RhNi Bimetallenes with Lattice‐Compressed Rh Skin towards Ultrastable Acidic Nitrate Electroreduction

Harvesting recyclable ammonia (NH3) from acidic nitrate (NO3−)‐containing wastewater requires the utilization of corrosion‐resistant electrocatalytic materials with high activity and selectivity towards acidic electrochemical nitrate reduction (NO3ER). Herein, ultrathin RhNi bimetallenes with Rh‐skin‐type structure (RhNi@Rh BMLs) are fabricated towards acidic NO3ER. The Rh‐skin atoms on the surface of RhNi@Rh BMLs experience the lattice compression‐induced strain effect, resulting in shortened Rh–Rh bond and downshifted d‐band center. Experimental and theoretical calculation results corroborate that Rh‐skin atoms can inhibit NO2*/NH2* adsorption‐induced Rh dissolution, contributing to the exceptional electrocatalytic durability of RhNi@Rh BMLs (over 400 h) towards acidic NO3ER. RhNi@Rh BMLs also reveal an excellent catalytic performance, boasting a 98.4% NH3 Faradaic efficiency and a 13.4 mg h−1 mgcat−1 NH3 yield. Theoretical calculations reveal that compressive stress tunes the electronic structure of Rh skin atoms, which facilitates the reduction of NO* to NOH* in NO3ER. The practicality of RhNi@Rh BMLs has also been confirmed in an alkaline‐acidic hybrid zinc‐nitrate battery with a 1.39 V open circuit voltage and a 10.5 mW cm−2 power density. This work offers valuable insights into the nature of electrocatalyst deactivation behavior and guides the development of high‐efficiency corrosion‐resistant electrocatalysts for applications in energy and environment. RhNi bimetallenes with a Rh‐skin‐type structure (RhNi@Rh BMLs) can inhibit NO2*/NH2* adsorption‐induced Rh dissolution, contributing to the exceptional electrocatalytic durability for over 400 h towards acidic electrochemical nitrate reduction, which also reveals an excellent catalytic performance, including a high NH3 yield (13.4 mg h−1 mgcat−1) and a commendable NH3 Faradaic efficiency (98.4%).