Electrodeposition of palladium nanoparticles onto indium tin oxide glass electrode. A kinetical and morphological study and effect of the potential in the particle size

Abstract

In the present work, it was conducted an electrochemical, kinetic, and morphological investigation of the electrodeposition of palladium (Pd) nanoparticles onto an Indium Tin Oxide (ITO) glass electrode. The electrodeposition was performed using a plating bath containing 0.001 M PdCl₂ and 1 M NH₄Cl at a pH of 6. The results indicate that Pd can be electrodeposited without the influence of hydrogen adsorption/desorption processes by selecting an applied potential range between 1.00 and − 0.6 V. The electrodeposition of Pd is diffusion-controlled, as evidenced by the linear relationship between the peak current (j_p) and the square root of the scan rate (ν¹^/²). The kinetic study reveals a progressive nucleation process, leading to the formation of Pd particles of varying sizes. Morphological analysis using optical microscopy and Atomic Force Microscopy (AFM) demonstrates that particle size decreases as the applied potential to the ITO substrate becomes more negative. AFM images indicate that the average heights of the Pd clusters are 149.5 nm, 91.6 nm, and 79.2 nm at -0.150 V, -0.200 V, and − 0.250 V, respectively; while the diameters of the particles ranged from 120 to 735 nm at -0.150 V, from 80 to 550 nm at -0.200 V, and from 60 to 360 nm at -0.250 V. At -0.300 V, agglomeration of Pd nanoparticles was observed due to the high nucleation rate.