Effect of processing parameters on size, density and oxygen reduction reaction (ORR) activity of Pd nanoparticles grown by spin coating

To study oxygen reduction reaction (ORR) activity Pd nanoparticles were grown on flat (Si and glass) substrate via spin coating of Pd2 + ions solution followed by chemical reduction in aqueous hydrazine hydrate solution. Growth of Pd nanoparticles was confirmed by x-ray diffraction and x-ray photoelectron spectroscopy techniques. UV-vis-NIR spectroscopy was used to optimize reduction time, whereas scanning electron microscopy was utilized to study size and distribution of grown Pd nanoparticles. It was observed that most of the Pd nanoparticles grow with unique preferable size. The preferable size and density of grown Pd nanoparticles can be precisely controlled by processing parameters (rpm, ramp and reducing agent concentration). The grown Pd nanoparticles are thermally stable up to 450 °C. The ORR activity was found to be dependent on size as well as density of Pd nanoparticles.