Effect of Co Addition in Amorphous Ni-Based Alloys for the Alkaline Oxygen Evolution Reaction. (5th April 2018)

• Record Type: Journal Article
• Authors: Cole, Kevin M; Kirk, Donald W.; Thorpe, Steven J.
• Is Part Of: ECS transactions. Volume 85:Number 11(2018)
• Page Start: 91
• Page End: 103
• Publication Date: 2018-04-05
• Subjects: Electrochemistry -- Periodicals; Electrochemistry; Periodicals; Electronic journals; Electronic journal; 541.37
• DOI: 10.1149/08511.0091ecst
• Languages: English
• ISSNs: 1938-5862

Abstract

Abstract : An amorphous alloy Ni74.2 Co5 Nb12.5 Y8.3 was synthesized using cryogenic mechanical alloying and evaluated as a catalyst for the oxygen evolution reaction (OER) in alkaline media using cyclic voltammetry and Tafel measurements. Electrochemical testing showed that the amorphous alloy possessed a lower Tafel slope and enhanced kinetics for the OER compared to crystalline Ni and Ni95 Co5 . Anodic cycling of the amorphous alloy resulted in a lower onset potential for the OER and decreased Tafel values while no changes were observed for crystalline Ni95 Co5 . Pairing of in situ confocal Raman spectroscopy with anodic cycling showed that the amorphous alloy formed reversible hydrous Co oxy/hydroxides instead of irreversible CoO2 typically seen on crystalline NiCo alloys in KOH. The formation of hydrous Co oxy/hydroxides upon cycling was also accompanied by increased formation of β-NiOOH leading to enhanced catalytic performance of the amorphous alloy over the crystalline counterparts.