Enhanced nitrate reduction over functionalized Pd/Cu electrode with tunable conversion to nitrogen and sodium hydroxide recovery

Development of heteroatomic electrocatalysts with a particular geometric structure for wastewater denitrification remains a formidable challenge. Herein, we reported the fabrication of a series of PdCu electrodes with Pd electrodeposition times varying from 60 s to 360 s. Physiochemical and electrochemical techniques were used to analyze the structure, morphology and activity of as prepared catalytic electrodes. XRD data revealed the formation of a PdCu alloy, while a reduced particle sizes (ca. 5.3 nm) and a uniform distribution of Pd over Cu was demonstrated by TEM. The XPS measurement indicated the presence of redox (Pd0 and Cu+2) states hence demonstrating the formation of a PdCu alloy. A nitrate removal efficiency of ~98 %, N2 selectivity ~86 % with an alkali recovery of 335 mM was obtained over Pd/Cu 180 s at 0.68 mA cm−2. Enhanced nitrate reducibility and extended durability reveal the viability of a novel electrocatalytic and electrodialysis system for degrading NO3− in water, as well as a system for efficiently recovering liquid alkali.