Direct Synthesis of Formamide from CO 2 and H 2 O with Nickel–Iron Nitride Heterostructures under Mild Hydrothermal Conditions

High Resolution Image Download MS PowerPoint Slide Formamide can serve as a key building block for the synthesis of organic molecules relevant to premetabolic processes. Natural pathways for its synthesis from CO 2 under early earth conditions are lacking. Here, we report the thermocatalytic conversion of CO 2 and H 2 O to formate and formamide over Ni–Fe nitride heterostructures in the absence of synthetic H 2 and N 2 under mild hydrothermal conditions. While water molecules act as both a solvent and hydrogen source, metal nitrides serve as nitrogen sources to produce formamide in the temperature range of 25–100 °C under 5–50 bar. Longer reaction times promote the C–C bond coupling and formation of acetate and acetamide as additional products. Besides liquid products, methane and ethane are also produced as gas-phase products. Postreaction characterization of Ni–Fe nitride particles reveals structural alteration and provides insights into the potential reaction mechanism. The findings indicate that gaseous CO 2 can serve as a carbon source for the formation of C–N bonds in formamide and acetamide over the Ni–Fe nitride heterostructure under simulated hydrothermal vent conditions.