پديدآورندگان :
Shahbazi Farahani Fatemeh Dept. of Analytical Chemistry, Faculty of Chemistry, University of Tabriz, 51664 Tabriz , Majidi Mir Reza majidi@tabrizu.ac.ir Dept. of Analytical Chemistry, Faculty of Chemistry, University of Tabriz, 51664 Tabriz;
كليدواژه :
Manganese dioxide , nitrogen , doped carbon , oxygen reduction reaction , neutral media
چكيده فارسي :
Poor kinetics of the oxygen reduction reaction electrocatalysts (ORR) at neutral pH and low temperatures can hinder the performance and development of fuel cells under these conditions [1]. A viable approach for reducing costs, while enhancing ORR, is the use of platinum group metal (PGM) free catalysts. Previous literature reports have shown that PGM-free catalysts obtained by supporting transition metal, such as Fe and Co, on different carbon supports can be used as cathode achieving an electrochemical performance comparable to that of Pt [2]. In fact, there are two possible ways of oxygen reductions that can take place: oxygen can be reduced to water by direct 4-electron pathway or to peroxide by 2-electron pathway. For achieving high power performance in MFCs and avoid peroxide formation, the direct 4-electron pathway is a mandatory requirement of ORR catalysts [3]. Also, thanks to low cost, natural abundance, environmental friendly nature, and good electrochemical properties, electrode materials based on manganese dioxide (MnO2) have been tested for ORR catalysts [4]. In this work, a novel multivalent MnOx supported on nitrogen doped carbon and reduced graphene oxide (C(N)/ MnOx-SP, rGO(N)/ MnOx-SP) was synthesized via a solid state method. The cathodic oxygen reduction reaction (ORR) in neutral media was improved by modified electrode with manganese based catalysts. The synthesized catalysts were characterized by X-ray diffraction (XRD), Raman spectroscopy, field emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy to reveal their crystalline structure, morphology and chemical composition. Electrocatlytic behavior of prepared materials for ORR performance was measured by cyclic voltammetry, linear sweep voltammetry and electrochemical impedance spectroscopy. C(N)/ MnOx-SP showed good performance toward oxygen reduction with 4-electron pathway dominantly. As such it can be selected as an air breathing cathode to be applied in microbial fuel cells which operate in neutral media. These results indicate that the representative sample is a good candidate to be used in practical MFC applications owing competitive price and good performance ORR process.
