Urea Electro-Oxidation Reaction Enhancement via Magneto-Electrocatalysis on Nickel–Iron Oxide Nanoring Catalysts

• Published in: ACS applied energy materials 2024-10, Vol.7 (19), p.8526-8535
• Main Authors: Rodrigues, Eduardo Magalhães, Fernandes, Caio Machado, Alves, Odivaldo C., Santos, Evelyn C. S., Garcia, Flavio, Xing, Yutao, Ponzio, Eduardo Ariel, Silva, Júlio César M.
• Format: Article
• Language: English
• ISSN: 2574-0962; 2574-0962
• DOI: 10.1021/acsaem.4c01418

The application of magnetic fields has recently emerged as an advanced strategy to enhance electrocatalytic reactions. The influence of an alternate magnetic field (AMF) with amplitudes varying from 14.9 to 88.9 mT and frequency of 224 kHz in the urea electro-oxidation reaction (UER) on nickel nanoparticles (Ni), iron oxide magnetic nanorings (FeMNR), and Ni-FeMNR was investigated in this work. Transmission electron microscopy images showed iron oxide with the morphology of nanoring and nickel nanoparticles with an average diameter of about 3 nm. X-ray diffraction analysis showed characteristic peaks of magnetite, metallic nickel, and nickel oxide. Magnetization-field (M–H) curves recorded at 300 K showed that FeMNR and Ni-FeMNR present ferromagnetism or ferrimagnetism behavior. The results from chronoamperometric measurements showed that the AMF with amplitudes from 44.8 to 88.9 mT had a huge impact on the UER on the Ni-FeMNR catalyst, resulting in increases of obtained current in the process from 1.2 to 47%. An exponential dependence of the current from the UER and the AMF amplitude was observed. The substantial enhancement of the current obtained during the UER on Ni-FeMNR catalysts under the influence of the AMF can be mainly associated with the local heating generated that boosted the UER on nickel nanoparticles.