In this thesis, various electrocatalysts were prepared such as Pd nanoparticles and Pd-Cu and Pd-Sn alloys on reduced graphene oxide (rGO) substrate and Pd electrochemical deposition on a new substrate of reduced graphene oxide/ poly (melem-formaldehyde) nanocomposite (rGO/PMF) NC for ethanol oxidation reaction (EOR). Than, different elechtrochemical tests were performed in low ethanol concentrations in order to application in fuel cell-based breath alcohol analyzer (FCBrAA) in alkaline media. In the following, samples characterization were applied using several techniques such as fourier transform infrared (FT-IR), raman, X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and Barrett-Joyner-Halenda (BET), Brunauer-Emmett-Teller (BJH) analysis. In the first section, Pd nanoparticles and alloys of Pd-Cu with different palladium atomic ratios were synthesized on the rGO support. The highest activity and the lowest onset potential (Eonset) in the EOR were obtained for the Pd0.9-Cu0.1 /rGO sample. The electrochemical performance of Pd/rGO and Pd0.9-Cu0.1/rGO were compared at different concentrations (5, 10, 20, 30, 40, 50). The cyclic voltammetry eva‎luations results showed a long-term durability for Pd0.9-Cu0.1/rGO in comparison to the Pd/rGO during 600 cycles. In the second section, alloys of Pd-Sn with different palladium atomic ratios were synthesized on the graphene oxide support as the EOR electrocatalysts in low ethanol concentrations in order to use in FCBAAs. The highest activity and the lowest onset potential in the ethanol electrooxidation reaction were obtained for the Pd0.8-Sn0.2 /rGO sample. In the third section, eva‎luation of ethanol fuel cell has been performed at different concentrations for the Pd0.9-Cu0.1/rGO synthesized catalyst on the nickel foam as an anode electrode and the Fe-Co/KB nanocatalyst on a carbon cloth substrate as a cathode electrode in an alkaline media at a temperature of 34 ₒC. Comparison of the electrochemical performance of this catalyst has been investigated using power, I-V and anodic and cathodic polarization curves. The current discharge of I-V curve stoped in 3.285, 2.683, 2.266, 2.135, 1.005 mA cm-2 for concentrations 50, 40, 30, 20, 10, 5 mM, respectively. In the last section, (rGO/PMF) NC were fabricated as a new substrate. Several techniques were applied for the structural and chemical characterization of (rGO/PMF) NC. The specific surface area and average pore diameter of (rGO/PMF) NC were 481.61 m2 g−1 and 10.23 nm, respectively. The plentiful nitrogen of (rGO/PMF) NC can increase the anchoring Pd NPs; as a result, the more electrodeposition of Pd NPs on substrate enhanced the more electrochemical activity. Eonset of Pd/(rGO/PMF) NC was negatively shifted to 110 mV, as compared to Pd/rGO and the current density of Pd/(rGO/PMF) NC was enhanced in comparison to Pd/rGO. Nitrogen doping and structural defects are given escalade strong electron transfer among Pd NPs and (rGO/PMF) NC support, improve the Pd NPs dispersion, and catalyst activity. Pd/(rGO/PMF) NC was applied as the ethanol oxidation reaction electrocatalysts in low ethanol concentrations in order to use in FCBAAs in alkaline media. This work not only suggested a favorable catalyst for EOR, but also improved a nitrogen-based material, which could be regarded as supporting materials for different catalysts and other related fields. The results of the research can be used for the development of an anion-exchange membrane fuel cell anode for breath alcohol analyzer application.

محمد ژياني

بهزاد رضايي، امير عبدالملكي

علي اصغر انصافي، اسماعيل شمس سولاري، محمد محسن مومني