Boosting visible-light-driven hydrogen evolution of polymer photocatalysts by a universal main-chain-engineering strategy of hydrophilic non-conjugated building blocks

Abstract Photocatalytic water splitting is attracting considerable interest because it enables abundant solar energy to be converted into hydrogen for use as a zero-emission fuel or chemical feedstock. Herein, we present a universal approach for inserting hydrophilic non-conjugated building blocks into the main-chain of conjugated polymers to produce a series of discontinuously conjugated polymer (DCP) photocatalysts. Water can effectively be brought into the interior of DCPs through these hydrophilic non-conjugated building blocks, resulting in effective water/polymer interfaces inside the bulk DCPs in both thin-film and solution. P-10HEG with 10 mol% ethylene glycol-based hydrophilic building blocks achieved a record high apparent quantum yield of 17.82% under 460 nm monochromatic light irradiation in solution and an excellent hydrogen evolution rate of 16.8 mmol m− 2 h− 1 in thin-film. Molecular dynamics simulation shows a trend similar to that in experiments, which confirms that main-chain engineering increases the possibility of a water-DCP interaction. Unlike the previous strategy of maintaining a long conjugation length, our approach results in DCP photocatalysts with an interrupted conjugation length that remains efficient photocatalysis.