Pd-Based Bimetallic and Trimetallic Catalyst for Direct Formic Acid Fuel Cells

Abstract

The annealing process effect on the activity of Pd/C, PdCu/C alloy, PdNi/C alloy, and the physical mixture of PdCu/C and PdNi/C alloys are studied. These Pd-based bimetallic catalysts are synthesized via a metal-salt reduction reaction. CV results indicate that the non-annealed Pd-based catalysts show similar surface structure and less electrochemical activity towards formic acid oxidation than the annealed samples in the following order: Pd/

Electrochemical Dealloying-Assisted Surface-Engineered Pd-Based Bifunctional Electrocatalyst for Formic Acid Oxidation and Oxygen Reduction

“…The voltammetric profile of the dealloyed catalysts in 0.5 M H 2 SO 4 shows the characteristic signature for Pd (Figures A and S11A). A close inspection of the voltammetric profile reveals that (i) the potential corresponding to surface oxide reduction ( E @Pd–O) on the Co 0.02 Cu 13.8 Pd 86.18 surface is more positive than the other two catalysts, (ii) Co 0.55 Cu 24.4 Pd 75.05 and Co 0.2 Cu 4.6 Pd 95.2 catalysts show two anodic peaks in the low-potential region, which can be assigned for the removal of adsorbed hydrogen on (111) and (100) plane of Pd active site, , whereas Co 0.02 Cu 13.8 Pd 86.18 shows a single peak corresponding to the hydrogen desorption from Pd(100) and (iii) two anodic peaks were observed at high positive potential for the oxidation of Pd(100) and Pd(111) surface planes at 0.95 and 1.1 V, respectively. This positive shift in the E @Pd–O for Co 0.02 Cu 13.8 Pd 86.18 catalyst suggests the decreased oxophilicity as well as weakly bonded oxygenated species (OH ad , OOH ad , CO ad ) to Pd surface. , Such positive shift can be accounted for the crystal facets, oxophilicity, and associated geometric and electronic effects.…”