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.