Ultra-low Pt decorated PdFe Alloy Nanoparticles for Formic Acid Electro-oxidation

- A cost-efficient way is used to prepare transition-noble metal alloy nanoparticles.
- The Pd50Fe50/C catalyst shows excellent activity for formic acid oxidation (FAO).
- Much activity enhancement of FAO is acquired by ultra-low Pt decorated Pd50Fe50.
- A synergistic mechanism between Pt clusters and PdFe is proposed during the FAO.

Palladium (Pd), has demonstrated promising electro-catalytic activity for formic acid oxidation, but suffers from extremely low abundance. Recently alloying with a transition metal has been considered as an effective approach to reducing the loading of Pd and enhancing the activity of Pd-based catalysts simultaneously. Herein, carbon supported PdFe nanoparticles (NPs) are synthesized at room temperature by using sodium borohydride as reducing agent and potassium ferrocyanide as Fe precursor. The Pd50Fe50 alloy sample annealed at 900 °C for 1 h shows the best catalytic activity among PdxFe1-x (x = 0.2, 0.4, 0.5, 0.6, and 0.8) towards formic acid oxidation. To further improve both catalytic activity and stability, the ultra-low Pt (0.09 wt %) decorated Pd50Fe50 NPs (PtPd/PdFe) are prepared via the galvanic replacement reaction. Compared with Pd50Fe50/C, the PtPd/PdFe/C Exhibits 1.52 times higher catalytic activity and lower onset potential (−0.12 V). The significant enhancements of formic acid oxidation can be attributed to the accelerated dehydrogenation reaction of formic acid by Pt atomic clusters. Moreover, the PtPd/PdFe/C also demonstrates better tolerance to poisons during formic acid oxidation.