Different Carbon Materials And Poly-o-anisidine Synergistic Supported Pt Nanoparticles As A Highly Efficient Catalyst For Electrocatalytic Oxidation Of Small Organic Fuels

As a new type of clean energy,fuel cell has both high energy conversion efficiency and high energy density which combines the advantages of generators and batteries.It is a promising power conversion device for future energy supply.Amongst the fuel cells,small organic fuels such as methanol,formaldehyde and ethanol are renewable and easy to store and transport,which are widely used in fuel cels.Platinum is the most ideal catalyst in these liquid fuel cells,but its high cost and easy poisoning by intermediate products which directly limit the commercial development of liquid fuel cells.Therefore,it is particularly critical to find an effective way to reduce the loading of noble metal catalysts.In this regard,choosing a support material with a larger specific surface area can improve the dispersion of the catalyst and increase its electrocatalytic efficiency;furthermore,adding non-noble metals or metal oxides to the noble metals can also achieve the purpose of reducing costs and improving electrocatalytic activity.Conductive polymer is an environmentally friendly electrode material with low cost,large specific surface area and superior conductivity.Combining it with carbon material and applying it as a support of catalyst can improve the electrocatalytic performance of the composite electrode.In this study,activated carbon(YBC)and carbon-coated silicon(Si@C)were mixed into the graphite powder to prepare the different doped carbon paste electrodes.The Pt nanoparticles were electrodeposited onto the doped carbon paste electrode surface by using potentiostatic method to fabricate of the Pt/YBCPE and Pt/Si@C,which were used for the electrocatalytic oxidation of formaldehyde and methanol.In order to further improve the electrocatalytic activity of the working electrodes,the CPE(pure carbon paste electrode),YBCPE and CPE-Si@C were modified with poly-o-anisidine(POA).After electrodeposition of Pt,the electrocatalytic oxidation performance of the different working electrodes on fuel molecules was compared and investigated.The contents of this research are as follows:(1)Study on electrocatalytic oxidation of formaldehyde on activated carbon doped carbon paste electrode modified with poly-o-anisidineDifferent mass percentage of activated carbon(YBC)doped carbon paste electrodes(YBCPE)were firstly prepared,then electrodeposition of Pt nanoparticles was performed to prepare working electrodes Pt/YBCPE.It was shown that Pt/YBCPE(16%)exhibits the highest mass activity for formaldehyde oxidation compared to platinum deposited on carbon paste electrode(CPE)and other YBCPE(X%)electrodes.Afterwards,poly-o-anisidine(POA)film was prepared by electro-polymerization onto the CPE and YBCPE(16%)in o-anisidine monomer solution and then Pt nanoparticles were electro-deposited at the POA film surface for fabrication of the Pt/POA/CPE and Pt/POA/YBCPE composite electrodes.The morphology of the composite electrodes was characterized by SEM,XRD and XPS which revealed that the presence of YBC and POA in the composite electrodes significantly improves the dispersion of Pt nanoparticles on the electrodes.Electrochemical impedance spectroscopy(EIS),chronoamperometry(CA)and cyclic voltammetry were used to verify the Pt/POA(16m C)/YBCPE(16%)exhibits the excellent conductivity,durability and electro-catalytic activity towards the formaldehyde oxidation.This may be attributed to the synergistic effect between the catalyst and support,thereby providing more and stronger active sites for the electrooxidation of formaldehyde.(2)Study on electrocatalytic oxidation of methanol on Si@C doped carbon paste electrode modified with poly-o-anisidineThe 10% mass percentage of Si@C was mixed into graphite powder to prepare CPE-Si@C,and then modified with POA to obtain POA(X)/CPE and POA(X)/Si@C(10%).Electrocatalytic oxidation of methanol was carried out after Pt nanoparticles were electrodeposited on these composite electrodes.Cyclic voltammetry test results show that Pt/POA(12m C)/Si@C(10%)has the best electrocatalytic activity.SEM results show that the distribution of Pt on this electrode is the most uniform.The results of EIS and CA prove that the Pt/POA(12m C)/Si@C(10%)has higher stability and conductivity than other electrodes.These research results prove that the presence of Si@C and POA increase the electrochemically active surface area of the composite electrode,and the synergistic effect between them and Pt enhances the efficiency of the methanol oxidation reaction.(3)Study on electrocatalytic oxidation of ethanol on carbon paste electrode modified with poly-o-anisidinePt/POA(X)/CPE composite electrodes were prepared by electropolymerization of POA on pure carbon paste electrode(CPE),Pt particles were electrodeposited on the POA film which used for electrooxidation of ethanol.The effects of the electropolymerization potential,thickness and concentrations of POA on the electrocatalytic activity of the ethanol were investigated.The experimental results showed that the electrocatalytic efficiency of Pt/POA(16m C)/CPE was the highest.The charge tranefer resistance between the POA/CPE and electrolyte was studied by EIS,the results show that the presence of POA improves the dispersion of the catalyst and enhances the electron transfer of the substrate electrode.