Ultrathin carbon nitride (CN) nanosheets are prepared by a facile, low-cost, and highly efficient strategy through green self-exfoliation without using any acid, base, or solvents. As-prepared CCNK catalysts exhibit an impressive photocatalytic hydrogen evolution activity (132.6 μmol h−1), which is 22 times higher than bulk CN and far surpasses other CN-based photocatalysts.
The recombination of photogenerated electron-hole pairs severely limits the efficiency of solar-driven hydrogen evolution in carbon nitrides (CN) system. Herein, a K+ doped and cyanamide defects modified CN (CCNK) with free-standing nanosheets in water was synthesized by a bottom-up self-exfoliated strategy. Further experimental characterizations reveal that the cyanamide moiety and K+ in the framework play an important role in the enhancement of hydrophilicity and efficiently suppress electron-hole pair recombination. CCNK exhibits an impressive photocatalytic hydrogen evolution activity (132.6 μmol h−1), which is 22 times higher than bulk CN (6.0 μmol h−1), and far surpassing other CN-based photocatalysts. This work provides an innovative facile self-exfoliated strategy for bottom-up preparation of ultrathin CN nanosheets without using any acid, base, or solvents, paving the way for the development of high-performance photocatalysts using CN-based powders.Zum Volltext