Ru─B Modulated Electronic Structure Promotes Electrocatalytic Nitrate Reduction to Ammonia and Zinc‐Nitrate Battery

Ru‐based materials exhibit outstanding potential for electrocatalytic nitrate reduction reactions (eNitRR), but balancing catalytic activity and selectivity remains a challenge. Here, boron clusters ( closo ‐[B 12 H 12 ] 2− ) serve as both reducing agent and boron source, and boron cage collapses during the reduction, releasing B atoms for doping. Ru is dispersed into independent atoms and stabilized by abundant boron to form Ru─B/Cu x O. Crucially, electron deficiency within boron in the formed Ru─B bonds draws electron density from Ru 0 , generating electron‐deficient Ru δ+ sites, which significantly boosts eNitRR activity. Density functional theory (DFT) calculations confirm the altered electronic structure of Ru by boron doping. This modification promotes the generation of crucial * H intermediates, enhances the adsorption and activation of NO 3 − , and facilitates the dissociation of NH 3 on the catalyst surface. Consequently, Ru─B/Cu x O delivers a maximum NH 3 yield rate of 70.36 g h −1 g cat. −1 and Faradaic efficiency of 98.45%. Furthermore, a Zn‐NO 3 − battery assembled with the Ru─B/Cu x O cathode demonstrates a high open‐circuit voltage of 1.62 V and an impressive output power density of 1.46 mW cm −2 . This study uniquely harnesses dual‐functional boron clusters as structural bridges to construct boron‐doped ruthenium complexes, effectively regulating ruthenium's electronic structure. It provides novel strategies and insights for developing high‐performance ruthenium‐based eNitRR catalysts.