Enhanced electrochemical nitrate reduction: Geometrically tailored Pd/Cu electrodes for superior nitrogen selectivity

Electrochemical nitrate reduction (ENR) offers a promising way to remove harmful nitrogen pollutants from wastewater. In this study, we prepared Pd/Cu electrocatalysts by electrodepositing palladium onto copper foam, creating nanoparticles that provide plenty of active sites for nitrate adsorption and improve ENR performance. Electrochemical tests like Cyclic Voltammetry (CV), Linear Sweep Voltammetry (LSV), chronoamperometry (CA), and Ion Chromatography (IC) helped evaluate their activity. The Pd/Cu5m catalyst showed impressive results, removing 98.83% of nitrate and maintaining a current density of 1.36mA/cm2 over 8h. Remarkably, the conversion of nitrate to nitrogen gas (N2) was highly selective at 98.72%, meaning almost all nitrate was turned into harmless nitrogen. When combined with an electrodialysis system, the alkali concentration increased significantly, indicating potential for integrated wastewater treatment. Additionally, the Pd/Cu5m catalyst proved stable over multiple testing cycles. These findings demonstrate that Pd/Cu bimetallic electrocatalysts are effective and durable for selective nitrate removal from wastewater using ENR.