Nitrogen containing carbon spheres as an efficient electrocatalyst for oxygen reduction: Microelectrochemical investigation and visualization. Issue 37 (14th September 2017)

• Record Type: Journal Article
• Authors: Tiwari, Aarti; Singh, Vikram; Mandal, Debaprasad; Nagaiah, Tharamani C.
• Is Part Of: Journal of materials chemistry. Volume 5:Issue 37(2017)
• Page Start: 20014
• Page End: 20023
• Publication Date: 2017-09-14
• Subjects: Materials -- Research -- Periodicals; Chemistry, Analytic -- Periodicals; Environmental sciences -- Research -- Periodicals; 543.0284
• DOI: 10.1039/c7ta05503j
• Languages: English
• ISSNs: 2050-7488

Abstract

Abstract : A fast-scanning ultramicroelectrode probe is employed to trace the mechanistic pathway followed by the designed nitrogen containing carbon spheres in highly alkaline medium. Abstract : The oxygen reduction reaction (ORR) in low temperature fuel cells limits the obtainable output triggering the necessity of screening the employable catalysts precisely. A nitrogen-containing carbon sphere (NCS) catalyst was synthesized using a soft template and was studied for the oxygen reduction reaction. The NCS catalyst was shown to have superior activity with an onset potential of 0.985 V ( vs. RHE) and a diffusion-limited current density of 6.16 mA cm −2 . The kinetic insight from the rotating disk electrode (RDE) and rotating ring-disk electrode (RRDE) revealed an overall 4e − reduction by a (2 + 2) electron pathway with a rate constant of 4.6 × 10 −4 cm s −1 at the onset potential. A fast screening of the localized electrochemical activity using sample generation-tip collection (SG-TC) in combination with a chronoamperometric multiple pulse technique was applied in the present study to trace the formation, evolution and conversion of intermediate species using a Pt ultramicroelectrode. The local catalytic activity of the NCS catalyst was successfully visualized by scanning electrochemical microscopy (SECM) in highly alkaline medium.