Engineering Nanoparticulate Organic Photocatalysts via a Scalable Flash Nanoprecipitation Process for Efficient Hydrogen Production.

Directly converting sunlight into hydrogen fuels using particulate photocatalysts represents a sustainable route for clean energy supply. Organic semiconductors have emerged as attractive candidates but always suffer from optical and exciton recombination losses with large exciton "dead zone" inside the bulk material, severely limiting the catalytic performance. Herein, we demonstrate a facile strategy that combines a scalable flash nanoprecipitation (FNP) method with hydrophilic soluble polymers ( PC-PEG5 and PS-PEG5 ) to prepare highly efficient nanosized photocatalysts without using surfactants. Significantly, a 70-fold enhancement of hydrogen evolution rate (HER) is achieved for nanosized PC-PEG5 , and the FNP-processed PS-PEG5 shows a peak HER rate of up to 37.2 mmol h -1 g -1 under full-spectrum sunlight irradiation, which is among the highest results for polymer photocatalysts. Moreover, a scaling-up production of nanocatalyst is demonstrated with the continuously operational FNP, which provides an unprecedented strategy toward practical applications of particulate photocatalysts for sustainable energy production.