Liu Xuan, Wang Yuhan, He Hu, Zhao Zhonglong, Luo Xuan, Zhang Siyang, Lu Gang, Su Dong, Wang Yucheng, Huang Yunhui, Li Qing
State Key Laboratory of Material Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, China.
National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China.
Nat Commun. 2025 May 27;16(1):4895. doi: 10.1038/s41467-025-60171-z.
The long-standing challenges facing Pt-based alloy catalysts in oxygen reduction reactions (ORRs) are rapid oxidation and loss of transition metal/Pt in proton exchange membrane fuel cells (PEMFCs). In this work, we report a concept of "covalentization" in intermetallic L1-PtMM' (M = Fe, Co, Ni and M' = one of the 4-period elements (from Ti to Ge)) alloys to enhance their electrochemical stability. Specifically, the formation of a quasi-covalent bond network in L1-PtMM' due to the less occupied antibonding states induced by high d-band positions of M' elements (e.g., Ti, V, Cr) enhances atomic bond order and strength, diminishing Co anodic dissolution via strengthened Pt/Co-M' bonds and reducing Co cathodic corrosion by inhibiting Pt oxidation through an electron buffering effect. The developed L1-PtCoCr/C catalysts show a high mass activity (MA = 1.27 A mg) and rated power (16.5 W mg) in PEMFCs at a low total Pt loading of 0.075 mg cm. The catalysts also exhibit high electrochemical stability with ~3% and 5% loss of MA and rated power after 30,000 accelerated durability testing cycles and projects a lifetime of about 42,000 hours.
基于铂的合金催化剂在氧还原反应（ORR）中面临的长期挑战是质子交换膜燃料电池（PEMFC）中过渡金属/铂的快速氧化和损失。在这项工作中，我们报道了一种在金属间化合物L1-PtMM'（M = Fe、Co、Ni，M' = 第四周期元素（从Ti到Ge）之一）合金中的“共价化”概念，以提高其电化学稳定性。具体而言，由于M'元素（如Ti、V、Cr）的高d带位置诱导的未占据反键态较少，在L1-PtMM'中形成了准共价键网络，增强了原子键级和强度，通过加强Pt/Co-M'键减少了Co的阳极溶解，并通过电子缓冲效应抑制Pt氧化来减少Co的阴极腐蚀。所开发的L1-PtCoCr/C催化剂在总铂负载量低至0.075 mg cm的PEMFC中显示出高的质量活性（MA = 1.27 A mg）和额定功率（16.5 W mg）。在30000次加速耐久性测试循环后，该催化剂还表现出高的电化学稳定性，质量活性和额定功率损失约3%和5%，预计使用寿命约为42000小时。
