Fabrication of nano-platinum alloy electrocatalysts and their performance in a micro-direct methanol fuel cell

The main target of this investigation is to propose an effective anodic electrocatalyst for micro-direct methanol fuel cell. For this purpose, five nanostructured metal alloy electrocatalysts including platinum (Pt), ruthenium (Ru) and iron (Fe) are synthesized. The single-walled and multi-walled carbon nanotubes (SW-CNT and MW-CNT) and graphene (Gr) are employed as the carbon (C) base. First, PtRuFe/SW-CNT, PtRuFe/MW-CNT, PtRuFe/Gr and PtRuFe/C catalysts with a 1:4:5 atomic ratio for Pt, Ru and Fe, respectively, and PtRu/C catalyst with a 1:1 atomic ratio for Pt and Ru, correspondingly, are prepared by the process of improved alcohol recovery. In continuation, the morphology and activity of synthesized nano-electrocatalysts are confirmed and assessed by applying the physical and electrochemical tests. According to the obtained results, PtRuFe/SW-CNT is the most suitable catalyst for methanol oxidation reaction. The outcomes of electrochemical measurements show that PtRuFe/SW-CNT electrocatalyst has the highest activity, mass activity, mass transfer and electrochemical active surface area with respect to methanol oxidation in comparison with the commercial Pt/C and the rest of the synthesized catalysts. Next, two-electrode membrane assembly is fabricated with PtRuFe/SW-CNT and commercial Pt/C electrocatalysts to evaluate the performance of them in micro-direct methanol fuel cell. Based on the obtained polarization curves, by using PtRuFe/SW-CNT instead of commercial Pt/C, the current density in zero-voltage and maximum power density enhance by 48% and 92.3%, respectively.