Boosting Photocatalytic CO2 Reduction of Metal-Organic Frameworks by Encapsulating Carbon Dots
Photocatalytic CO2 reduction is a promising technology to mitigate the global warming and enrich energy supply. Metal-organic frameworks (MOFs) are prospective photocatalysts for CO2 reduction, but severe charge recombination and limited visible light response largely restrain their applications. As carbon dots (CDs) can act as both electron receptors and photosensitizers, here we propose to develop CD-hybridized MOF photocatalysts for improving their activity for CO2 reduction. In particular, because of the small size of CDs, we have managed to encapsulate CDs inside MOF particles and found these CD@MOFs exhibit hugely improved photocatalytic activity compared with CD-decorated MOFs or pristine MOFs. Our investigations suggest that placing small CDs cocatalyst near the internal metal-oxo clusters of MOFs can help efficient charge transfer and separation in the hybrid catalysts, due to the formation of many small heterojunctions among MOFs. The developed CD-hybridized MOFs catalysts have been characterized in detail and their working mechnism is explored. This work may demostrate a novel strategy to largely improve the photocatalytic activity of MOF-based photocatalyst by engineering the location of small cocatalysts.