Electrocatalytic activity of nickel nanoparticles deposited on high surface area tin dendritic supports toward urea oxidation

Srikanth Kolagatla, Department of Biological Chemistry, Ariel University, Ariel, Israel
Palaniappan Subramanian, Department of Biological Chemistry, Ariel University, Ariel, Israel
Alex Schechter, Department of Biological Chemistry, Ariel University, Ariel, Israel

Urea is a cheap and widely available commodity, which is non-toxic, stable, and therefore easy to transport and store. This is a promising material which can be used as a hydrogen carrier either directly or as a source of ammonia. Electrolysis of urea that directly converts urea to hydrogen through electrochemical oxidation with an inexpensive nickel catalyst is been studied extensively because, the nickel catalysts showed both higher current densities and lower oxidation potentials for the electro-oxidation of urea than those of the noble metal catalysts. However, there exist a large over potential between the theoretical oxidation potential (-0.4 V Vs SHE) and observed oxidation potential (0.45 V Vs. SHE) using nickel catalyst in electro-oxidation of urea. Nanostructured metal particle has been widely used as catalyst support to exploit the high surface area of these materials. In this context, herein we report the electrosynthesis of tin dendritic structures generated from electroreduction of SnCl₂ in presence of sodium citrate as support for nickel nanoparticles. Nickel nanoparticles electrodeposited on Sn dendritic structures were characterized using SEM, XRD and ICP measurements. Cyclic voltammetry was used to evaluate the catalytic activity of Ni nanoparticles on tin dendritic supports. In addition, in-situ surface enhanced Raman spectroscopic experiment was performed to understand the potential dependence of nickel hydroxide catalyst obtained in the presence of urea.