Main-chain engineering of polymer photocatalysts with hydrophilic non-conjugated segments for visible-light-driven hydrogen evolution
Chih‐Li Chang, Wei‐Cheng Lin, Li‐Yu Ting, Chin‐Hsuan Shih, Shih-Yuan Chen, Tse‐Fu Huang, Hiroyuki Tateno, Jayachandran Jayakumar, Wen‐Yang Jao, Chen‐Wei Tai, Che‐Yi Chu, Chin‐Wen Chen, Chi‐Hua Yu, Yu‐Jung Lu, Chi‐Chang Hu, Ahmed M. Elewa, Takehisa Mochizuki, Ho‐Hsiu Chou
Abstract
Abstract Photocatalytic water splitting is attracting considerable interest because it enables the conversion of solar energy into hydrogen for use as a zero-emission fuel or chemical feedstock. Herein, we present a universal approach for inserting hydrophilic non-conjugated segments into the main-chain of conjugated polymers to produce a series of discontinuously conjugated polymer photocatalysts. Water can effectively be brought into the interior through these hydrophilic non-conjugated segments, resulting in effective water/polymer interfaces inside the bulk discontinuously conjugated polymers in both thin-film and solution. Discontinuously conjugated polymer with 10 mol% hexaethylene glycol-based hydrophilic segments achieves an apparent quantum yield of 17.82% under 460 nm monochromatic light irradiation in solution and a hydrogen evolution rate of 16.8 mmol m −2 h −1 in thin-film. Molecular dynamics simulations show a trend similar to that in experiments, corroborating that main-chain engineering increases the possibility of a water/polymer interaction. By introducing non-conjugated hydrophilic segments, the effective conjugation length is not altered, allowing discontinuously conjugated polymers to remain efficient photocatalysis.