CuO nanorods for high-efficiency nitrate electroreduction to ammonia

Electrocatalytic nitrate reduction (NO3−RR) provides an environmentally friendly alternative to the traditional Haber–Bosch technology for ammonia (NH3) production. Herein, cupric oxide (CuO) nanorods (NRs) were synthesized by a simple one-pot method and applied as NO3−RR electrocatalysts. Due to the nanorod-like structure and large specific surface area, the CuO NR electrocatalyst exhibited excellent NO3−RR performance. The electrocatalyst experienced in situ reconstruction and its phase partly changed from CuO to Cu/Cu2O in the process of the NO3−RR. The formed Cu/Cu2O/CuO mixed valence state promoted its catalytic activity for the NO3−RR. At −0.7 V potential, the faradaic efficiency and NH3 yield could reach 94% and 28.76 mg h−1 mgcat−1, respectively, along with excellent durability for 10 h.