Bimetallic Pd–Zn nanoalloys supported on Vulcan XC-72R carbon as anode catalysts for oxidation process in formic acid fuel cell

• Vulcan carbon was chemical treatment for the best nanoalloys distribution and size.
• The sonochemical process was used for the PdnZn nanoalloys synthesis.
• Nanocatalysts were investigated for electrochemical oxidation of formic acid.
• The nanocatalysts performance was evaluated by CV, LSV, DPV and CHA.
• PdnZn/VC has higher activity and durability for formic acid oxidation than Pd/VC.

This work reports the synthesis of palladium-based nanoalloys of zinc in different atomic ratio via a sonochemical process and investigation of their activities for formic acid electro-oxidation. The bimetallic nanoalloys are characterized by powder X-ray diffractometry (XRD) and inductively coupled plasma-atomic emission spectroscopy (ICP-AES) to determine their crystal structures and elemental compositions. Alloy formation of the nanocatalysts is proven by energy dispersive x-ray spectroscopy line profiles using field emission scanning electron microscopy (FESEM). The PdnZn/VC catalysts (1 ≤ n ≤ 3) showed better performance for the anodic oxidation of formic acid than Pd/VC. Activities based on the current densities are in the order of Pd2Zn > Pd3Zn > Pd1Zn. Compared with Pd/VC catalyst, the anodic peak potential of formic acid shifted toward negative value by ∼30 mV at the Pd2Zn/C catalyst electrode. Pd2Zn/VC also exhibits high stability, suggesting that this bimetallic alloy is a good candidate for the formic acid fuel cell.