Insights on the superior performance of nanostructured nitrogen-doped reduced graphene oxide in comparison with commercial Pt/C as cathode electrocatalyst layer of passive direct methanol fuel cell. (20th May 2019)

• Record Type: Journal Article
• Authors: Farzaneh, Ali; Goharshadi, Elaheh K.; Gharibi, Hussein; Saghatoleslami, Naser; Ahmadzadeh, Hossein
• Is Part Of: Electrochimica acta. Volume 306(2019)
• Page Start: 220
• Page End: 228
• Publication Date: 2019-05-20
• Subjects: Nitrogen doped graphene -- Metal-free catalyst -- Passive DMFC -- Methanol crossover -- Electrochemical impedance spectroscopy; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2019.03.120
• Languages: English
• ISSNs: 0013-4686

Abstract

Abstract: Methanol crossover is one of the major problems which reduces the performance of direct methanol fuel cells (DMFCs). Utilization of methanol tolerant cathode electrocatalysts with comparable activity, lower cost, and higher durability than those of current Pt-based electrocatalysts is an essential step towards commercialization of DMFCs. In this research, for the first time the performance of hydrothermally produced nitrogen-doped reduced graphene oxide (NRGO) with nitrogen content of 4.6 wt% was compared with that of commercial 20 wt% Pt/C as cathode electrocatalysts of passive DMFC. The polarization curves of cells with various methanol concentrations (1.5, 3.0, and 4.5 M) were recorded. The results suggested the cell with NRGO cathode could operate at higher optimum methanol concentration in contrast to the cell with Pt/C cathode. The results showed that at the same methanol concentration the maximum power density, the fuel efficiency, and the current stability for the cell with NRGO cathode are higher than those of Pt/C cathode about 208%, 269%, and 77%, respectively. Higher temperature of cathode current collector of the cell with Pt/C cathode, in spite of its lower power output, presented an evidence of oxidation of permeated methanol on its cathode surface. Also, EIS measurements clarified that COads oxidation reaction, an intermediate of methanol oxidation reaction (MOR), on cathode side of cell with Pt/C cathode implies a relatively huge impedance on the overall cell operation. By contrast, in the case of cell with NRGO cathode due to its inertness towards MOR, the overall cell impedance significantly reduced.