Poster presented at: 4th International Congress of Chemists and Chemical Engineers of Bosnia and Herzegovina, June, 30th-July, 02nd, Sarajevo, Bosnia and HerzegovinaAbstract: [https://cer.ihtm.bg.ac.rs/handle/123456789/5215

Nikolić, Nebojša D.

Stevanović, Sanja

Tripković, Dušan

Central Repository of the Institute of Chemistry, Technology and Metallurgy (CER)

Influence of treatment of various carbon supports on electrochemical activity of Pt catalystsSanja I Stevanović, Dušan V Tripković, Nebojša D Nikolić Institute of Chemistry, Technology and Metallurgy, University of Belgrade, Njegoševa 12, 11 000 Belgrade, SerbiaThis work was financially supported by the Science Fund of the Republic of Serbia under the grant No 7739802. World energy crisisWhy We Need Alternative Energy Resources?Depletion of fossil fuels and the realitiesof global warming have inspiredmankind to search for renewable powersources than can meet demand forenergy in a more sustainable manner.Role of the catalysts supportWhy  methanol as a fuel?Direct methanol fuel cells (DMFCs) are verypromising power sources for stationary andportable electric devices due to its highefficiency and low emissions of pollutants,low operating temperature, high energydensity, nontoxic and environmentallyfriendly characteristicsCatalysts support is essential for nanostructurednoble metal catalysts activity and stability sincethat interaction between the metal particle andthe support can affected on metal particle sizeand dispersion. The function of the support isalso to extend the surface area of the metal thatis, to enable efficient utilization of metals byproviding the maximum ratio of surface area andweight.EXPERIMENTAL :➢The electrochemical treatment ofpreviously polished glassy carbon (GC)electrodes was performed by anodicpolarization in 0.5 M H2SO4 at 2 Vduring 95 s.➢In situ AFM electrochemical tehniquewas employed for direct monitoring ofmorphological changes of the GCsurfaces during the electrochemicaltreatment, and to study morphologicalevaluation of platinum catalystdeposited on GC support.➢ Platinum black was attached in aform of thin layer onto the polishedand electrochemically treated glassycarbon support.➢ The catalyst electrocatalytic activitywas studied for methanol oxidationreaction in H2SO4 solution.Glassy carbon is porous material that consists of aromatic ribbon molecules randomly oriented. Oxidation of GC leads to formation and growth of oxide layer, causing higher roughness and more defects at the surface. Fig 1. Cyclic voltammograms and  image surface  of a) polished and b) oxidazed glassy carbon electrode Fig 3.The contribution of GC functional groups to methanol oxidation for GC/Ptblack and GCox/Ptblack electrodesAFM analysis of platinum catalysts showing more uniform distribution of larger number ofsmaller agglomerates at oxidized support in comparison with the polished one. Oxidation of glassycarbon leads to the changes of functional groups. From this reason, metal-support interaction isdifferent and can affect the intrinsic activity of Pt deposits. It can be concluded that the increasedactivity of GCox/Ptblack is due to higher participation of oxygen containing functional groups of theGCox support. This groups promote oxidation of COads which is the main poison in methanoloxidation reaction.-0.2 0.0 0.2 0.4 0.6 0.8 1.0-0.20.00.20.40.60.81.0  E (V vs SCE)j (mA/cm2R) GC/Ptblack GCOX/PtblackC-0.4 -0.2 0.0 0.2 0.4 0.6 0.8 1.0-0.20.00.20.40.60.81.01.2j (mA/cm2)E (V vs SCE) Pt/Cmicrowave assisted polyol synthesis➢ In order to obtain better activity of  platinum catalysts deposited on Vulcan XC support, microwave assisted polyol synthesis method was applied. ➢ In this procedure, 0.5ml of 0.05M H2PtCl6 were mixed with ethylene glycol under magnetic stirring.Then, 0.8M NaOH was added dropwise to adjust pH~12. The prepared solution were placed in thecentre of microwave oven and heated 60s at 700w. After microwave heating, the colloidal solutionswere mixed with 20 ml of water suspension of Vulcan XC-72 carbon and 150 ml 2M H2SO4 for 3 hwith magnetic stirring. The suspensions were filtered and solid residues were washed with ultra-purewater dried in N2 atmosphere at 1600C for 3h. The metal loading was adjusted to ~20 mass %.Fig 2. Cyclic voltammograms and  image surface  of a) GC/Ptblack b) GCox/Ptblack electrodesFig 4. Methanol oxidation for  Pt/C electrode

Influence of treatment of various carbon supports on electrochemical activity of Pt catalysts

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Influence of treatment of various carbon supports on electrochemical activity of Pt catalysts

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