Studies On The Electrochemical Properties Of Pani/re₂o₃ (re=sm, Y) Nanocomposites And The Catalysis Of Pt Electrode Modified By Them To The Oxidization Of Ch₃oh And Hcooh

In this paper poly-aniline (PANI) was synthesized through chemical method, p-methy benzene sulfonic acid (p-TSA) was adulterant, and ammonium persulfate was oxidant. On the base of that research, rare earth oxide (Sm2O3 or Y2O3) was dispersed in p-TSA forming PANI/Sm2O3 and PANI/Y2O3 composite nano-material.Four probes method was used in detecting the conductivity of the material; the form of PANI, PANI/Sm2O3 and PANI/Y2O3 could be observed by SEM experiment.A solution method was used to prepare PANI, PANI/Sm2O3 and PANI/Y2O3 membrane on ITO conductive glases which worked as membrane electrodes. The electrochemical performance of the three kinds of membrane electrodes were studied through cyclic voltammetry (CV) method. A three electrodes system was used in the CV experiment, one of the membrane electrodes was working electrode, saturation calomel electrode was reference electrode, and platinum electrode was auxiliary elelctrode. Three kinds of modified Pt electrodes were also prepared using in situ polymerizing method on platinum plats that were expressed PANI/Pt, PANI/Sm2O3/Pt and PANI/Y2O3/Pt. The electrochemical catalysis performance of these three electrodes to HCOOH and CH3OH oxidation reaction was studied through CV method.CV result showed that:(1) The electrochemical activity was stronger when the temperature of forming membrance was 70℃. The electrochemical reaction activity strengthened with increasing of the amount of PANI/Sm2O3 and PANI/Y2O3 used for the forming membrane. (2) PANI/Sm2O3/ITO and PANI/Y2O3/ITO had no electrochemical catalysis to HCOOH and the redox character of PANI was only showed. (3) PANI/Pt, PANI/Sm2O3/Pt and PANI/Y2O3/Pt all had nice electrochemical catalysis to CH3OH. The electrochemical catalyze active of the electrode PANI/RE2O3/Pt to the oxidization of CH3OH was obvious. With the increase of the concentration, the oxidized apex current would increase through a linear equation within a chosen range of concentration. In CH3OH oxidation apex current ip,a had direct ratio with CH3OH solution concentration c*, had direct ratio with scanning rate to the 1/2 (v1/2), therefore we could calculate the standard speed constant ks and ana (a was exchange coefficient and na was reaction electron number corresponsive the control step) in the formula of speed constant: (4) PANI/Pt, PANI/Sm2O3/Pt and PANI/Y2O3/Pt all had electrochemical catalysis to HCOOH oxidation. The catalysis strengthened with the increasing of HCOOH concentration.