SUMMARY

Nitrate is the world’s most widespread surface and ground water contaminant that causes adverse effects on human health such as methemoglobinemia (“blue baby syndrome”) and cancer. Most abiotic nitrate removal strategies center on the use of ion exchange resins. Ion exchange resins are effective, yet are not sustainable the process generates a large amount of waste. Biological approaches are inapplicable for removal of high nitrate ions and large scale applications as well as possibility of bacterial contamination in the drinking water. Electrocatalytic nitrate remediation; however, is one emerging approach for nitrate removal which does not produce waste as nitrate is converted directly to inert nitrogen gas. The main challenge with electrocatalytic nitrate reduction is the low nitrate conversion yield, poor nitrogen selectivity, and no data for long-term operations. The production of equally harmful contaminant intermediate species such as nitrite and ammonium, has also limited the applicability of electrochemical routes for nitrate remediation. Electrocatalytic nitrate valorization is another emerging approach for nitrate removal. Here, nitrate is converted directly to ammonium. The main challenge with valorization of nitrate is the low activity and selectivity of the nitrate to ammonium, and the structure sensitivity studies are insufficient. Here, we propose to investigate the electrocatalytic properties of palladium (Pd) and copper (Cu) which contains structured surfaces. The primary aim is to identify which facets are highly active and selective for nitrate and nitrite reduction. Engineering the structure of Pd and Cu that enhances the nitrate removal efficiency and enables to steer the selectivity toward nitrogen and ammonium. To achieve the real-life applications, we also verify the long-term operations for the developed electrocatalysts and demonstrate the origin of superior stability.