The Preparation Of PANI-POMAN Supported Cu@M Catalysts And Their Electrocatalytic Activity

As a d irect electroche mica lly convert che mica l energy into electrica l energygenerating device, fue l cells occupy an important positio n in terms of energyapplication in the21st century. Direct formic ac id fuel ce ll has broad applicationprospects in the fie lds o f military, aerospace and mobile devices, for the ir wide rangeof fue l sources, high-energy convers ion effic ienc y, low environmenta l pollution,convenie nt for storage and transportation. Currently, the low e lectroche mica l activityof electrode catalyst and the high-cost of precious meta ls rema ins a large obstacle tothe ir commercia lization. Improving the catalytic activity and reducing the amount ofprecious meta ls is o f great importance for lower cost of the fue l cell. In this work, t heelectrode surface polyaniline-poly (o-methoxya niline) noble meta l nanopartic lecompos ite catalyst in the platinum film was prepared with e lectroche mica l methods,such as constant potentia l deposition methods and cyc lic volta mmetry. Scanningelectron microscopy (SEM), high resolution trans miss io n electron microscopy (TEM),EDS spectrometer and X-ray powder diffractio n (XRD) and other research methodswere utilized to characterize the structure and compos ition, and electrochemica lmethods was utilized to study the catalyst for formic acid electro-catalytic oxidation,the main research works are as follows:(1) Polyaniline-Poly (o-methoxya niline)(PANI-POMAN) compos ites were synth-esized with cyclic volta mmetry (CV) methods. Platinum (Pt) and Ruthe nium (Ru)bimetal na nopartic les were co-deposited onto the PANI-POMAN film to produce adurable and effic ie nt electro-catalyst for formic acid oxidation. The morpho logy ofcompos ite/catalysts was characterized by scanning electron microscopy (SEM) andtransmiss io n electron microscopy (TEM). The electrocatalytic activity o f the catalyststoward formic acid oxidation was investigated wiht CV and other electrochemica lmethods. The metal nanoclusters having average partic le size of5nm as measureddirectly from TEM ima ges.The PANI-POMAN supported bimeta llic cata lyst exhib itedtwo times higher cata lytic activity than that for pure PANI supported cata lyst, and hada much better stability. The high activity was due to the uniq ue porous, la yeredstructure, high s urface area, and uniform d istributio n of Pt-Ru na nopartic les. Theenhanced stability was attributed to the introduction of Ru meta l into Pt catalyst todispla y a synergistic effect, and the ability of reduc ing the propensity o f poisoning o fthe catalyst by the intermediate products. (2) Pure Pt, Cu@Pt, PANI-POMAN (1:1)/Pt and PANI-POMAN (1:1)/Cu@Ptcompos ite catalyst were prepared by the constant potentia l method. The morpho logyof the catalyst was characterized by SEM, TEM, and compositio n analys is wascharacterized by EDS; the electroche mical properties of the catalyst werecharacterized by cyc lic vo lta mmetry, chronoa mperometry. The characterizatio n ofmorpho logy showed that PANI-POMAN/Cu@Pt composite cata lyst meta l particleswere uniformly d ispersed in the polymer structure of three-dime ns iona l space,forming catalysts with Cu as the nuc lear and Pt core-shell as the she ll.Electrocatalytic oxidation o f formic acid ind icates that the utilizatio n ofPANI-POMAN and Cu, Pt bimetal improved electro-cata lytic oxidation of formic acidactivity and poiso ning resista nce of platinum to formic acid, meanwhile reduced thecost with the introductio n of Cu, improved utilization of precious metals.Electro-catalytic oxidation of formic acid sequence by different electrodes is asfollows: PANI-POMAN/Cu@Pt> PANI-POMAN/Pt> Cu@Pt> Pt.(3) The preparation of PANI-POMAN/Cu@Pd catalyst was done with theelectrochemica l method. The characterizatio n by SEM showed that polyaniline-poly(o-methoxyaniline) three-dime ns iona l structure of the co mposite film accelerated thedispersion o f metal nanoparticles.PANI-POMAN is not only a good electronicconductor, but also a good proton conductive materia l, improving electro-catalyticproperties of the cata lyst. The direct dehydrogenatio n and oxidatio n pathway was thema in oxidation mechanis m of formic acid on the PANI-POMAN/Cu@Pd electrode,different fro m the indirect oxidation mechanis m of formic acid on the Cu@Pd,ANI-OMAN/Cu@Pd electrodes. There is a synergistic effect between Metallic Pd andPANI-POMAN compos ite me mbrane, accelerating Pd electrocatalytic oxidation offormic acid, improving the performa nce of the catalyst in the anti-drug o f theelectrochemical reaction process effectively.