Electrocatalytic reduction of hydroxylamine on copper immobilized platinum surface: Heterogeneous kinetics and sensing performance

• Published in: Electrochimica acta Vol. 318; pp. 486 - 495
• Main Authors: Hasnat, Mohammad A., Mumtarin, Zannatul, Rahman, Mohammed M.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 20.09.2019; Elsevier BV
• Subjects: Ammonia; Catalysis; Chemical reduction; Copper; Copper electrode; Electrodes; Electron transfer; Hydroxylamine; Intermetallic compounds; Kinetics; LOD; Platinum; Reaction kinetics; Selectivity; Sensor; Silver chloride; Voltammetry; LOD; Voltammetry; Hydroxylamine; Kinetics; Copper electrode; Sensor
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2019.06.058

A Cu electrode can reduce hydroxylamine (HA) in KCl solution but losses its activity very quickly. However, while Cu particles are immobilized on a Pt surface, the resultant electrode showed excellent catalytic activities towards HA reduction reactions compared to those shown by a Cu or Pt electrode. On the Pt-Cu surface, HA molecules involved two electron transfer reduction reaction yielding ammonia as an end product. The HA reduction process follows a first order kinetics on the Pt-Cu surface. In this study, heterogeneous electron transfer kinetics was studied to unveil the reduction pathway. It was observed that the reduction process occurs by a concerted mechanism having an intrinsic barrier of 0.24 eV. The formal potential of the reduction process was found to be −0.49 V with respect to Ag/AgCl (sat. KCl) reference electrode. The developed Pt-Cu electrode may be used as a HA sensor which exhibited a linear range from 5 to 110 μM HA with a limit of detection of 0.628 μM and good selectivity towards HA in water with recovery from 99 to 110%. [Display omitted]