An improved galvanic replacement deposition method for synthesis of compact palladium coatings on copper substrates

Although copper has a lower redox potential than palladium, it is hard to prepare compact and uniform palladium coatings on copper substrates via galvanic replacement reactions. In this work, an improved galvanic replacement method was developed to achieve facile synthesis of compact palladium coatings on copper substrates in the presence of coupled aluminum foils. The aluminum foils played an important role in donating electrons for palladium deposition instead of copper substrates. The SEM, EDS and XRD results revealed the deposited coatings showed homogeneous surface morphology and were composed of pure palladium. The obtained palladium coatings had good oxidation resistance, and could maintain the silver-white appearance after annealed at 200 °C for 10 min. The palladium coatings became denser owing to the sintering effect of thermal treatment, and therefore possessed lower corrosion current density in 3.5 wt% NaCl solution in the electrochemical experiments.