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

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.