Microfluidic reactor technology has been developed in chemical synthesis due to their unique characteristics, such as enhanced mixing for reactants, rapid reactions, rapid heat transfer, precise control, and safe operational environment. Ordered intermetallic nanomaterials are of great interest for fuel cells due to their unique electronic and structural properties. Traditionally, synthesis of intermetallic compounds requires high-temperature and long time processes. Developing rapid, phase- and size- controlled synthesis techniques is still a great challenging issue. The performance of electrocatalystes remarkably depends on their physical and chemical properties relative to particle structures, morphologies and surface effects, and therefore their synthesis requires superior control of reactions. Fortunately microfluidics reactors can cater to the requirement for size-, shape-, and structure-controlled syntheses. In this study we explore the approach of microfluidic systems to synthesize intermetallic nanoparticles (NPs) utilizing its feature of superior control of reactions. PtBi2 intermetallic compound is one of the promising candidates of direct methanol fuel cell catalysts because of its high catalytic activity and excellent methanol tolerance property. Here we proposed a one-step, facile and ultrafast, phase- and size- controlled process for synthesizing ordered Pt-Bi intermetallic NPs in microfluidic reactors in seconds. Single-phase PtBi and PtBi2 intermetallic NPs were prepared by tuning the reaction temperature and size-controlling was achieved through the changing of solvents. The as-prepared Pt1Bi2 intermetallic NPs from PEG600 were selected and loaded on the XC-72 carbon support to act as an electrocatalyst for DMFCs, and the electrochemistry performance showed the mass current densities of PtBi/XC-72 is 185.6 mA/mgPt at 300 mV, which is 1.7 times higher than that of commercial Pt/C (110.9 mA/mgPt) although this value is lower than nanotubed supported Pt catalyst. The results show Pt1Bi2/XC-72 catalysts possess significant enhancement of the ORR electrocatalytic activity and excellent methanol tolerance capacity compared to those of commercial Pt/C.

Synthesis of Pt-based catalysts for DMFCs by microfluidic reactors

249th National Meeting (2015)

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