Surfactant-free room temperature synthesis of PdxPty/C assisted by ultra-sonication as highly active and stable catalysts for formic acid oxidation.

Formic acid oxidation is usually catalyzed on PdPt bimetallic catalysts, which are synthesized by co-reduction of noble metal precursors in the presence of high molecular capping agents. In this work, surfactant-free Pd x Pt y /C catalysts are synthesized by H 2 reduction in ethylene glycol assisted with ultrasonication vibration at room temperature. Nanoparticle agglomeration in the course of preparation has been sufficiently curbed by strong mechanical ultrasonication instead of traditionally-employed surfactants. As a result, "clean" surfactant-free Pd x Pt y /C catalysts necessitate only simple washing before collection. The catalysts are characterized by transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The compositionally optimized Pd 100 Pt 1 /C catalyst registers a mass activity of 3171 A g−1 (Pt + Pd) for formic acid oxidation in 0.5 M H 2 SO 4 +0.5 M HCOOH, which lists one of the best results reported so far and surpasses that of a commercial Pd/C by 5.6 times. Stability of the catalysts is investigated by cyclic voltammetric as well as chronoamperometric evaluations. This work offers a convenient and environmentally benign room-temperature route to synthesize highly active and stable catalysts for formic acid oxidation. Surfactant-free Pd x Pt y /C catalysts are synthesized by H 2 reduction in ethylene glycol assisted with ultrasonication vibration at room temperature. Nanoparticle agglomeration has been sufficiently curbed by strong mechanical ultrasonication instead of traditionally-employed surfactants. Image 1 • "Clean" Pd x Pt y /C are synthesized by H 2 reduction assisted with ultrasonication. • Optimized Pd 100 Pt 1 /C catalyst registers a mass activity of 3171 A g−1 for FAO. • Cavitation and reduced skin friction by ultrasound contributed to uniform particles. • Mass activity ranks one of the best results in literature. [ABSTRACT FROM AUTHOR]