High‐Performance Ordered PdCuFe/C Intermetallic Catalyst for Electrochemical Oxygen Reduction in Proton Exchange Membrane Fuel Cells

Abstract The phase state of nanoparticles plays a pivotal role in regulating the electronic structure of Pd to enhance the catalytic performance and durability for the oxygen reduction reaction (ORR). To elucidate the correlation of the electronic structure with activity, a series of body‐centered cubic (bcc) PdCu/C, PdCuFe/C, and PdCuCo/C intermetallic compounds were fabricated by using an impregnation reduction method followed by annealing. The results of rotating disk electrode studies show that the structurally ordered PdCuFe/C nanoparticles exhibit a much larger increase in mass activity (0.08 A mg Pd −1 ), about 2.1 and 5 times higher than ordered PdCuCo/C and PdCu/C, respectively. More importantly, the maximum power density of the ordered PdCuFe/C was 267 mW cm −2 in proton exchange membrane fuel cells. The X‐ray photoelectron spectroscopy results revealed that that the addition of Fe into PdCu/C can efficiently regulate the electronic structure of Pd in optimizing the oxygen binding energy for the ORR. Our work provides a general approach to enhance Pd‐based ternary alloy catalysts with Pt‐like catalytic activity for fuel cell applications.