Sulfonated polypyrrole matrix induced enhanced efficiency of Ni nanocatalyst for application as an anode material for DMFCs

Search for new catalyst (in place of traditionally used high cost Pt-Ru metal alloy) and catalyst supporting matrix (in place of conventionally used low efficient Vulcan carbon) for oxidation of methanol and application as anode catalyst system in direct methanol fuel cells (DMFCs) has been an active area of research for last several years. This work demonstrates utilization of comparatively less expensive and more abundant Ni metal catalyst, supported on polypyrrole (PPy) and partially sulfonated PPy (SPPy), as potential catalyst systems in place of the commercially used Pt-Ru/C catalyst system for oxidation of methanol. SPPy emerged as the best matrix for the Ni catalyst nanoparticles, in terms of catalyst deposition, dispersion, distribution and utilization. This combination generated a peak current density of 359 μAcm^-2 at +0.579 V, as well as, a higher I_F/I_B ratio compared to the commercial Pt-Ru/C catalyst. In addition, Ni/SPPy produced a current density of 144.5 mAcm^-2 (at +0.2 V potential) and a maximum power density of 28.9 mWcm^-2 at 60 °C when utilized as an anode catalyst system in DMFC. The results, thus obtained, were far better than that exhibited by the commercial Pt-Ru/C, as well as, the Ni/PPy catalyst systems.