Page 86 - Book of Abstracts

th
8 Biannual Conference on Chemistry - CHEM 08

Urea Electrooxidation on PbO2-Ni/C and Bi2O3-Ni/C

Nanocomposites in Alkaline Medium

Hanaa. B. Hassan and Reham H. Tammam
Chemistry Department, Faculty of Science, Cairo University, Cairo 12613,
Egypt.

ABSTRACT

Development of efficient catalysts for urea electrooxidation is a current issue due
to its ability to generate H2 and its use as fuel for low-temperature fuel cells. In
this work, non-precious Ni and Ni-metal oxide (PbO2 and Bi2O3) nanocomposites
were prepared by electrodeposition technique and used as anodes for urea
electrooxidation in NaOH solution. The surface characterizations were carried
out by scanning electron microscope (SEM), energy dispersive X-ray
spectroscopy (EDX),X-ray diffraction (XRD) and X-ray photoelectron
spectroscopy (XPS) techniques. The electrocatalytic activity was investigated by
applying different electrochemical techniques. Remarkable catalytic activities
and stabilities toward urea electrooxidation were recorded for PbO2-Ni/C and
Bi2O3-Ni/C nanocomposites more than that of Ni/C. The recorded oxidation peak
current densities on PbO2-Ni/C, Bi2O3-Ni/C and Ni/C are (80 mA cm at +570
−2
mV), (27 mA cm at +460 mV), and (18.5 mA cm at +440 mV), respectively. The
−2
−2
onset potentials of the oxidation processes shifted to lower potentials by values
of +40 mV and +150 mV on Bi2O3-Ni/C and PbO2-Ni/C, respectively compared to
that on Ni/C. Electrochemical impedance spectroscopy (EIS) showed charge
transfer resistance values of 6.8, 28.9 and 42.2 Ω cm for PbO2-Ni/C, Bi2O3-Ni/C
2
and Ni/C, respectively in urea solution at +356 mV. Higher catalytic activity,
exchange current density, diffusion coefficient, electron transfer rate and lower
charge transfer resistance toward urea electrooxidation were recorded for Bi2O3-
Ni/C and PbO2-Ni/C nanocomposites. The electrocatalytic performance was
found in the order of PbO2-Ni/C > Bi2O3-Ni/C > Ni/C. Application of these
nanocomposites in applications related to H2 production, direct urea fuel cells,
and water treatments is possible.

BOOK OF ABSTRACTS CHEM 08 (2020) Page 85