Ma Yanling, Peng Jiaheng, Tian Jiakang, Gao Wenpei, Xu Jialiang, Li Fan, Tieu Peter, Hu Hao, Wu Yi, Chen Wenlong, Pan Lei, Shang Wen, Tao Peng, Song Chengyi, Zhu Hong, Pan Xiaoqing, Deng Tao, Wu Jianbo
State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, P. R. China.
Department of Materials Science and Engineering, University of California, Irvine, 5200 Engineering Hall, Irvine, CA 92697, USA.
Sci Adv. 2024 Oct 18;10(42):eado4935. doi: 10.1126/sciadv.ado4935.
Shape-controlled alloy nanoparticle catalysts have been shown to exhibit improved performance in the oxygen reduction reaction (ORR) in liquid half-cells. However, translating the success to catalyst layers in fuel cells faces challenges due to the more demanding operation conditions in membrane electrode assembly (MEA). Balancing durability and activity is crucial. Here, we developed a strategy that limits the atomic diffusion within surface layers, fostering the phase transition and shape retention during thermal treatment. This enables selective transformation of platinum-iron nanowire surfaces into intermetallic structures via atomic ordering at a low temperature. The catalysts exhibit enhanced MEA stability with 50% less Fe loss while maintaining high catalytic activity comparable to that in half-cells. Density functional calculations suggest that the ordered intermetallic surface stabilizes morphology against rapid corrosion and improves the ORR activity. The surface engineering through atomic ordering presents potential for practical application in fuel cells with shape-controlled Pt-based alloy catalysts.
形状可控的合金纳米颗粒催化剂已被证明在液体半电池中的氧还原反应（ORR）中表现出更高的性能。然而，由于膜电极组件（MEA）中要求更高的操作条件，将这种成功转化为燃料电池中的催化剂层面临挑战。平衡耐久性和活性至关重要。在这里，我们开发了一种策略，该策略限制了表面层内的原子扩散，促进了热处理过程中的相变和形状保留。这使得铂铁纳米线表面能够通过低温下的原子有序化选择性地转变为金属间化合物结构。这些催化剂表现出增强的MEA稳定性，铁损失减少50%，同时保持与半电池中相当的高催化活性。密度泛函计算表明，有序的金属间化合物表面使形态稳定，防止快速腐蚀，并提高了ORR活性。通过原子有序化进行的表面工程为形状可控的铂基合金催化剂在燃料电池中的实际应用提供了潜力。
