Synthesis and Electrochemical Properties of Pure Pt, Au, and Pt-Au Alloy Catalysts on Titanium Oxide Nanotubes (TONs)

Using pulse electrodeposition (PED), three kinds of nanoparticles (NPs), namely Pt/TONs, Au/TONs, and Pt-Au/TONs, were deposited at three different charge densities using highly ordered titanium oxide nanotubes (TONs) substrate. Structures, compositions, and electrocatalytic activity towards oxygen reduction reaction (ORR) and stability were investigated by SEM, X-ray diffraction, EDX, ICP composition analysis, and cyclic voltammetry. The characterization demonstrated that the structural features and compositions of the as-prepared NPs varied with deposition conditions. The electrochemical activity of these NPs was examined in 0.5 M H₂SO₄ solution in the absence and presence of oxygen using cyclic voltammetry (CV) technique for each electrode. Results indicate that, due to its high dispersion, the Pt/TONs catalyst deposited at higher charge density shows enhanced ORR activity among all the electrocatalysts. The stability tests indicate that the Pt/TONs are more stable than the Pt-Au/TONs having same deposition charge density (17.6 C cm^-2) in N₂-saturated H₂SO₄ solution.