Potassium Intercalated into Carbon Nitride Nanosheets as Bifunctional Catalysts for the Simultaneous Photosynthesis and Detection of Hydrogen Peroxide

The photocatalytic production of hydrogen peroxide (H2O2) could provide a green and safe approach for synthesizing H2O2 on demand. However, the common offline methods for the quantitative monitoring of H2O2 concentration are cost-ineffective and not reliable during the in situ photocatalytic process, which is necessary to understand the structure–activity relationship of photocatalysts for H2O2 generation successfully. Herein, we demonstrated a simple and real-time simultaneous photocatalytic production and detection of H2O2 by using potassium (K) ions intercalated into carbon nitride nanosheets (KCN-8). The high crystallinity and K intercalation could synergistically improve the photocatalytic performance of KCN-8. An H2O2 production rate of 158.20 μM mg–1 h–1 was obtained under visible light (λ ≥ 420 nm), which is superior to that of most CN-based photocatalysts. Simultaneously, based on the inherent peroxidase-like property of KCN-8, the colorimetric detection platform of H2O2 was constructed, achieving a precise quantitative detection of H2O2 produced during photocatalysis. Finally, the preparation and detection of H2O2 were realized by KCN-8 nanosheets. This paper not only provides a CN-based catalyst with high photocatalytic performance toward H2O2 production but also demonstrates a cost-effective and real-time method for the quantitative concentration determination of H2O2.