Ag/Ti Electrodes for Electrochemical Nitrate Reduction: Revealing Highly Effective Interfaces by In‐Situ Electrochemical Mass Spectrometry

The electrochemical reduction of nitrate to hydroxyl amine or ammonia is a prominent means to effectively valorize agricultural effluent emissions. We demonstrate that bimetallic electrodes, composed of Ag nanoparticles deposited on Ti metal, exhibit a pronounced synergy in nitrate reduction in acidic electrolyte. This is evidenced by in‐situ electrochemical mass spectrometry (EC‐MS), showing NO evolution in a complex potential‐dependent profile at lower onset potentials compared to single metal Ag or Ti electrodes. Furthermore, liquid phase analysis shows a significant Faradaic efficiency to hydroxylamine for Ag/Ti electrodes, even at potentials above 0 V RHE , i.e., requiring at least a 200–300 mV lower overpotential than necessary for the single metal electrodes. We discuss favorable NO and hydroxylamine formation to be occurring on highly effective Ag/Ti interfaces. This work highlights the importance of interfaces and suggests that optimization of (Ag/Ti) bimetallic electrodes appears to be a valuable means to develop high performance electrodes for the reduction of nitrate in acidic conditions.