Highly crystalline carbon nitrogen polymer with a strong built-in electric fields for ultra-high photocatalytic H2O2 production

Efficient photogenerated charge separation and rapid migration provide more charges for surface redox reactions. Herein, the carbon nitride polymer with highly crystalline is prepared for efficient photocatalytic H2O2 generation. The strong built-in electric field induced by its high crystallinity is beneficial for promoting exciton dissociation, resulting in a surface photovoltage of 19.24 mV. Meanwhile, the formed nanocrystals shorten the charge migration distance to facilitate photogenerated charge rapid migration. The abundant surface −CN/−OH groups provide more active sites for the adsorption of O2. As a result, the photocatalytic H2O2 production rate (16.01 mmol∙L−1∙h−1∙g−1) under visible light (λ > 400 nm) was increased 77-fold relative to pristine graphitic carbon nitride, with a quantum efficiency of 25.1% at 405 nm. The photocatalytic H2O2 production reached 80.36 mM after 8 h. The highly crystalline carbon nitride polymer throws prospect on photocatalytic H2O2 production, showing a new perspective for the design of photocatalysts.