Quantitative Operando Detection of Electro Synthesized Ammonia Using Mass Spectrometry
A chip-based EC-MS setup with 22 eV selective ionisation enables operando ammonia detection down to a few pmol s⁻¹ in both aqueous and non-aqueous electrolytes. Faradaic efficiency of 49±3% is demonstrated at ambient pressure, and continued ammonia production after lithium electroplating termination is observed — offering a mechanistic explanation for efficiency gains seen under dynamic cycling conditions.