Self-supported V-doped NiO electrocatalyst achieving a high ammonia yield of 30.55 μg h−1 cm−2 under ambient conditions

Abstract

To date, lots of efforts have been devoted to exploring an efficient route for N₂ fixation under ambient conditions. However, due to the high bond energy of the strong NN triple bond, it is still restricted by low NH₃ yield and conversion efficiency. Based on a previous concept of using carbohydrates as an accessory ingredient to form hollow metal oxides, here, we report V-doped NiO self-supported on nickel foam as an excellent NRR catalyst. Using glucose as a dispersant to disperse the surface of V-doped NiO, V/NiO with a disordered morphology reaches its highest NH₃ yield rate of 30.55 μg h⁻¹ cm⁻² at −0.3 V vs. reversible hydrogen electrode (RHE) and achieves a high faradaic efficiency (FE) of 11% at −0.1 V vs. RHE in 0.1 M KOH. Compared to NiO (5.32 μg h⁻¹ cm⁻²), V/NiO shows significantly improved NRR performance. Further, using ¹⁵N₂ as a supply gas gives strong evidence for the accurate detection of the generated NH₃ of V/NiO and N₂-TPD shows that V/NiO has stronger binding strength towards N₂, resulting in a splendid NH₃ yield rate.