Preparation Of P3MT/Pt And Study Of Electrochemical Catalysis On Formic-Formate Oxidation

3-methylthiophene was polymerized via chemical oxidation to achieve poly(3methylthiophene)(P3MT)with ferric trichloride as oxidizing agent.P3MT-modified Pt electrode(P3MT/Pt)was prepared on the matrix of platinum(Pt)by in-situ polymerization method.P3MT and P3MT/Pt were characterized by Fourier transformed infrared spectrum(FT-IR),scanning electron microscopy(SEM),energy dispersive X-ray spectroscopy(EDS),and X-ray diffraction(XRD)analyses.The electrocatalytic activities of P3MT/Pt was characterized by cyclic voltammetry(CV)and amperometric curve(j-t).The results indicate that the synthesized P3MT and P3MT/Pt present good electrochemical properties when the molar ratio of ferric chloride to 3-methylthiophene monomer is 2:1 and the polymerizing time is 2 h.Under these conditions,the prepared P3MTis fibrous with the diameter size of 70-200 nm,and its electric conductivity is 38.3 S-m-1.The electrochemical experimental results exhibit that,in the mixture of 3.0 mol·L1 HCOONa and 0.2 mol·L-1 H2SO4,the integral area ratio of forward oxidation peak to backward oxidation peak of the P3MT/Pt is 0.6 that is 1.9 times of pure Pt electrode.These results prove that P3MT is beneficial to keeping Pt away from the adsorption of CO or CO-likely species and suppress Pt poisoning.On the other hand,in 3.0 mol·L-1 HCOONa solution,the integral area ratio is 0.4 which is also smaller than that the ratio of 0.6 in the mixture sodium formate and sulfuric acid solitoin.More results show that,in this system,an appropriate working concentration range of HCOONa is 2.0-4.0 mol·L-1 and its best work concentration is about 3.5 mol·L-1.Based on of the above,the CV behaviors of P3MT/Pt electrode in the mixture of HCOONa and H2SO4,HCOOH,HCOONa and the mixture of HCOONa and NaOH are compared and the results also indicate that the electrocatalytic activity of P3MT/Pt electrode in the mixture of HCOONa and H2SO4 is the best among the four kinds solutions.This may be related to P3MT modification of Pt electrode and the adsorption of Pt to free HCOO-and free HCOOH in the solutions.The concentration of free HCOO-has an absolute advantage over the free HCOOH in the system.The main anodic oxidation pathway is the oxidation of free HCOO-along with restricted direct oxidation and indirect oxidation of HCOOH.