Ethanol electro-oxidation on nanoworm-shaped Pd particles supported by nanographitic layers fabricated by electrophoretic deposition

Abstract

Different morphologies of nanographitic flake coatings used as catalyst supports for nanoworm-shaped palladium (Pd) were fabricated via the electrophoretic deposition (EPD) of dispersed nanographitic flakes in isopropyl alcohol. Various concentrations of magnesium nitrate hexahydrate (MNH) were used as an additive binder in the EPD process. After that palladium nanoworms were deposited by a direct sputtering on the fabricated nanographitic flake coatings. It was observed that the variation of the MNH concentration has a remarkable influence on the flake packing density of the deposited coatings and the adhesion between the nanographitic flakes and indium tin oxide (ITO) coated glass plates, thus offering a control of the aggregation of the nanographitic flakes. The morphology change of the coatings caused by MNH, which can either improve or weaken the conductivity of the fabricated coatings, has an important role in determining the performance of the Pd-sputtered samples for ethanol electrooxidation. The sample obtained with 1 mg mL À1 of MNH exhibited a high electrocatalytic activity and stability due to a high flake packing density and strong adhesion between the nanographitic flakes and ITO, and retained planar morphology of the nanographitic flakes during the EPD. Fig. 14 Nyquist plots of EIS for Pd/0.25MgO-NGr/ITO, Pd/0.5MgO-NGr/ITO, Pd/1MgO-NGr/ITO and Pd/2MgO-NGr/ITO at À0.2 V (vs. Ag/AgCl) in 0.5 M NaOH with 1 M ethanol. The inset is the equivalent circuit used to interpret the impedance spectra of the four samples.This journal is

PdAg/CNT catalyzed alcohol oxidation reaction for high-performance anion exchange membrane direct alcohol fuel cell (alcohol = methanol, ethanol, ethylene glycol and glycerol)

“…One method of reducing the cost of catalyst layer is to lower down the loading of Pt, while another method is to replace Pt with more abundant and less expensive Pd. To prepare highly active Pd-based catalysts, a number of strategies have been investigated, including controlling the morphology of Pd [15][16][17][18][19], alloying other elements to prepare Pd-M catalyst [20][21][22][23][24][25], and improving the surface area of the catalyst support [26][27][28].…”

Single-Step Electrophoretic Deposition of Non-noble Metal Catalyst Layer with Low Onset Voltage for Ethanol Electro-oxidation

“…All the XRD peaks of the fabricated catalyst layers belong to the characterized peaks of the as-received ITO, except for the peak at 26.56°belonging to the (002) plane of the nanographitic flakes. 11,30 No shift in the XRD peaks of ITO upon annealing was found, thus confirming the stability of the ITO layer to the heating treatment. There are no noticeable XRD peaks for MgO or MgO x because the amount of crystalline MgO or MgO x was too small to be detected, which has been reported in our previous work.…”

Triple phase boundary and power density enhancement in PEMFCs of a Pt/C electrode with double catalyst layers

“…17 The colloidal EPD process is consisted of two main stages, in which charged particles in colloidal solution move toward an electrode with opposite charge under an applied electric eld, and then deposit onto the surface of substrate. The EPD presents relatively short processing times, good uniformity, and adequate control of deposit thickness onto the surface of electrode, 18,19 as well as making sure that the catalysts are well attached to the conductive substrates. Especially, the Pt catalysts can easily be located near the surface of electrodes by using the EPD method.…”