Morphological and microstructural analysis of Pb-Co electrodeposits

Full text: Pb-Co coatings have attracted the attention of researchers because its great potential in electrochemical systems where the anodic reaction is the oxygen evolution reaction (OER), due to its high corrosion resistance and catalysis of the OER. In the literature there are few studies that address the synthesis and characterization of these coatings, but no detailed studies referred to the morphology or microstructure of Pb-Co coatings are reported. Thus, the aim of this work is to characterize the morphology and microstructure of Pb-Co coating electrodeposited on a Ti substrate. Scanning Electron Microscope (SEM), High Resolution Transmission Electron Microscope (HRTEM), X-Ray Diffraction (XRD) and Energy-dispersive X-ray spectroscopy (EDS) were used for studying morphology, microstructure and chemical composition of the coatings, respectively; further Fast Fourier Transform FFT analysis was performed to the images obtained from HRTEM. Additionally, polarization curves were made to assess the capacity of catalysis of the coatings. The results showed a large surface area, demonstrating that Pb-Co films are composed of a pseudo-amorphous matrix of Pb-Co with Pb nanoparticles dispersed on it. Furthermore, the FFT analysis revealed the presence of internal stress in the nanoparticles, which could be attributed to residual stresses due to the deposition technique and/or to the presence of Co atoms into the crystal lattice of Pb. The characteristics of the coating produce numerous active sites that favor the OER given to the coating the electrocatalyst property. (author)