Superaerophobic copper-based nanowires array for efficient nitrogen reduction

Electrocatalytic N₂ reduction reaction (NRR) provides a promising route for NH₃ production under ambient conditions to replace traditional Haber-Bosch process. For this purpose, efficient NRR electrocatalysts with high NH₃ yield rate and high Faradaic efficiency (FE) are required. Cu-based materials have been recognized catalytic active for some multi-electron-involved reduction reactions and usually exhibit inferior catalytic activities for hydrogen evolution reaction. We report here the preparation and characterization of a series of Cu-based nanowires array (NA) catalysts in situ grown on Cu foam (CF) substrate, including Cu(OH)₂ NA/CF, Cu₃N NA/CF, Cu₃P NA/CF, CuO NA/CF and Cu NA/CF, which are directly used as self-supported catalytic electrodes for NRR. The electrochemical results show that CuO NA/CF achieves a highest NH₃ yield rate of 1.84 × 10^-9 mol s^-1 cm^-2, whereas Cu NA/CF possesses a highest FE of 18.2% for NH₃ production at -0.1 V versus reversible hydrogen electrode in 0.1 M Na₂SO₄. Such catalytic performances are superior to most of recently reported metal-based NRR electrocatalysts. The contact angle measurements and the simulated calculations are carried out to reveal the important role of the superaerophobic NA surface structure for efficient NRR electrocatalysis.