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Methanol electro‐oxidation is investigated at graphite electrodes modified with various platinum and nickel nano‐particle deposits using cyclic voltammetry. The modified electrodes are prepared by the simultaneous electrodeposition of metals from their salt solutions using potentiostatic and galvanostatic techniques. They show enhanced catalytic activity towards methanol oxidation in KOH solution. The catalytic activity of platinum nano‐particles is found to be significantly affected by the presence of relatively small amounts of nickel deposits. A comparison is made between the electrocatalytic activity of Pt/C and (Pt‐Ni)/C electrodes. The results show that the methanol electro‐oxidation current increases with an increase in the nickel content. In particular, the highest catalytic activity is achieved for platinum to nickel deposits of 95%:5% (wt.‐%), in other cases the catalytic activity decreases. It is found that Ni enhances the catalytic activity of Pt by increasing the number of active sites, as well as through an electron donation process from Ni to Pt. This process takes place once the nickel hydroxide (Ni(OH)2)/nickel oxy‐hydroxide (NiOOH) transformation begins. The effect of the methanol concentration on the methanol oxidation reaction is investigated. The order of reaction, with respect to methanol, at the modified (Pt‐Ni)/C electrode is found to be 0.5.

Development of efficient catalysts for urea electrooxidation is a current issue due to its ability to generate H2and its use as fuel for low-temperature fuel cells. In this work, non-precious Ni and Ni-metal oxide (PbO2and 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−2at +570 mV), (27 mA cm−2at +460 mV), and (18.5 mA cm−2at +440 mV), respectively. The 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 cm2for PbO2-Ni/C, Bi2O3-Ni/C 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 H2production, direct urea fuel cells, and water treatments is possible.