Electro-reduction of nitrate to ammonia (e-NRA) has been considered as a facile and promising approach to eliminate nitrate pollution and produce ammonia (NH3) under ambient conditions. Nevertheless, in recent state-of-the-art...

The oxygen evolution reaction (OER), oxygen reduction reaction (ORR), and hydrogen evolution reaction (HER) all have attracted much attention due to their utmost importance for clean and renewable energy applications....

Cheap and highly efficient electrocatalysts are needed to expedite the sluggish oxygen evolution reaction (OER) in water electrolysis to provide clean and sustainable hydrogen energy. In this work, systematic first-principles...

Ruthenium (Ru) has been proved to be a viable alternative to platinum (Pt) for hydrogen evolution reaction (HER). However, it is still highly desirable to further raise the efficiency and...

Electrochemical reduction reaction of nitrate (NITRR) provides a sustainable route toward the green synthesis of ammonia. Nevertheless, it remains challenging to achieve high‐performance electrocatalysts for NITRR especially at low overpotentials. In this work, hierarchical nanospheres consisting of polycrystalline Iridium&copper (Ir&Cu) and amorphous Cu2O (CuxIryOz NS) have been fabricated. The optimal species Cu0.86Ir0.14Oz delivers excellent catalytic performance with a desirable NH3 yield rate (YR) up to 0.423 mmol h−1 cm−2 (or 4.8 mg h−1 mgcat−1) and a high NH3 Faradaic efficiency (FE) over 90% at a low overpotential of 0.69 V (or 0 VRHE), where hydrogen evolution reaction (HER) is almost negligible. The electrolyzer toward NITRR and hydrazine oxidation (HzOR) is constructed for the first time with an electrode pair of Cu0.86Ir0.14Oz//Cu0.86Ir0.14Oz, yielding a high energy efficiency (EE) up to 87%. Density functional theory (DFT) calculations demonstrate that the dispersed Ir atom provides active site that not only promotes the NO3− adsorption but also modulates the H adsorption/desorption to facilitate the proton supply for the hydrogenation of *N, hence boosting the NITRR. This work thus points to the importance of both morphological/structural and compositional engineering for achieving the highly efficient catalysts toward NITRR.