Core-Shell Pd9Ru@Pt on Functionalized Graphene for Methanol Electrooxidation. Issue 7 (1st January 2018)

• Record Type: Journal Article
• Authors: Kuo, Chih-Chia; Chou, Shih-Cheng; Chang, Yu-Chen; Hsieh, Yi-Chieh; Wu, Pu-Wei; Wu, Wen-Wei
• Is Part Of: Journal of the Electrochemical Society. Volume 165:Issue 7(2018)
• Page Start: H365
• Page End: H373
• Publication Date: 2018-01-01
• Subjects: Core-Shell -- Functionalized Graphene -- Methanol Electro-oxidation; Electrochemistry -- Periodicals; 541.3705
• DOI: 10.1149/2.0781807jes
• Languages: English
• ISSNs: 0013-4651

Abstract

Abstract : A simple but effective electrochemical route to functionalize graphene is demonstrated. Cyclic voltammetric sweeps (CV) are performed in a 0.5 M H2 SO4 aqueous solution on electrodes consisting of carbon cloth, graphene, and Nafion ionomer. Upon exposure to ambient oxygen, the formation of hydroxyl radicals from the oxygen reduction reaction during the CV cycles initiates the decomposition of the Nafion ionomer, which produces oxygenated functional groups on the graphene surface. Using contact angle measurements and X-ray photoelectron spectroscopy, various amounts of Nafion ionomer are explored to determine the optimum conditions for graphene functionalization. Afterwards, Pd9 Ru nanoparticles with an average size of 3–4 nm are synthesized and impregnated on functionalized graphene (FGN). To prepare core-shell electrocatalysts, Pd9 Ru/FGN is subjected to Cu underpotential deposition followed by a galvanic displacement reaction to deposit a Pt monolayer on the Pd9 Ru surface (Pd9 Ru@Pt). The as-synthesized sample (Pd9 Ru@Pt/FGN) exhibits enhanced performance in methanol electrooxidation, which includes a better activity and lower susceptibility to poisoning by intermediates. The electrochemically active surface area (ECSA) of Pd9 Ru@Pt/FGN shows a value that is 1.5-fold larger than that of Pd9 Ru@Pt on untreated graphene (Pd9 Ru@Pt/GN). In the durability tests, Pd9 Ru@Pt/FGN and Pd9 Ru@Pt/GN demonstrate losses in the ECSA of 14.9% and 30.3%, respectively.