Efficient Synthesis of Hydroxylamine via Nitrate Electroreduction on Sulfate/Oxide‐Derived Lead Catalysts

ABSTRACT Hydroxylamine (NH 2 OH) is a crucial chemical in various industries, yet its conventional synthesis methods are energy‐intensive and environmentally harmful. In this study, we present a sulfate/oxide‐derived lead (SOD‐Pb) electrocatalyst, fabricated through a stepwise electrode anodization and reduction technique, for the electrochemical synthesis of hydroxylamine via nitrate reduction. The SOD‐Pb electrode exhibits remarkable catalytic activity, achieving a Faradaic efficiency (FE) exceeding 80% within a potential range of –0.4 to –1.0 V, with a partial current density reaching –129 mA cm − 2 at –1.2 V in acidic conditions. Furthermore, its catalytic activity for NH 2 OH conversion is regenerated via in situ electrode reduction, which reverses PbSO 4 passivation during controlled current electrolyses by reforming an active SOD‐Pb‐like surface. The process also allows for the direct recovery of hydroxylammonium sulfate ((NH 3 OH) 2 SO 4 ) as a purified crystalline solid from the electrolyte via crystallization‐based separation, demonstrating its practical applicability. This work introduces a scalable, sustainable method for hydroxylamine production, offering a cleaner alternative to traditional processes by integrating efficient electrochemical conversion with nitrate waste remediation.