Transition metal doping enhancing structural ordering and catalytic performance of Pt-Ni alloy for oxygen reduction reaction

The construction of ordered Pt-based intermetallic compounds (IMCs) has emerged as an effective approach to improve the activity and durability of catalysts for the oxygen reduction reaction. However, the synthesis, especially for Pt-Ni IMCs, is often hindered by their low disorder-order phase transformation temperatures ( T PT ). Here, we report a general synthetic strategy by introducing transition metals (M = Ti, V, Cr, Mn, and Fe) capable of forming high- T PT (≥1000 °C) PtM IMCs, which can effectively elevate the T PT of Pt 3 Ni and PtNi alloys and promote their ordering degree. In situ high-temperature X-ray diffraction (HT-XRD) results confirm that Ti doping greatly increases the T PT of Pt 3 Ni from 490 to over 800 °C, enabling the formation of the ordered IMCs. The optimized Pt 3 Ni 0.7 Ti 0.3 catalyst achieves mass activity and specific activity of 1.35 A mg Pt −1 and 1.78 mA cm −2 , respectively, higher than those of Pt/C and Pt 3 Ni, while holding high stability. This work establishes a broadly applicable strategy for the synthesis of Pt-based IMCs, offering a pathway to durable, high-performance fuel-cell catalysts.