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

The photocatalytic production of hydrogen peroxide (H 2 O 2 ) could provide a green and safe approach for synthesizing H 2 O 2 on demand. However, the common offline methods for the quantitative monitoring of H 2 O 2 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 H 2 O 2 generation successfully. Herein, we demonstrated a simple and real-time simultaneous photocatalytic production and detection of H 2 O 2 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 H 2 O 2 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 H 2 O 2 was constructed, achieving a precise quantitative detection of H 2 O 2 produced during photocatalysis. Finally, the preparation and detection of H 2 O 2 were realized by KCN-8 nanosheets. This paper not only provides a CN-based catalyst with high photocatalytic performance toward H 2 O 2 production but also demonstrates a cost-effective and real-time method for the quantitative concentration determination of H 2 O 2 .