Supported platinum intermetallic compound catalysts have attracted considerable attention owing to their remarkable activities and durability for the oxygen reduction reaction in proton-exchange membrane fuel cells. However, the synthesis of highly ordered intermetallic compound catalysts remains a challenge owing to the limited understanding of their formation mechanism under high-temperature conditions. In this study, we perform in-situ high-temperature X-ray diffraction studies to investigate the structural evolution in the impregnation synthesis of carbon-supported intermetallic catalysts. We identify the phase-transition-temperature (T_PT)-dependent evolution process that involve concurrent (for alloys with high T_PT) or separate (for alloys with low T_PT) alloying/ordering stages. Accordingly, we realize the synthesis of highly ordered intermetallic catalysts by adopting a separate annealing protocol with a high-temperature alloying stage and a low-temperature ordering stage, which display a high mass activity of 0.96 A mg_Pt^–1 at 0.9 V in H₂–O₂ fuel cells and a remarkable durability.

负载型铂金属间化合物催化剂由于其在质子交换膜燃料电池中氧还原反应的卓越活性和耐久性而引起了广泛关注。然而，由于对高温条件下金属间化合物形成机制的了解有限，高度有序金属间化合物催化剂的合成仍然是一个挑战。在本研究中，我们进行原位高温 X 射线衍射研究，以研究碳负载金属间催化剂浸渍合成中的结构演变。我们确定了相变温度 ( T _PT ) 相关的演化过程，其中涉及并发（对于具有高T _PT的合金）或单独（对于具有低T _PT的合金）合金化/排序阶段。因此，我们通过采用具有高温合金化阶段和低温有序阶段的单独退火方案，实现了高度有序金属间催化剂的合成，该催化剂在 H 中 0.9 V 时表现出 0.96 A mg _Pt ^–1的高质量活性₂ –O ₂燃料电池具有卓越的耐用性。