Reduction of Superoxide Radical Intermediate by Polydopamine for Efficient Hydrogen Peroxide Photosynthesis.

The synthesis of hydrogen peroxide through artificial photosynthesis is a green and promising technology with advantages in sustainability, economy and safety. However, superoxide radical (⋅O ₂ ^- ), an important intermediate in photocatalytic oxygen reduction to H ₂ O ₂ production, has strong oxidizing properties that potentially destabilize the catalyst. Therefore, avoiding the accumulation of ⋅O ₂ ^- for its rapid conversion to H ₂ O ₂ is of paramount significance in improving catalyst stability and H ₂ O ₂ yield. In this work, a strategy was developed to utilize protonated groups for the rapid depletion of converted ⋅O ₂ ^- , thereby the efficiency of photocatalytic synthesis of H ₂ O ₂ from CN was successfully enhanced by 47-fold. The experimental findings demonstrated that polydopamine not only improved carrier separation efficiency, and more importantly, provided the adsorption reduction active site for ⋅O ₂ ^- for efficient H ₂ O ₂ production. This work offers a versatile approach for synthesizing efficient and stable photocatalysts.
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