Organic Polymer Dots Photocatalyze CO 2 Reduction in Aqueous Solution

Developing low‐cost and efficient photocatalysts to convert CO 2 into valuable fuels is desirable to realize a carbon‐neutral society. In this work, we report that polymer dots (Pdots) of poly[(9,9′‐dioctylfluorenyl‐2,7‐diyl)‐ co ‐(1,4‐benzo‐thiadiazole)] (PFBT), without adding any extra co‐catalyst, can photocatalyze reduction of CO 2 into CO in aqueous solution, rendering a CO production rate of 57 μmol g −1 h −1 with a detectable selectivity of up to 100 %. After 5 cycles of CO 2 re‐purging experiments, no distinct decline in CO amount and reaction rate was observed, indicating the promising photocatalytic stability of PFBT Pdots in the photocatalytic CO 2 reduction reaction. A mechanistic study reveals that photoexcited PFBT Pdots are reduced by sacrificial donor first, then the reduced PFBT Pdots can bind CO 2 and reduce it into CO via their intrinsic active sites. This work highlights the application of organic Pdots for CO 2 reduction in aqueous solution, which therefore provides a strategy to develop highly efficient and environmentally friendly nanoparticulate photocatalysts for CO 2 reduction.