Pem yakıt hücresi katotunda kullanılmak üzere platinin ikili alaşımlarının farklı yöntemlerle sentezi, karakterizasyonu ve elektrokatalitik özelliklerinin incelenmesi


Thesis Type: Post Graduate

Institution Of The Thesis: Gazi Üniversitesi, Fen Bilimleri Enstitüsü, Turkey

Approval Date: 2010

Student: NİDA ARAS

Consultant: FATMA ÇİĞDEM GÜLDÜR

Abstract:

Fuel cells are devices that directly convert the chemical energy to electrical energy . Within many types of fuel cells, PEM (polymer electrolyte membrane) fuel cell is the most prefferred one. Indeed, PEM fuel cell is the most promising candidate as an energy source thanks to its advantages. One of the major problems in front of the commercialization of PEM fuel cell is that they need the use of very expensive platinum based electrocatalysts. Furthermore, the voltage produced by PEM fuel cell is limited by the low kinetic rate of the oxygen reduction reaction (ORR) occuring at the cathode. In this study, it was aimed to develop cheap and active catalysts that can be used in the electrocatalysis of the ORR reaction at the cathode of the PEM fuel cell. The catalysts were prepared by depositing the catalysts of platinum with the transition metals; Ag, Cu and Fe on carbon support by wet impregnation reduction (sodium bor hydrate with standart mixer) and (sodium bor hydrate with ultrasonic mixer) . In first stage, Pt-Fe/C 6:1 catalyst was prepared. Particul sizes were found 2,52 nm with ultrasonic mixer and 1,78 nm with standart mixer. CV results were found 2.5 times better than standart mixer. But, cyristal shape of ultrasonic mixer using catalyst found amorphe. In second stage, totally 18 catalyst prepared with two methods. Particule sizes were calculated between 1,78 and 6,78 nm. XRD and CV analyzed particule size; 2,58 nm ve amount of load; 2,894 mC, electroactive surface area; 476,85 cm2/mg, mass activity; 256,60 mA/mgPt, spesific activity; 0,538 mA/cm2 best result found in PtCu/C-11 with ultrasonic mixer catalyst.