A method for manufacturing a palladium coated doped metal oxide conducting electrode including immersing a metal oxide conducting electrode into an aqueous solution having a palladium precursor salt to form the metal oxide conducting electrode having at least one surface coated with palladium precursor. To form a layer of palladium nanoparticles on the metal oxide conducting electrode the palladium precursor on the metal oxide conducting is reduced with a borohydride compound. The palladium nanoparticles on the metal oxide conducting electrode have an average diameter of 8 nm to 22 nm and are present on the surface of the metal oxide conducting electrode at a density from 1.5×10⁻³ Pd·nm⁻² to 3.5×10⁻³ Pd·nm⁻².