Rapid Microwave-Assisted Solvothermal Synthesis of Methanol Tolerant Pt-Pd-Co Nanoalloy Electrocatalysts

We report here a microwave-assisted solvothermal (MW-ST) method to synthesise carbon-supported multimetallic nanostructured alloys of Pt, Pd and Co with high crystallinity and homogeneity for electrocatalytic application in fuel cells. Multimetallic nanoalloy electrocatalysts have been synthesised by a one-pot, rapid MW-ST method within 15 min at <300 degrees C without any post-annealing in reducing gas atmospheres. For a comparison, same multimetallic alloys were also synthesised by heat treatment of co-precipitated metals. Significant differences were observed in the phase structure and surface composition of the alloys synthesised by the two methods, which were rationalised based on the synthesis procedures adopted. Further, the multimetallic alloys were also explored for their electrocatalytic applications as cathode catalysts for oxygen reduction reaction (ORR). The multimetallic alloys, synthesised by the MW-ST method, show much higher ORR activity compared to their counterparts synthesised by the conventional borohydride reduction method. While the ORR activity of Pt70Pd20Co10 is comparable to that of commercial Pt, the OR.R activity of Pt50Pd30Co20 in direct methanol fuel cells (DMFC) is superior to that of commercial Pt at high methanol concentrations due to its high tolerance to methanol that may crossover from the anode to the cathode.