Spontaneous reduction of palladium chloride on surface of carbon materials to produce electrochemical catalysts for ethanol oxidation

Pd nanoparticles (Pd-NPs) were deposited on the surface of Vulcan XC-72 carbon black (CB), multi-walled carbon nanotubes (MWCNTs) and carbon spheres (CSs) by the spontaneous reduction of PdCl₂ with oxygen-functional groups on the carbon surfaces to produce catalysts for the electrochemical oxidation of ethanol. These carbons were also modified with a cationic surfactant (hexadecyltrimethyl ammonium bromide, CTAB) and subsequently used as supports for the deposition of Pd nanoparticles using the spontaneous reduction method. SEM, TEM and XRD were used to characterize their structures. Pd-NPs with a size of ca. 9 nm were obtained on the surface of the CTAB-modified MWCNTs. The amount of Pd-NPs spontaneously deposited on the CTAB-MWCNTs is much larger than that on the MWCNTs, CB or CSs. The Pd/CTAB-MWCNTs exhibit a higher anodic peak current density of 44.2 mA·cm^-2 in cyclic voltammetry, indicating a better electrocatalytic activity for ethanol oxidation than the other catalysts.