Synthesis and Design of a Highly Stable Platinum Nickel Electrocatalyst for the Oxygen Reduction Reaction

Exploring effective, stable, and affordable oxygen reduction reaction (ORR) catalysts is very significant for the practical application of proton-exchange membrane fuel cells. In this work, a facile and expandable method is developed to prepare ultrathin PtNi nanowires (NWs) with various Pt/Ni contents, and the ORR performance of the synthesized samples is thoroughly investigated. Pt_3.2Ni NWs show the best ORR performance among the studied samples and, notably, exhibit much better ORR activity and stability than those of the Pt/C catalyst even after a 300,000-continuous cycling test. This work confirms that the initial Pt/Ni ratio plays a critical role in the ORR activity and stability of PtNi NWs, and the structure of the PtNi NWs can be well retained after the durability test. Additionally, the structure and performance of Pt_3.2Ni NWs are investigated in detail during various cycles, and the performance decay is attributed to the dealloying of Ni and the corrosion of the one-dimensional structure after a prolonged durability test. This work provides a desirable method for rationally synthesizing a highly efficient ORR electrocatalyst with remarkable stability.