الفهرس | Only 14 pages are availabe for public view |
Abstract The aim of this thesis was devoted to the design of a novel electrode as was described consisting of p1,2-DAAQ / GC modified electrode by electro-polymerization method using cyclic voltammetry technique (CV) followed by electro-deposition of second layer of Pd or Pt using CV technique to produce Pd/p1,2-DAAQ/GC, Pt/p1,2- DAAQ/GC, Pt/Pd/p1,2-DAAQ/GC and Pd/Pt/p1,2-DAAQ/GC modified electrodes. This developed modified electrode was applied toward the oxidation of small organic molecules (MeOH, EtOH and EG) at bare GC, modified p1,2-DAAQ / GC and modified Pd/p1,2-DAAQ/GC, Pt/p1,2- DAAQ/GC, Pt/Pd/p1,2-DAAQ/GC and Pd/Pt/p1,2-DAAQ/GC electrodes. The thesis consists of three chapters as follows: Chapter one : This chapter focused on general background of modified electrodes, how to modify electrode surface electro-chemically and the conducting polymers with special focus on poly diaminoanthraquinon and what makes polymers conductive, their synthesis by introducing highlights about both chemical and electrochemical polymerization and its applications. Also we paid a great attention to metal nanoparticles and specially (palladium ,platinum). We introduced the importance of fuel cells in our life and importance of electrochemistry in fuel cell and the techniques applied in this work . Finally we reported a general background about the organic compounds under investigation in our study. Chapter two : This chapter reported the experimental part which mainly deals with electrochemical preparation of p1,2-DAAQ / GC modified electrode in acetonitrile containing 0.1 M LiCLO4in the presence of 0.1mM of DAAQ monomer at GC electrode using CV technique The electrode potential was swept at a rate of 0.05 Vs-1 between 0.2 and 1.4 V for 15 cycles and followed by electrochemical preparation of the outer layer of monometallic Pd or Pd catalyst prepared by immersing p1,2-DAAQ modified electrode in aqueous solution of 0.1 M H2SO4 containing 2.5 mM PdCl2 or 0.1 M HClO4 containing 2.5 mM H2PtCl6 performing Pd/p1,2-DAAQ/GC and Pt/p1,2-DAAQ/GC catalyst electrodes respectively. CV technique was used for MNPs electro-deposition by cycling the potential between − 0.35 and + 0.65 V at a scan rate of 0.05 Vs-1 for 25 cycles. Measurement of ESA of the new modified electrodes was examined .Finally we reported the preparations of the solutions of the studied small fuel cell organic compounds. Chapter three : This chapter disclosed the characterization of poly 1,2 - diaminoanthraquinon (p1,2-DAAQ) based in glassy carbon electrode in in acetonitrile containing 0.1 M LiCLO4 by cyclic voltammetry technique. The optimum conditions for the film formation were investigated and the results showed that sweeping the electrode potential between 0.2 to 1.4 V using scan rate 0.05 V s-1 for 15 cycles were the optimum conditions. Also we introduced the characterization of electro-depostion of pd or Pt on the p1,2-DAAQ / GC modified electrode. The optimum conditions for the second layer were also investigated. The results showed that sweeping the electrode potential between -0.35 to +0.65 V using scan rate 0.05 V s-1 for 25 cycles are the optimum experimental conditions. Pd/p1,2-DAAQ/GC, Pt/p1,2-DAAQ/GC, Pt/Pd/p1,2-DAAQ/GC and Pd/Pt/p1,2-DAAQ/GC modified electrodes characterized by CV, energy dispersive X-ray spectroscopy (EDX) and scanning electron microscope (SEM) and the results are presented coherently and in details. The electro-oxidation of small organic compounds like Methanol (MeOH), Ethanol (EtOH) and Ethylene glycol(EG) at bare GC, p1,2- DAAQ / GC and Pd/p1,2-DAAQ/GC, Pt/p1,2-DAAQ/GC, Pt/Pd /p1,2- DAAQ/GC and Pd/Pt/p1,2-DAAQ/GC modified electrodes in alkaline medium studied using CV techniques. Different analytical parameters such as Concentration of both solvent and MeOH, EtOH and EG ,Scan rate ,Upper potential limits, continuous cyclic and chronoamperometry were reported and discussed. |