Simultaneous co‐Photocatalytic CO₂ Reduction and Ethanol Oxidation towards Synergistic Acetaldehyde Synthesis

Abstract Photocatalytic conversion of CO 2 is of great interest but it often suffers sluggish oxidation half reaction and undesired by‐products. Here, we report for the first the simultaneous co‐photocatalytic CO 2 reduction and ethanol oxidation towards one identical value‐added CH 3 CHO product on a rubidium and potassium co‐modified carbon nitride (CN‐KRb). The CN‐KRb offers a record photocatalytic activity of 1212.3 μmol h −1 g −1 with a high selectivity of 93.3 % for CH 3 CHO production, outperforming all the state‐of‐art CO 2 photocatalysts. It is disclosed that the introduced Rb boosts the *OHCCHO fromation and facilitates the CH 3 CHO desorption, while K promotes ethanol adsorption and activation. Moreover, the H + stemming from ethanol oxidation is confirmed to participate in the CO 2 reduction process, endowing near ideal overall atomic economy. This work provides a new strategy for effective use of the photoexcited electron and hole for high selective and sustainable conversion of CO 2 paired with oxidation reaction into identical product.