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Exploration of electrodeposited platinum alloy catalysts for methanol electro-oxidation in 0.5�M H2SO4: Pt-Ni system
- Source :
- Journal of Solid State Electrochemistry. 8:968-975
- Publication Year :
- 2004
- Publisher :
- Springer Science and Business Media LLC, 2004.
-
Abstract
- In this work, we examine the electrocatalytic activity of electrodeposited Platinum (Pt)-Nickel (Ni) alloy layers on an inert substrate electrode for methanol oxidation reaction. Analyses using energy-dispersive fluorescent X-ray analysis and powder X-ray diffractometry confirm alloying of Pt with Ni in a range of compositions. Steady-state polarisation measurements in 0.5 M methanol+0.5 M H2SO4 solutions clearly show that the onset of electro-oxidation shifts to less anodic potential values (approximately 160 mV), while also exhibiting current enhancements up to ~15 times the currents obtained for the pure Pt electrodeposit. A linear relationship between the cyclic voltammetric peak (oxidation) current and [MeOH] is observed at a scan rate of 50 mVs−1, thus indicating reduced influence of adsorbed CO (COads) surface poison. A critical composition, Pt (92%)/Ni (8%) [denoted Pt-Ni(3) alloy] is found to exhibit maximum electrocatalytic activity, beyond which the activity drops, whereas pure Ni does not catalyse the reaction. While the promotion of electro-oxidation is understood to be largely due to the alloy catalyst, surface redox species of Ni oxide formed during the electro-oxidation process may also contribute to the oxygenation of COads, thereby enhancing the oxidation current. Plausible mechanisms of methanol oxidation on Pt/ transition metal alloy electrocatalysts are discussed in terms of electron transfer (in the alloy) and the role of Ni oxide species.
- Subjects :
- Materials science
Alloy
Inorganic chemistry
chemistry.chemical_element
engineering.material
Condensed Matter Physics
Electrochemistry
Redox
Catalysis
chemistry.chemical_compound
chemistry
Transition metal
engineering
General Materials Science
Methanol
Electrical and Electronic Engineering
Cyclic voltammetry
Platinum
Subjects
Details
- ISSN :
- 14330768 and 14328488
- Volume :
- 8
- Database :
- OpenAIRE
- Journal :
- Journal of Solid State Electrochemistry
- Accession number :
- edsair.doi...........f55984bbf948357baf4c4d91e19ebd24