Use of Rotating Ring‐Disk Electrodes to Investigate Graphene Nanoribbon Loadings for the Oxygen Reduction Reaction in Alkaline Medium. Issue 13 (15th May 2018)

• Record Type: Journal Article
• Authors: Cardoso, Eduardo S. F.; Fortunato, Guilherme V.; Maia, Gilberto
• Is Part Of: ChemElectroChem. Volume 5:Issue 13(2018)
• Page Start: 1691
• Page End: 1701
• Publication Date: 2018-05-15
• Subjects: alkaline medium -- electrocatalysis -- graphene -- oxygen reduction reaction -- supported catalyst; Electrochemistry -- Periodicals; 541.37
• DOI: 10.1002/celc.201800331
• Languages: English
• ISSNs: 2196-0216

Abstract

Abstract: The oxygen reduction reaction (ORR) is typically slow. Its kinetics, however, are influenced not only by the structure, nature, and doping of electrocatalysts, but also by the loadings of these materials, where all of these factors influence ORR selectivity to produce H2 O and/or H2 O2 . The loadings employed for graphene nanoribbon (GNR)‐modified glassy carbon (GC) electrodes and GC disk modified with commercial Pt (20 wt.%) on carbon (PtC) at 150 μg cm −2 (also resulting in electrode roughness) produced turbulence in the electrolyte flow, significantly changing the geometry of the rotating ring‐disk electrode (RRDE) and collection efficiency ( N ), as well as causing N to change with the rotation rate of the electrode. This effect toward the ORR was investigated with two analytical methods derived by Wu et al. and Zhou et al. A current deconvolution method for a better‐resolved Tafel analysis separating H O 2 - formation and reduction reactions resulted in more insightful understanding of the ORR responses provided by the RRDE for different GNR and PtC loadings. Abstract : Deconvolving oxygen reduction : graphene nanoribbon (GNR) loadings on glassy carbon disk electrodes are investigated as catalysts for oxygen reduction (ORR). Different loadings influence geometry of the disk electrode and the collection efficiency. While most values for ORR are similar among the modified electrodes; % H O 2 - rises with increasing electrode rotation rate. A deconvolution method is used to describe thicker, rougher catalyst layers via an insightful Tafel analysis.