Electrochemical Co-Production of Ammonia and Biodegradable Polymer Monomer Glycolic Acid via the Co-Electrolysis of Nitrate Wastewater and Waste Plastic

Electrochemical reformation of nitrate wastewater andpoly(ethyleneterephthalate) (PET) plastic waste into ammonia (NH3) andfine chemicals is a sustainable strategy for waste resource utilization.Herein, a co-production system of ammonia and glycolic acid (GA, degradablepolymer monomer) is constructed by coupling nitrate reduction andethylene glycol (EG, in PET hydrolysate) oxidation. Low-crystallineCoOOH (LC-CoOOH/CF) and Pd nanothorns (Pd NTs/NF) grown in situ onthe metal foam substrates are employed as cathode and anode, respectively.The high density of amorphous regions in LC-CoOOH/CF enables enhancednitrate adsorption and provides abundant active sites, ultimatelyleading to an ammonia Faradic efficiency (FE) of 97.38 & PLUSMN; 1.0%at -0.25 V vs reversible hydrogen electrode (RHE). Meanwhile,the unique nanothorn morphology endows the Pd NTs/NF with a high-curvaturetip, triggering a tip effect (TE) to promote the highly selectiveoxidation of EG to GA. Furthermore, in the two-electrode couplingsystem, the co-production of NH3 and GA is operated ata low energy consumption (onset voltage: 0.5 V), much lower than thetraditional nitrate electrolysis process (1.4 V). This study providesa method for the resource utilization of nitrate wastewater and PETplastic waste to co-produce NH3 and value-added chemicals.