poly(fluorene-co-phenylene) as a photosensitiser (PS) for hydrogen generation. When used in conjunction with a Ni catalyst and EDTA as a sacrificial agent, efficiencies of up to 429 mmol g −1 h −1 were achieved (Yong et al, 2018). Graphitic carbon nitride (g-C 3 N 4 ) based polymers have also been investigated because of their thermal stability and high hydrogen evolution rates (HER) (Ong et al, 2016;Wang et al, 2017), although they require post-modification, such as surface functionalisation or surface assembly to maximise hydrogen evolution (Ran et al, 2018;Wang et al, 2020;Yi et al, 2020).…”

AIEE Active Nanoassemblies of Pyrazine Based Organic Photosensitizers as Efficient Metal-Free Supramolecular Photoredox Catalytic Systems

“…These observations led us to propose that assemblies of TETPY are reductively quenched by a sacrificial donor to generate radical anion ( TETPY *− ) which in turn transports electron to MV 2+ and reduce it (Fig. 3B) 20 . The blue colored radical cation persisted for 2 h and was slowly reoxidized upon exposure to aerial conditions.…”

Pyrazine Based Type‐I Sensitizing Assemblies for Photoreduction of Cu(II) in ‘One‐Pot Three‐Component’ CuAAC Reaction Under Aerial Conditions

“…Thereafter, we examined the sensitization potential of PDA assemblies in the electron transportation experiment using the methyl viologen (MV 2 + ) as the electron acceptor and triethanolamine (TEOA) as the sacrificial donor (Figure S12). [30] These studies support the transportation ability of PDA assemblies in 8 minutes. Next, the potential of PDA assemblies to reduce molecular oxygen (À 0.33 eV vs SHE) [31] to generate reactive oxygen species (ROS) was confirmed by using N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD) as the indicator (Figure S13).…”