Electrocatalytic Oxidation of Ammonia by (Salen)ruthenium(III) Ammine Complexes: Direct Evidence for a Ruthenium(VI) Nitrido Active Intermediate

• DOI: 10.1021/jacs.4c16902
• Publication Date: 2025-04-17T15:48:16Z
• Authors: Jianhui Xie; Tingting Yang; Longzhu Hong; Hui Li; Bing Li; Zhenguo Guo; Yingying Liu; Tai-Chu Lau

The electrocatalytic oxidation of ammonia using molecular catalysts has attracted much attention recently due to its potential for fuel cell applications. In this study, we report the (AO) by [RuIII(salchda)(NH3)(CH3CN)]+ (RuNH3, salchda = N,N'-bis(salicylidene)-o-cyclohexyldiamine dianion) and bromo derivative. Controlled electrolysis at 0.65 V versus Fc+/0 3.2 h a solution RuNH3 NH3 in CH3CN produced N2 with TON 26 Faradaic efficiency (FE) close 100%. was increased 79 147 when carried out 0.7 0.80 vs Fc+/0, respectively, FE maintained >99%, which are highest among ruthenium catalysts. An active intermediate detected shown be corresponding ruthenium(VI) nitrido complex [RuVI(salchda)(N)]+ (RuN) direct comparison an authentic sample RuN, have previously synthesized fully characterized. Direct kinetic studies on also been results consistent parallel electrophilic attack RuN bimolecular N···N coupling produce N2. DFT calculations performed support proposed mechanism.