Coupling ZnN₄ Atomic Sites with Graphitic Nitrogen for Enhanced Ammonium Production via Electrocatalytic Nitrate Reduction

Abstract The electrocatalytic nitrate reduction reaction (NO₃RR) presents a promising alternative to the traditional Haber‐Bosch process for synthesizing ammonium (NH₃) under mild conditions. Supported single atoms have emerged as active catalysts for this conversion; however, the efficiency of NH₃ production are limited by the modest activity and selectivity of these catalysts. In this study, it is demonstrated that zinc single atoms supported on nitrogen‐doped carbon (ZnNCs), derived from zeolitic imidazolate framework‐8 (ZIF‐8), possess remarkable catalytic performance for this conversion, achieving an unprecedented selectivity (exceeding 90%) for NH₃ formation across a broad potential range (−0.4–−0.8 V vs. RHE). Comprehensive analyses reveal that the incorporation of a graphitic nitrogen atom adjacent to the Zn‐N₄ site precisely modulates the reaction pathway, enabling a unique dual‐site adsorption and cascading reaction route for NH₃ formation. These findings not only uncover a novel reaction mechanism for the NO₃RR but also have the potential to inspire the development of more efficient NO₃RR catalysts.