Ispitivanje stabilnosti PtZn/C katalizatora za reakciju elektrooksidacije metanola, etanola i mravlje kiseline

Abstract

PtZn katalizator deponovan na ugljenik razvijene površine Vulcan XC-72R sintetizovan je poliol metodom uz pomoć mikrotalasne pećnice i testiran za reakciju elektrooksidacije metanola, etanola i mravlje kiseline u sumpornoj kiselini. Poređenje stabilnosti PtZn/C katalizatora za reakciju elektrooksidacije metanola, etanola i mravlje kiseline dobijeno je produženim cikliziranjem. Fizičkohemijska svojstva dobijenih katalizatora su okarakterisana transmisijskom elektronskom mikroskopijom (TEM), termogravimetrijskom (TGA) analizom i energetsko disperzivnom spektroskopijom (EDS). Prema TEM analizi, PtZn/C katalizator ima male čestice prilično slične veličine između 1 i 2 nm. TGA analiza je pokazala 27,68 tež. % metala za PtZn/C katalizator. Hemijski sastav PtZn/C katalizatora je pokazao da je odnos Pt:Zn u katalizatoru 87 tež.% : 13 tež.%. Dodavanje Zn u Pt značajno poboljšava aktivnost za oksidaciju metanola i etanola u poređenju sa Pt/C referentnim katalizatorom. Testovi stabilnosti su potvrdili da su PtZn/C katalizatori najstabilniji za reakciju elektrooksidacije metanola. Uočena visoka katalitička aktivnost i dobra stabilnost u reakciji oksidacije metanola sintetizovanog katalizatora mogu se pripisati veoma efikasnoj mikrotalasnoj sintezi i dobro izbalansiranom sadržaju Zn kao legirajućeg metala.

PtZn catalyst material deposited on high surface area carbon Vulcan XC-72R was synthesized by microwave-assisted polyol method and tested for methanol, ethanol and formic acid electrooxidation reaction in sulphuric acid. The comparison of the stability behaviour of the PtZn/C catalyst for the methanol, ethanol and formic acid electrooxidation reaction were obtained from prolonged cycling. Physicochemical properties of obtained catalysts were characterized by transmission electron microscopy (TEM), thermogravimetric (TGA) analysis and energy dispersive spectroscopy (EDS). According to TEM analysis PtZn/C catalyst have small particles of rather similar size between 1 and 2 nm. TGA analysis revealed 27.68 wt. % of metals in PtZn/C catalyst powder. The chemical composition of the PtZn/C catalyst was showed that the Pt:Zn ratio for the PtZn/C catalyst is 87 wt.% : 13wt.%. Addition of Zn to Pt significantly improves methanol and ethanol oxidation activity in comparison to Pt/C benchmark catalyst. Long term stability tests confirmed that PtZn/C catalysts are notably less poisoned for the methanol electroxidation reaction. The observed high catalytic activity and good stability in the methanol oxidation reaction of synthesized catalyst can be ascribed to the very efficient microwave synthesis and well-balanced content of Zn as alloying metal.