Liu Jieyuan, Liu Shiyuan, Yan Fangzheng, Wen Zishu, Chen Weiwei, Liu Xiaofang, Liu Qingtao, Shang Jiaxiang, Yu Ronghai, Su Dong, Shui Jianglan
School of Materials Science and Engineering, Beihang University, Beijing 100191, P. R. China.
Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
J Am Chem Soc. 2022 Oct 19;144(41):19106-19114. doi: 10.1021/jacs.2c08361. Epub 2022 Oct 5.
It remains a challenge for platinum-based oxygen reduction reaction catalysts to simultaneously possess high mass activity and high durability in proton-exchange-membrane fuel cells. Herein, we report ultrathin holey nanotube (UHT)-structured Pt-M (M = Ni, Co) alloy catalysts that achieve unprecedented comprehensive performance. The nanotubes have ultrathin walls of 2-3 nm and construct self-supporting network-like catalyst layers with thicknesses of less than 1 μm, which have efficient mass transfer and 100% surface exposure, thus enabling high utilization of Pt atoms. Combined with the high intrinsic activity produced by the alloying effect, the catalysts achieve high mass activity. Moreover, the nanotube structure not only avoids the agglomeration problem of nanoparticles, but the low curvature of the tube wall also gives UHT a low surface energy (less than 1/3 of that of the same size nanoparticle), so UHT is more resistant to the Ostwald ripening and is stable. For the first time, the U.S. DOE mass activity target and dual durability targets for load and start-stop cycles are achieved on one catalyst. This study provides an effective structural strategy for the preparation of electrocatalysts with high atomic efficiency and excellent durability.
对于质子交换膜燃料电池中的铂基氧还原反应催化剂而言，要同时具备高质量活性和高耐久性仍然是一项挑战。在此，我们报道了具有超薄多孔纳米管（UHT）结构的Pt-M（M = Ni、Co）合金催化剂，其实现了前所未有的综合性能。这些纳米管具有2-3纳米的超薄管壁，并构建了厚度小于1微米的自支撑网络状催化剂层，具有高效的传质和100%的表面暴露率，从而实现了Pt原子的高利用率。结合合金化效应产生的高本征活性，这些催化剂实现了高质量活性。此外，纳米管结构不仅避免了纳米颗粒的团聚问题，而且管壁的低曲率也赋予UHT低表面能（小于相同尺寸纳米颗粒的1/3），因此UHT更耐奥斯特瓦尔德熟化且稳定。首次在一种催化剂上实现了美国能源部的质量活性目标以及负载和启停循环的双重耐久性目标。这项研究为制备具有高原子效率和优异耐久性的电催化剂提供了一种有效的结构策略。
