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Enhanced Urea Activity of Oxidation on Nickel‐Deposited Tin Dendrites
Author(s) -
Singh Ramesh Kumar,
Subramanian Palaniappan,
Schechter Alex
Publication year - 2017
Publication title -
chemelectrochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.182
H-Index - 59
ISSN - 2196-0216
DOI - 10.1002/celc.201600862
Subject(s) - urea , dielectric spectroscopy , electrochemistry , raman spectroscopy , nickel , catalysis , electrode , scanning electron microscope , materials science , tin , inorganic chemistry , inductively coupled plasma , chemistry , analytical chemistry (journal) , metallurgy , plasma , organic chemistry , composite material , physics , optics , quantum mechanics
Urea oxidation has gained tremendous research interest, owing to its application in direct urea fuel cells and urea electrolyzers. In this work, the electrochemical oxidation of urea on a Ni/Sn dendrites catalyst is investigated. Ni and Ni/Sn dendrites are synthesized through electrodeposition on porous Toray © carbon paper. The prepared catalysts were characterized by scanning electron microscopy, X‐ray diffraction, and inductively coupled plasma−optical emission spectroscopy. The Ni/Sn dendrites oxidized 0.33 M urea in alkaline solution at an onset potential of 0.34 V vs. Ag/AgCl with a current density of 44 mA cm −2 @0.55 V, which is higher than that of electrodeposited Ni/TC (31 mA cm −2 @0.55 V). In situ Raman spectroscopic measurements indicate that urea oxidation on Ni/Sn dendrites is initiated by Ni(III)OOH species. Electrochemical impedance spectroscopy patterns of Ni/Sn dendrites in the presence of urea displayed a single depressed semicircle at potentials of 325 mV and two semicircles above 325 mV with a decreased total charge‐transfer resistance. The Ni/Sn dendrites electrode shows lower resistance at the tested potentials, indicative of faster urea oxidation kinetics.