Electrocatalysis of Sandwich-Structured Pd/Polypyrrole/Pd Composites toward Formic Acid Oxidation

Abstract

Palladium (Pd) nanoparticle catalysts were electrodeposited onto a graphite electrode by cyclic voltammetry (CV) technique from a 0.5 M HCl solution containing 0.2 M PdCl 2 , and then a film of polypyrrole (PPy) was immobilized onto the asprepared Pd-coated graphite electrode, leading to a PPy/Pd-coated electrode. Pd particles were repeatedly electrodeposited on the PPy/Pd-coated electrode to generate a Pd/PPy/Pd sandwich structured composite coated electrode. This developed composite electrode showed a satisfactory electrocatalysis toward the formic acid oxidation (FAO). The catalysis mechanism of the sandwich structured Pd/PPy/Pd composite catalyst toward FAO was also discussed on the basis of the obtained cyclic voltammograms and FT-IR spectra.

Recent Development of Pd-Based Electrocatalysts for Proton Exchange Membrane Fuel Cells

“…Meng et al [18,19] synthesized Pd single-crystal nanothorns along the <220> direction with a square wave electrochemical reduction method as shown in Figure 3. The nanothorn was made by a succession of epitaxic dodecahedrons of decreasing sizes aligned in the direction of the (111) plane and the growth of the thorn occurs along the (220) plane. Tian et al [20] obtained five fold twinned Pd nanorods with high-index facets of {hkk} or {hk0}.…”

“…Bai et al [110] supported Pd nanoparticles on polypyrrole-modified fullerene and the Pd/ppy-C60 catalyst showed a good electrocatalytic activity and stability for the oxidation of formic acid. Pd on polyaniline (Pd-PANI) nanofiber film [56], on polypyrrole (PPy) film [111] and PMo12 [112] showed excellent catalytic activity in the oxidation reaction of formic acid in acidic media. Qin et al [113] synthesized highly dispersed and active Pd/carbon nanofiber (Pd/CNF) catalyst which exhibited good catalytic activity and stability for the oxidation of formic acid.…”

Significant role of “burned” graphene in determining the morphology of LiNiO2 prepared under the air conditions

“…Nyquist curve, one kind of plots in Electrochemical Impedance Spectroscopy (EIS), can be employed directly to analyze the electrochemical reactions, such as the processes occurring at electrode/electrolyte interfaces and the lithium ion intercalation/ deintercalation process happening in the anode/cathode materials [29,30]. The Nyquist plots for all the prepared cells are illustrated in Fig.…”

Polypyrrole Composites: Electrochemical Synthesis, Characterizations and Applications

“…The enhanced electrocatalytic activities may be due to the uniform dispersion of nanoparticles in the PPy film and a synergistic effect of the highlydispersed metal particles so that the PPy film reduces electrode poisoning by adsorbed CO species (Selvaraj et al 2006). A Pd/PPy/Pd/G generated by sequential electrodeposition method (Ding et al, 2011) showed a satisfactory electrocatalysis toward the formic acid oxidation.…”