Efficient Quasi‐Homogenous Photocatalysis Enabled by Molecular Nanophotocatalysts with Donor‐Acceptor Motif

Abstract Polymer semiconductors have attracted much attention for photocatalytic hydrogen evolution, but they typically exhibit micrometer‐sized particles in water‐suspension, causing severe loss in light absorption and exciton recombination. Here a molecular nanophotocatalyst featuring a donor‐acceptor motif is presented that solution is processed via a facile stirring nanoprecipitation method assisted by hydrophilic surfactants, enabling an efficient quasi‐homogenous hydrogen evolution. In contrast to the original bulk powder (heterogeneous system), these quasi‐homogenous nanophotocatalysts exhibit significantly improved light‐harvesting, water‐wettability, and exciton dissociation, resulting in distinctly enhanced (by four‐order‐of‐magnitude) photocatalytic hydrogen evolution rate. The optimized nanophotocatalysts (4CzPN/DDBAB/SDBS) generate an outstanding hydrogen evolution rate of 116.42 mmol g −1 h −1 and apparent quantum yield of 30.2% at 365 nm, which are among the highest reported for single‐junction organic photocatalysts. The scalability of the quasi‐homogenous photocatalysts is further demonstrated using a flow‐based flash nanoprecipitation (FNP) processing.