Decoupled Solar Energy Conversion and Charge Storage in a Carbon‐Doped Sodium Poly(heptazine imine) for Dark Photocatalysis

The direct coupling of solar energy conversion and charge storage in a single material can provide new ideas for making energy‐storage devices. Furthermore, it can enable solar energy utilization in the dark. In this study, we successfully constructed carbon‐doped sodium poly(heptazine imine) by introducing barbituric acid into the synthetic process. In the presence of sacrificial agents and illumination, the resulting Na‐PHI‐BA sample has been shown to effectively store electrons and charge‐balancing protons. Subsequently, the stored electrons/protons can react with oxygen in the dark to produce hydrogen peroxide, thereby achieving the decoupling of light and dark reactions. Owing to the superior charge separation efficiency, Na‐PHI‐BA demonstrates enhanced photocharge storage capacity in comparison with the original Na‐PHI. Compared with the previously reported “dark” photocatalysis, the present catalytic system has achieved higher H 2 O 2 production (943.5 μmol g −1 ) with nearly stoichiometric amount of sacrificial agent. This study offers novel insights into the design of photocharge‐storing materials and the utilization of photocharges in the synthesis of high‐value‐added chemicals.