High Performance Pd, PdNi, PdSn and PdSnNi Nanocatalysts Supported on Carbon Nanotubes for Electrooxidation of C2-C4 Alcohols

摘要

Nanocatalysts Pd, Pd8Ni2, Pd8Sn2 and Pd8Sn1Ni1 supported on multi-walled carbon nanotubes (MWCNTs) were successively synthesized by the chemical reduction method in the glycol-water mixture solvent. Transmission electron microscopy results show that the prepared Pd, Pd8Ni2, Pd8Sn2 and Pd8Sn1Ni1 nanoparticles are uniformly dispersed on the surface of MWCNTs. The average particle sizes of the nanocatalysts are 3.5-3.8 nm. Electroactivity of the prepared catalysts towards oxidation of ethanol, 1-propanol, 2-propanol, n-butanol, iso-butanol and secbutanol (C2-C4 alcohols) in alkaline medium was studied by cyclic voltammetry and chronoamperometry. The current density obtained for the electrooxidation of C2-C4 alcohols depends on the catalysts and the various structures of the alcohols. Addition of Sn or/and Ni to Pd nanoparticles enhances the electroactivity of the Pd/MWCNT catalyst. Furthermore, the ternary Pd8Sn1Ni1/MWCNT catalyst presents the highest electroactivity for the oxidation of C2-C4 alcohols among the prepared catalysts. Electrocatalytic activity order among propanol isomers and butanol isomers is as follows respectively: 1-propanol > 2-propanol, and n-butanol > iso-butanol > sec-butanol > tert-butanol. This is consistent with the Mulliken charge value of the carbon atom bonded with hydroxyl group in the corresponding alcohol molecule.