Formic acid oxidation on AuPd core-shell electrocatalysts: Effect of surface electronic structure

AuPd core-shell electrocatalysts were synthesized with cubic, cuboctahedric and octahedral shapes to study the electronic effects of these nanostructures on the formic acid oxidation reaction, FAOR. The morphology and the surface electronic structure of the different AuPd core-shell were examined by high-resolution transmission electron microscopy, HRTEM, and X-ray photoelectron spectroscopy, XPS, respectively. The FAOR was analyzed by the binding energy of the d-band center of each core-shell nanostructure and its electrocatalytic behavior. The octahedron shape presents better affinity for the CO adsorption-desorption processes and higher overpotentials than the other electrocatalyst. Therefore, the FAOR indirect route is encouraged. Contrariwise, the cubic nanostructure favors the FAOR direct route due to its exchange current density of 1.741 mA cm−2 that suggest a fast kinetic associated with the lowest d-band binding energy among all the core-shell nanostructures.