Highly ordered Pt alloy structures are proven effective to improve their catalytic activity and stability for the oxygen reduction reaction (ORR) for proton exchange membrane fuel cells. Here, we report a new approach to preparing ordered Pt₃Co intermetallic nanoparticles through a facile thermal treatment of Pt nanoparticles supported on Co-doped metal–organic-framework (MOF)-derived carbon. In particular, the atomically dispersed Co sites, which are originally embedded into MOF-derived carbon, diffuse into Pt nanocrystals and form ordered Pt₃Co structures. It is very crucial for the formation of the ordered Pt₃Co to carefully control the doping content of Co into the MOFs and the heating temperatures for Co diffusion. The optimal Pt₃Co nanoparticle catalyst has achieved significantly enhanced activity and stability, exhibiting a half-wave potential up to 0.92 V vs reversible hydrogen electrode (RHE) and only losing 12 mV after 30 000 potential cycling between 0.6 and 1.0 V. The highly ordered intermetallic structure was retained after the accelerated stress tests made evident by atomic-scale elemental mapping. Fuel cell tests further verified the high intrinsic activity of the ordered Pt₃Co catalysts. Unlike the direct use of MOF-derived carbon supports for depositing Pt, we utilized MOF-derived carbon containing atomically dispersed Co sites as Co sources to prepare ordered Pt₃Co intermetallic catalysts. The new synthesis approach provides an effective strategy to develop active and stable Pt alloy catalysts by leveraging the unique properties of MOFs such as 3D structures, high surface areas, and controlled nitrogen and transition metal dopings.

中文翻译：

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从有机金属骨架中还原有序的Pt ₃ Co金属间纳米粒子

事实证明，高度有序的Pt合金结构可有效提高其催化活性和质子交换膜燃料电池氧还原反应（ORR）的稳定性。在这里，我们报告了一种通过对载有Co掺杂的金属有机框架（MOF）的碳负载的Pt纳米粒子进行快速热处理来制备有序Pt ₃ Co金属间纳米粒子的新方法。特别地，原本嵌入到MOF衍生的碳中的原子分散的Co位点扩散到Pt纳米晶体中，并形成有序的Pt ₃ Co结构。对于有序的Pt ₃ Co的形成，至关重要的是要小心地控制进入MOF中的Co掺杂含量和Co扩散的加热温度。最佳Pt ₃Co纳米粒子催化剂具有显着增强的活性和稳定性，与可逆氢电极（RHE）相比，其半波电势高达0.92 V，并且在3万个电势在0.6和1.0 V之间循环后仅损失12 mV。加速应力测试后保留的原子尺寸元素映射图很明显。燃料电池测试进一步验证了有序Pt ₃ Co催化剂的高内在活性。与直接使用MOF衍生的碳载体沉积Pt不同，我们利用MOF衍生的含原子分散Co位点的碳作为Co来源来制备有序Pt ₃钴金属间催化剂。通过利用MOF的独特特性（例如3D结构，高表面积以及受控的氮和过渡金属掺杂），新的合成方法为开发活性和稳定的Pt合金催化剂提供了有效的策略。