title: Carbon-Nanotubes-Supported Pd Nanoparticles for Alcohol Oxidations in Fuel Cells: Effect of Number of Nanotube Walls on Activity.
abstract: Carbon nanotubes (CNTs) are well known electrocatalyst supports due to their high electrical conductivity, structural stability, and high surface area. Here, we demonstrate that the number of inner tubes or walls of CNTs also have a significant promotion effect on the activity of supported Pd nanoparticles (NPs) for alcohol oxidation reactions of direct alcohol fuel cells (DAFCs). Pd NPs with similar particle size (2.1-2.8 nm) were uniformly assembled on CNTs with different number of walls. The results indicate that Pd NPs supported on triple-walled CNTs (TWNTs) have the highest mass activity and stability for methanol, ethanol, and ethylene glycol oxidation reactions, as compared to Pd NPs supported on single-walled and multi-walled CNTs. Such a specific promotion effect of TWNTs on the electrocatalytic activity of Pd NPs is not related to the contribution of metal impurities in CNTs, oxygen-functional groups of CNTs or surface area of CNTs and Pd NPs. A facile charge transfer mechanism via electron tunneling between the outer wall and inner tubes of CNTs under electrochemical driving force is proposed for the significant promotion effect of TWNTs for the alcohol oxidation reactions in alkaline solutions.
authors.affiliation: Fuels and Energy Technology Institute & Department of Chemical Engineering, Curtin University, Perth, WA 6102 (Australia).
authors.forename: Jin
authors.initials: J
authors.lastname: Zhang
authors.affiliation: School of Chemistry and Environment, Beihang University, Beijing 100191 (PR China).
authors.forename: Shanfu
authors.initials: S
authors.lastname: Lu
authors.affiliation: School of Chemistry and Environment, Beihang University, Beijing 100191 (PR China).
authors.forename: Yan
authors.initials: Y
authors.lastname: Xiang
authors.affiliation: Collaboarative Innovation Center of Sustainable Energy Materials, Guangxi University, Nanning 530004 (PR China).
authors.forename: Pei Kang
authors.initials: PK
authors.lastname: Shen
authors.affiliation: Fuels and Energy Technology Institute & Department of Chemical Engineering, Curtin University, Perth, WA 6102 (Australia).
authors.forename: Jian
authors.initials: J
authors.lastname: Liu
authors.affiliation: Fuels and Energy Technology Institute & Department of Chemical Engineering, Curtin University, Perth, WA 6102 (Australia). s.jiang@curtin.edu.au.
authors.forename: San Ping
authors.initials: SP
authors.lastname: Jiang
mesh_terms: D000438:Alcohols / Q000737:chemistry*; D053768:Metal Nanoparticles; D046529:Microscopy, Electron, Transmission; D037742:Nanotubes, Carbon; D010084:Oxidation-Reduction; D010165:Palladium / Q000737:chemistry*; D013059:Spectrum Analysis, Raman
chemical_list: D000438:Alcohols; D037742:Nanotubes, Carbon; D010165:Palladium
keywords: Pd nanoparticles; alcohol oxidations; carbon nanotubes; electron tunneling effect; volcano curves