Organic Electron Donor‐Acceptor Co‐intercalated NiMn‐LDHs – Photocatalysts with Enhanced Separation of Charge Carriers for Photocatalytic Reduction of CO2

Developing good photocatalysts for reducing CO2 to carbonaceous fuels has aroused interest. However, the efficiency of photocatalytic CO2 reduction remains low. In this work, we report a novel organic electron donor‐acceptor system to realize the two dimensional photoinduced electron transfer (PET) process by coprecipitation‐in situ oxidation method to synthesize 4,4′‐diaminostilbene‐2,2′‐disulfonic acid (DAS) and 4,4′‐dinitrostilbene‐2,2′‐disulfonic acid disodium salt (DNS) co‐intercalated Ni2Mn‐LDHs (Ni2Mn‐LDHs‐DAS, DNS). Due to the two‐dimensional confinement of LDHs, DAS and DNS were arranged in a single molecule parallel in the interlayer, resulting in a π‐π interaction between the two organic anions. It promoted the photogenerated electrons by the DAS‐DNS to migrate to the hydrotalcite layer to participate in CO2 photoreduction rather than recombination with the holes. The optimum Ni2Mn‐DAS, DNS‐n showed the highest total consumed electron number of 13.99 μmol g−1, which was 3 times higher than that of Ni2Mn−CO3. Our findings provide a new way for improving the CO2 photoreduction activity of hydrotalcite‐based photocatalysts and achieve the combination of organic and inorganic semiconductors. Using of the two‐dimensional confinement effect of LDHs, two kinds of organic anion, DAS and DNS, were co‐intercalated and created the π‐π conjugation. The π‐π interaction contributed to separation of the photogenerated electron‐hole and enhanced the efficiency of CO2 reduction. At the same time, the light absorption ability of the Ni2Mn‐LDHs was enhanced due to the combination with organic anions.