A scenario for oxygen reduction in alkaline media. (August 2016)

• Record Type: Journal Article
• Authors: Ignaczak, Anna; Nazmutdinov, Renat; Goduljan, Aleksej; Moreira de Campos Pinto, Leandro; Juarez, Fernanda; Quaino, Paola; Santos, Elizabeth; Schmickler, Wolfgang
• Is Part Of: Nano energy. Volume 26(2016:Aug.)
• Page Start: 558
• Page End: 564
• Publication Date: 2016-08
• Subjects: Oxygen reduction -- Alkaline fuel cells -- Outer sphere electron transfer -- Oxygen-oxygen bond breaking; Nanoscience -- Periodicals; Nanotechnology -- Periodicals; Nanostructured materials -- Periodicals; Power resources -- Technological innovations -- Periodicals; Nanoscience; Nanostructured materials; Nanotechnology; Power resources -- Technological innovations; Periodicals; 621.042
• DOI: 10.1016/j.nanoen.2016.06.001
• Languages: English
• ISSNs: 2211-2855

Abstract

Abstract: We investigate oxygen reduction in alkaline solution with the focus on gold and silver electrodes. On the basis of theoretical considerations we propose a detailed mechanism, which we support by explicit calculations. In accordance with previous suggestions we conclude that the first step is an outer-sphere electron transfer to the oxygen molecule. The breaking of he oxygen-oxygen bond involves adsorption of OH on the electrode surface. This is much stronger on Au(100) than on Au(111), which explains why the former is a better catalyst. Abstract : Graphical abstract: Alkaline better than acid media? We suggest a mechanism for oxygen reduction in alkaline solution and explain, why this reaction does not require an expensive transition metal catalyst. Each step is supported by theoretical calculations based on DFT and on our own theory. In particular we investigate the breaking of the oxygen-oxygen bond on gold, and suggest a reason, why it breaks on Au(100), but not on Au(111). Abstract : Highlights: We suggest a complete mechanism for oxygen reduction in alkaline solutions. Each step is investigated by theoretical calculations. The rate-determining step takes place in the outer sphere mode. We explain why Au(100) is a better catalyst than Au(111).