Mode of electrochemical deposition on the structure and morphology of bimetallic electrodes and its effect on nitrate reduction toward nitrogen selectivity

This work investigates the effect of electrode preparation on nitrate reduction reaction with a focus on increasing nitrogen yield. Results indicated that stainless steel (SS) supported tin-palladium (SS/Sn-Pd) electrodes synthesized via multi-step electrodeposition at low voltage (<10 V) substantially influenced the performance of nitrate transformation and nitrogen selectivity. Different electrodeposition programs, in terms of charging step and batch of metal solution, affected the crystallite size and surface morphology, i.e., roughness, and thus impacted nitrate reduction capability. Of the most significance, electrode prepared with one batch of solution containing both SnCl₂ and PdCl₂ at molar ratio of 4 to 1 exhibited the best performance in nearly 100% nitrate reduction and 81% nitrogen yield. The proposed low voltage electrochemical deposition process enables a new route to control the reactivity and selectivity of the reduction of oxyanions such as nitrate in water by manipulating electrode surface morphology.