Kinetically restrained oxygen reduction to hydrogen peroxide with nearly 100% selectivity

The electrocatalytic oxygen reduction reaction has been investigated in recent years for the production of H2O2 from O-2. In this article, the authors report a single-atom rhodium catalyst, based on the Flavin-dependent oxidase, for this transformation. Hydrogen peroxide has been synthesized mainly through the electrocatalytic and photocatalytic oxygen reduction reaction in recent years. Herein, we synthesize a single-atom rhodium catalyst (Rh-1/NC) to mimic the properties of flavoenzymes for the synthesis of hydrogen peroxide under mild conditions. Rh-1/NC dehydrogenates various substrates and catalyzes the reduction of oxygen to hydrogen peroxide. The maximum hydrogen peroxide production rate is 0.48 mol g(catalyst)(-1) h(-1) in the phosphorous acid aerobic oxidation reaction. We find that the selectivity of oxygen reduction to hydrogen peroxide can reach 100%. This is because a single catalytic site of Rh-1/NC can only catalyze the removal of two electrons per substrate molecule; thus, the subsequent oxygen can only obtain two electrons to reduce to hydrogen peroxide through the typical two-electron pathway. Similarly, due to the restriction of substrate dehydrogenation, the hydrogen peroxide selectivity in commercial Pt/C-catalyzed enzymatic reactions can be found to reach 75%, which is 30 times higher than that in electrocatalytic oxygen reduction reactions.

Automated summary

This article reports the synthesis of a single-atom rhodium catalyst based on flavin-dependent oxidase for the production of hydrogen peroxide. The catalyst exhibits high efficiency and selectivity in the reduction of oxygen to hydrogen peroxide. Compared to electrocatalytic oxygen reduction reactions, the commercial Pt/C-catalyzed enzymatic reactions show higher selectivity for hydrogen peroxide.