One-Step, Facile and Ultrafast Synthesis of Phase- and Size-Controlled Pt–Bi Intermetallic Nanocatalysts through Continuous-Flow Microfluidics

Ordered intermetallic nanomaterials are of considerable interest for fuel cell applications because of their unique electronic and structural properties. The synthesis of intermetallic compounds generally requires the use of high temperatures and multiple-step processes. The development of techniques for rapid phase- and size-controlled synthesis remains a formidable challenge. The intermetallic compound Pt₁Bi₂ is a promising candidate catalyst for direct methanol fuel cells because of its high catalytic activity and excellent methanol tolerance. In this work, we explored a one-step, facile and ultrafast phase- and size-controlled process for synthesizing ordered Pt–Bi intermetallic nanoparticles (NPs) within seconds in microfluidic reactors. Single-phase Pt₁Bi₁ and Pt₁Bi₂ intermetallic NPs were prepared by tuning the reaction temperature, and size control was achieved by modifying the solvents and the length of the reaction channel. The as-prepared Pt–Bi intermetallic NPs exhibited excellent methanol tolerance capacity and high electrocatalytic activity. Other intermetallic nanomaterials, such as Pt₃Fe intermetallic nanowires with a diameter of 8.6 nm and Pt₁Sn₁ intermetallic nanowires with a diameter of 6.3 nm, were also successfully synthesized using this method, thus demonstrating its feasibility and generality