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

Abstract

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 °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 ORR 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.

Synthesis of Pd3Co1@Pt/C Core‐Shell Catalysts for Methanol‐Tolerant Cathodes of Direct Methanol Fuel Cells

“…There are few works in the literature that report the performance under realistic conditions in a DMFC of Pd‐based cathodes. The performance obtained in this work using a total Pt loading in the cell as low as 0.56 mg cm −2 (0.5 mg cm −2 at the anode and 0.06 mg cm −2 at the cathode) are comparable to those obtained when using a similar composition but a Pt loading of 2.5 mg cm −2 29…”

“…The performance obtained in this work using a total Pt loading in the cell as low as 0.56 mg cm À2 (0.5 mg cm À2 at the anode and 0.06 mg cm À2 at the cathode) are comparable to those obtained when using a similar composition but a Pt loading of 2.5 mg cm À2 . [29] Conclusion Pd-based catalysts usually present lower catalytic activity than their Pt-based counterparts in DMFCs. The use of a composite Pd-Pt catalyst with a very low Pt content (5 wt.…”

Fast microwave-assisted solvothermal synthesis of metal nanoparticles (Pd, Ni, Sn) supported on sulfonated MWCNTs: Pd-based bimetallic catalysts for ethanol oxidation in alkaline medium

“…Microwave method is highly advantageous over the conventional borohydride reduction methods; the reaction mechanism of microwave methodology is described elsewhere [28,30]. The MWAS method provides a uniform nucleation environment and offers highly crystalline monodispersed metal nanoparticles.…”

“…The microwave-assisted solvothermal synthesis (MWAS) is an attractive synthetic strategy for the preparation of nanosized catalysts [26][27][28]. It is faster, cleaner, simpler than the conventional borohydride reduction methods [26][27][28]. For example, Manthiram and co-workers [28] recently reported that alloys, synthesised by the MWAS strategy, enhanced electrocatalytic reduction of oxygen compared to their counterparts synthesised by the conventional borohydride reduction method.…”

“…The microwave-assisted solvothermal synthesis (MWAS) is an attractive synthetic strategy for the preparation of nanosized catalysts [26][27][28]. It is faster, cleaner, simpler than the conventional borohydride reduction methods [26][27][28].…”