Mwcnts/Fe-co/PANI Composite For Counter Electrode

A high cost has been the threshold of dye-sensitised cells (DSSC) in large commercial application. Although its photovoltaic conversion efficiency can be as high as11%, but the existence of dye and Pt become its shortcomings. Most researchers engaged in using relative cheaper materials to replace precious metals Pt on DSSC counter electrode. The counter electrode in DSSC plays an important role, it is the catalytic for reducing I3-to I-and completing the whole cycle of electron transfer process. There have been many studies working to reduce costs and improve the photoelectric efficiency of DSSCPolyaniline(PANI) become the most potential alternative conductive polymer to the electrode, because its easy synthesis, high conductivity and unique REDOX property. In recent years, different forms of polyaniline electrodes were prepared, all of which have very good electrical properties.In recent years, transition metal nanoparticles and its dual metal alloy has caused a great attention in catalysis field, such as the decomposition of methanol, polymerization of ethylene and fuel cell. They can provide catalytic activity center in the catalyst. Carbon nanotubes with excellent properties were also caused a wide range of attentions, it has high mechanical strength, thermal stability and excellent electrical properties, especially high catalytic activity for the reduction of I3-. These important properties make carbon nanotubes widely used in many different fields, such as capacitor, battery, field emission display, nano additives. Because carbon nanotubes have regular, pore structure and the nature of the high surface area, they have caused more and more attentions as the carrier of nanoparticles catalyst.Carbon nanotubes and polyaniline composite material also has a wide range of applications, but the composite material as counter electrode alternatives in DSSC has not reported. In these paper, multi-walled carbon nanotubes(MWCNTs) were used as carrier, and we choose iron, cobalt as metal particles, prepared MWCNTs/Fe-Co/PANI compounds.Field Emission Scanning Electron microscopy (FESEM) and X-ray Diffraction (X-ray Diffraction, XRD), Fourier infrared Spectrometer (FTIR), Fourier Raman Spectrometer (FIIR-Raman) were used to characterize the the structure and morphology of electrode material; The cyclic voltammetry(CV) was used to analys electrochemical properties of electrodes. Through the comparison of the catalytic activity to I3-, probe the contact between polyaniline coating and the catalytic activity; Through the analysis to the internal structure of composites, explore intrinsic connection and catalytic mechanism of metal nanoparticles. The results show that:(1) The electrode composite material MWCNTs/Fe-Co/PANI is successfully prepared through chemical suspension polymerization method.(2) SEM shows that complex material formed a micro porous mesh structure, which strengthened the the electrolyte adsorption on composite material. Through the XRD can speculate that iron, cobalt in MWCNTs/Fe-Co/PANI composite formed nano alloy particles, and dispersed in carbon nanotubes matrix. The dispersed nano particles are beneficial to improve electrical catalytic performance of composite.(3) The cyclic voltammetry indicate that composite electrode has strong catalytic activity to I3-/I-REDOX reaction, the charge transfer impedance is low, catalytic reaction is faster than platinum electrode, and it is sustainability. Because of the easy preparation process, low cost, high catalytic efficiency, MWCNTs/Fe-Co/PANI become an ideal material to replace platinum in counter electrode of dye-sensitised cells.