Post-redox engineering electron configurations of atomic thick C3N4 nanosheets for enhanced photocatalytic hydrogen evolution

Polymeric carbon nitride (CN) with atomic thick layers has displayed ultrashort carrier transfer and ion/molecule migration path for enhancement of photocatalytic performance. However, rational modulation towards electron configurations of ultra-thin CN nanosheets is still a challenge, because the existing exfoliation strategies suffer from uncontrollable atom-defects and edge functional groups, leading to poor solar-to-fuel conversion efficiency. Herein, a post-redox method is developed to form atomic thick CN nanosheets with optimized electron configurations through liquid exfoliation and C-reduction. The as-prepared carbon-reduced atomic thick CN (C-AT-CN) expose more active sites, greatly enhance charge carrier mobility and distinctly reduce the optical band gap, thus leading to a remarkably improved photocatalytic hydrogen evolution rate of 246.2 μmol h under visible light irradiation (λ > 420 nm), which is 17-fold higher than that of the pristine counterpart. The apparent quantum efficiency reaches 18.52 % at 420 nm and surpasses most of existing CN-based photocatalysts