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Evaluating Copper-Modified Carbon Composite Nanofiber Electrodes for Electrocatalytic Nitrate Reduction

Year: 2025

Type: article

Abstract: High Resolution Image Download MS PowerPoint Slide The increasing urgency to address nitrate (NO 3 – ) pollution in water sources has intensified research on electrochemical nitrate reduction, a process capable of transforming NO 3 – into valuable ammonia (NH 3 ) by using renewable electricity. Copper (Cu) catalysts can reduce NO 3 –, but their activity and selectivity toward NH 3 can vary based on their structure, reaction environment, and support material. This study examines the efficacy of Cu-modified carbon nanofiber (CNF) supports, tailored through electrospinning, in enhancing the electrocatalytic reduction of NO 3 – to NH 3 . Three variants of CNF supports were synthesized: pristine CNFs, CNFs integrated with carbon nanotubes (CNF/CNTs), and CNFs embedded with titanium dioxide nanoparticles (CNF/TiO 2 ). Each electrode’s physical and electrochemical properties were analyzed before and after Cu electrodeposition. Notably, the CNF/TiO 2 /Cu composites demonstrated a selectivity exceeding 40% for the conversion of NO 3 – to NH 3 at neutral pH─significantly outperforming the CNF/CNT/Cu (<5%) and CNF/Cu (20%) configurations when deposited with equivalent amounts of Cu. The CNF/TiO 2 /Cu electrode also exhibited consistent and stable performance over the extended experimental duration (| Q | = 70 C), maintaining NH 3 selectivity rates of over 50%. Tafel analysis and operando Raman spectroscopy suggest that TiO 2 plays an active role in hydrogenating nitrogenous reduction products for enhanced selectivity. This research highlights the importance of electrode-catalyst selection in electrochemical NO 3 – reduction and identifies TiO 2 -containing electrodes as promising solutions in this domain.

Source: ACS Applied Engineering Materials

DOI: 10.1021/acsaenm.5c00510