Dissertation > Industrial Technology > General industrial technology > Materials science and engineering > Composite materials

Studies on the Electrochemical Properties of PANI/REmOn (RE=La, Ce) Nanocomposites and the Catalysis of Pt Electrode Modified by Them to the Oxidization of CH3OH and HCOOH

Author WenYuFeng
Tutor WangJun
School Northeastern University
Course Physical and chemical
Keywords polyaniline rare earths oxide cyclic voltammetry methanol oxidization formic acid oxidization electrochemical catalyze electrochemistry degradation
Type Master's thesis
Year 2008
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Doped reagent of toluene-p-sulfonic acid (p-TSA) and oxidant of ammonium superphosphate were used to synthesize conducting polyanline (PANI)/rare earths oxide (REmOn, RE=La, Ce) composites by a chemical method. SEM image was used to characterize PANI/REmOn. Four points probes method was used to test the conductivity of these composites. The experimental results suggested that the diameters of these composites were about 100nm, and the conductivities of composites were above 10-1 S·cm-1.PANI/REmOn nanocomposites were ultrasonic distributed in metacresol solution for 20 minutes. Electrodes of PANI/REmOn nanocomposite were prepared on the indium-tin oxide glass (ITO). The cyclic voltammetry (CV) curves were measured in hydrochloric acid, sulfuric acid and phosphoric acid of different concentrations. The results showed that oxidized and reductive apex current of PANI/REmOn would increase with the increase of concentrations, while the current of electrochemistry degradation of PANI at 0.5 V in hydrochloric acid and sulfuric acid aqueous disappeared gradually. That meant the doping of La2O3 or CeO2 restrained the electrochemistry degradation of PANI in hydrochloric acid, sulfuric acid aqueous within a chosen range of concentration. Under the same conditions, electrochemical stability of PANI/CeO2 was better than that of PANI/La2O3.Electrodes of PANI/REmOn/Pt nanocomposite were also prepared on the surface of Pt electrode through the method of in-situ polymerization. The electrochemical catalyze active of the electrode PANI/REmOn/Pt to the oxidization of CH3OH and HCOOH was studied by CV method. The results showed that the electrochemical catalyze active of the electrode PANI/REmOn/Pt to the oxidization of CH3OH and HCOOH was obvious. In the mixed solution of CH3OH and H2SO4, the relation of log (|ipa|/mA·cm-2) and Epa suited a linear equation, and the linearly dependent coefficient was big enough. Therefore we could calculate the standard speed constant ks and ana (a was exchange coefficient,na was reaction electron number corresponsive the control step) in the formula of speed constant:

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