title: Composition-dependent electrocatalytic activity of palladium-iridium binary alloy nanoparticles supported on the multiwalled carbon nanotubes for the electro-oxidation of formic acid.
abstract: Surface-functionalized multiwalled carbon nanotubes (MWCNTs) supported Pd100-xIrx binary alloy nanoparticles (Pd100-xIrx/MWCNT) with tunable Pd/Ir atomic ratios were synthesized by a thermolytic process at varied ratios of bis(acetylacetonate) palladium(II) and iridium(III) 2,4-pentanedionate precursors and then applied as the electrocatalyst for the formic acid electro-oxidation. The X-ray diffraction pattern (XRD) and transmission electron microscope (TEM) analysis showed that the Pd100-xIrx alloy nanoparticles with the average size of 6.2 nm were uniformly dispersed on the MWCNTs and exhibited a single solid solution phase with a face-centered cubic structure. The electrocatalytic properties were evaluated through the cyclic voltammetry and chronoamperometry tests, and the results indicated that both the activity and stability of Pd100-xIrx/MWCNT were strongly dependent on the Pd/Ir atomic ratios: the best electrocatalytic performance in terms of onset potential, current density, and stability against CO poisoning was obtained for the Pd79Ir21/MWCNT. Moreover, compared with pure Pd nanoparticles supported on MWCNTs (Pd/MWCNT), the Pd79Ir21/MWCNT exhibited enhanced steady-state current density and higher stability, as well as maintained excellent electrocatalytic activity in high concentrated formic acid solution, which was attributed to the bifunctional effect through alloying Pd with transition metal.
authors.affiliation: State Key Laboratory of Chemical Resource Engineering, Beijing Key Laboratory of Electrochemical Process and Technology for Materials, Beijing University of Chemical Technology, Beijing 100029, P. R. China.
authors.forename: Jianming
authors.initials: J
authors.lastname: Bao
authors.affiliation: State Key Laboratory of Chemical Resource Engineering, Beijing Key Laboratory of Electrochemical Process and Technology for Materials, Beijing University of Chemical Technology, Beijing 100029, P. R. China.
authors.forename: Meiling
authors.initials: M
authors.lastname: Dou
authors.affiliation: State Key Laboratory of Chemical Resource Engineering, Beijing Key Laboratory of Electrochemical Process and Technology for Materials, Beijing University of Chemical Technology, Beijing 100029, P. R. China.
authors.forename: Haijing
authors.initials: H
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Chemical Resource Engineering, Beijing Key Laboratory of Electrochemical Process and Technology for Materials, Beijing University of Chemical Technology, Beijing 100029, P. R. China.
authors.forename: Feng
authors.initials: F
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Chemical Resource Engineering, Beijing Key Laboratory of Electrochemical Process and Technology for Materials, Beijing University of Chemical Technology, Beijing 100029, P. R. China.
authors.forename: Jingjun
authors.initials: J
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Chemical Resource Engineering, Beijing Key Laboratory of Electrochemical Process and Technology for Materials, Beijing University of Chemical Technology, Beijing 100029, P. R. China.
authors.forename: Zhilin
authors.initials: Z
authors.lastname: Li
authors.affiliation: State Key Laboratory of Chemical Resource Engineering, Beijing Key Laboratory of Electrochemical Process and Technology for Materials, Beijing University of Chemical Technology, Beijing 100029, P. R. China.
authors.forename: Jing
authors.initials: J
authors.lastname: Ji
keywords: bifunctional effect; composition-dependent; formic acid electro-oxidation; palladium iridium alloy; stability