Enhanced catalytic activity of ternary Pd-Ni-Ir nanoparticles supported on carbon toward formic acid electro-oxidation

Aiming to further promote the performance of PdNi for formic acid electro-oxidation (FAEO), ternary Pd-Ni-Ir/C nanocatalyst was synthesized via an ethylene glycol-assisted NaBH4 reduction process. The physical characterizations show that the PdNiIr nanoparticles with a small mean size are well dispersed on carbon support. The electrochemical measurements demonstrate that the PdNiIr/C catalyst exhibits the highest activity for FAEO. The onset and peak potential of FAEO on PdNiIr/C is about 70 mV more negative than that on the Pd/C and PdNi/C catalysts. The mass activity of Pd in PdNiIr/C at 0.14 V is 2830 mA mg(-1) (Pd), which is about 1.65, 1.82, and 2.2 times as high as that of PdIr/C, PdNi/C, and Pd/C, respectively. The enhancement should be attributed to the electronic effect and bi-functional mechanism.