Effect of Au Content in Aupd Electro-Synthesized Mixtures Toward Formic Acid/Formate Electro-Oxidation

AuPd mixtures were electrochemically synthesized using pulse potential techniques such as differential pulse amperometry, square wave voltammetry and second harmonic AC voltammetry in order to modify the metal content of the mixtures. Pure Au and Pd were electrochemical synthesized for comparison purposes. The metal proportions of 90:10, 60:40, 50:50, 35:65 and 15:85 Au-Pd were obtained according to EDS and XRF analyses.  Formic acid/formate was worked in 0.3 M KOH (as electrolyte) in order to preserve the presence of formate. At low Formic acid/formate concentration (0.01 and 0.1 M) pure-Pd material exhibited good electrocatalytic activity in terms of current density. Pure-Au material showed no response for formic acid/formate electrooxidation at low concentrations. On the other hand, AuPd mixtures exhibited different behavior as function of the bimetallic content. At low concentrations (0.01 and 0.1 M) mixtures enriched with Au exhibited a poor electrocatalytic activity. Meanwhile,  Pd-enriched mixtures content showed low current density than pure-Pd. However, when the formic acid concentration was increase to 0.3 and 0.5 M, pure-Pd showed higher CO-poisoning effect than Pd-enriched AuPd mixtures.