Co‐Catalytic Metal‐Support Interactions Design on Single‐Atom Alloy for Boosted Electro‐Reduction of Nitrate to Nitrogen

Abstract The past decades have seen considerable imbalances in the nitrogen cycle due to the excessive use of nitrate in agriculture and industry. Electrocatalytic reduction of nitrate (NO 3 RR) to nitrogen (N 2 ) holds significant potential for addressing nitrate pollution in wastewater but suffers from nitrite formation and the sluggish hydrogeneration process. Here a single atom alloy (SAA) catalyst featuring atomically dispersed Ru on 2D Ni metal (Ru 1 Ni), proving remarkable nitrate reduction performance (NO 3 − –N conversion (≈93%) and N 2 selectivity (≈99%)) through the co‐catalytic metal‐support interactions (CMSI) effect is reported. Significantly, the Ru 1 Ni SAA achieves NO 3 RR removal capacity as high as 11.1 mg L −1 h −1 cm −2 with 20 cycles stability (9 h per cycle), surpassing most previously reported works. The core of the boosting lies in the synergistically promoted nitrate activation and accelerated hydrogenation of nitrogen oxide intermediates on the Ru site and Ni substrate, respectively, revealed by various in situ experiments and theoretical simulations. DFT calculations indicate electron transfer from substrate Ni to Ru and more robust interaction between NO 3 − and Ru–Ni in comparison to that of Ni–Ni. This work offers a resilient methodology for the rational design of highly efficient electrocatalysts with CMSI modulation for NO 3 RR, illuminating the arena of wastewater treatment and the nitrogen cycle.