A Hydrogen‐Nitric Oxide Cell for the Synthesis of Hydroxylamine

A ‐NO fuel cell was designed for the synthesis of hydroxylamine in the gas phase. The hydroxylamine produced was trapped in an aqueous solution of held in a silica‐wool disk used as an electrolyte barrier for and NO. Among the cathode electrocatalysts tested, iron‐phthalocyanine (Fe‐Pc) impregnated in graphite was the most favorable one for selective synthesis of hydroxylamine. Active carbon and carbon whiskers used to support the Fe‐Pc enhanced the formation of hydroxylamine remarkably. The carbon itself slightly catalyzed the formation of and . Excluding the effects of the support, Fe‐Pc catalyzed the electrochemical synthesis of hydroxylamine with high selectivity (≈100%). Applied voltage across the cell did not appreciably enhance the formation of hydroxylamine. The reaction under short‐circuit conditions was most favorable for the synthesis of hydroxylamine. It is suggested that the reduction of NO occurs on the site of Fe‐Pc with protons and electrons transferred from the anode. The very selective synthesis of hydroxy‐lamine over Fe‐Pc must be ascribed to an site isolated by phthalocyanine ring. This isolation prohibits both the formation of through the intramolecular elimination of from the adjacent NHO intermediates and the formation of and through the breaking of N‒O bonds.