Photothermal catalysis over core-shell Cu/Cu2O catalyst for overall N2 fixation from air

Industrial nitrogen fixation processes, such as the Haber-Bosch and Ostwald processes, are energy-intensive and cause environmental issues. Here, a photothermal evaporation catalytic evaporator was constructed using a core-shell Cu/Cu 2 O (Copper/ Copper(I) oxide) catalyst supported on carbon foam (CF) for efficient overall nitrogen fixation under air. The evaporator utilized the localized surface plasmon resonance (LSPR) effect of Cu nanoparticles and the excellent photothermal conversion capability of CF. It could achieve a surface temperature of 362.2°C under full spectrum light intensity of 1500 mW·cm −2 . The gaseous reaction environment generated by this photothermal evaporator overcame the low solubility of conventional photocatalytic N 2 in water and enhanced mass transfer. The Cu/Cu 2 O interface promoted charge separation, and the hot carriers from Cu nanoparticles accelerated the activation of N 2 . Meanwhile, the charge transfer process between the interfaces (Cu 0 -e - →Cu + , O 2- -e - →OV (Oxygen vacancy), Cu + +e - →Cu 0 , O 2 filled OV) made it possible to ensure the structural integrity throughout the reaction cycle. Under air conditions, the evaporator yield rate of NH 4 + and NO 3 - reached 691.96 μmol g −1 h −1 and 423.87 μmol g −1 h −1 , respectively, surpassing most reported catalysts. In-situ X-ray photoelectron spectroscopy (XPS) and Density functional theory (DFT) calculations revealed that the interface of Cu/Cu 2 O facilitated electron transfer to N 2 , weakening the N N bond and lowering reaction barriers. This work demonstrated a synergistic photothermal-evaporation strategy for efficient nitrogen fixation, providing a sustainable pathway for overall nitrogen fixation in air.