Synergistic Modulation of the Separation of Photo-Generated Carriers via Engineering of Dual Atomic Sites for Promoting Photocatalytic Performance.

The separation efficiency of photo-generated carriers is still a great challenge that restricts the practical application of photocatalytic technology. The design of spatial separation path for photo-generated carriers at atomic level provides an innovative approach to address this challenge. Herein, a facile dual atomic sites strategy, consisting of Cu-N4 and C-S-C active moieties decorated on polymeric carbon nitride (Cu SAs/p-CNS) is reported to simultaneously achieve the highly efficient separation of photo-generated electrons and holes for boosting photocatalytic performance. As a proof of concept, the Cu SAs/p-CNS is successfully applied to the photo-oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-diformylfuran (DFF), which exhibits 77.1% HMF conversion and 85.6% DFF selectivity under visible light irradiation. The activity is considerably higher than that of bulk p-CN, S doped p-CN, and p-CN supported Cu single atom catalysts. Theoretical calculations and experimental results suggest that, during photocatalytic reaction, the isolated Cu-N4 sites directly capture photo-generated electrons, while the surrounding S atoms bear photo-generated holes, which synergistically facilitates the separation of photo-generated carriers and thus results in enhanced photocatalytic activity. This study provides a new perspective for the rational design of high performance photocatalysts at atomic level.