Wang Zhida, Mai Yilang, Yang Yi, Shen Lisha, Yan Changfeng
Hydrogen Production and Utilization Lab, CAS Key Laboratory of Renewable Energy, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640, China.
Guangdong Key Laboratory of New and Renewable Energy Research and Development, Guangzhou 510640, China.
ACS Appl Mater Interfaces. 2021 Aug 18;13(32):38138-38146. doi: 10.1021/acsami.1c04259. Epub 2021 Aug 6.
Designing Pt-based nanoparticle (NP) catalysts is of great interest for the lowering of Pt usage and the enhancement of catalytic activity on the proton-exchange membrane fuel cells (PEMFCs). However, it is still challenging to develop well-arrayed catalyst NPs on supports over multiple-length scales. Herein, we presented a facile strategy of producing well-ordered Pt-based NPs toward oxygen reduction reaction (ORR) catalysts assisted by the self-assembly of block copolymers. In contrast to the conventional Pt/C ORR catalysts with a random dispersion on carbon, the as-prepared Pt, PtCo, and PtCo@Pt NPs in our work were hexagonally arranged with a uniform quasi-spherical shape and ordered distribution. The systematic study related to their ORR activities revealed that the PtCo@Pt core-shell NP arrays were more active and more durable than PtCo, Pt, and the commercial Pt/C catalyst. In the rotating-disk electrode test, a half-wave potential () of 0.86 V versus RHE and a 4-e ORR mechanism were found for PtCo@Pt. Single-cell performance showed that the current density and the peak power density of PtCo@Pt achieved 0.86 A/cm@0.7 V and 1.05 W/cm, respectively, with a Pt loading of ∼0.15 mg/cm on the cathode. Also, they held 81.4 and 82.9% retention, respectively, after the durability test in the single-cell test. Density functional theory calculation results revealed that PtCo@Pt NPs had a lower d-band center and a weaker oxygen binding energy compared to Pt and PtCo, which contributed to the enhancement of the ORR activity.
设计基于铂的纳米颗粒（NP）催化剂对于降低铂的用量以及提高质子交换膜燃料电池（PEMFC）的催化活性具有重要意义。然而，在多个长度尺度上在载体上开发排列良好的催化剂NP仍然具有挑战性。在此，我们提出了一种简便的策略，通过嵌段共聚物的自组装来制备用于氧还原反应（ORR）催化剂的有序排列的基于铂的NP。与在碳上随机分散的传统Pt/C ORR催化剂相比，我们工作中制备的Pt、PtCo和PtCo@Pt NP呈六边形排列，具有均匀的准球形形状和有序分布。对其ORR活性的系统研究表明，PtCo@Pt核壳NP阵列比PtCo、Pt和商业Pt/C催化剂更具活性和耐久性。在旋转圆盘电极测试中，PtCo@Pt的半波电位（）相对于RHE为0.86 V，并且发现其具有4电子ORR机制。单电池性能表明，PtCo@Pt的电流密度和峰值功率密度分别在阴极上铂负载量约为0.15 mg/cm时达到0.86 A/cm@0.7 V和1.05 W/cm。此外，在单电池测试中的耐久性测试后，它们分别保持了81.4%和82.9%的保留率。密度泛函理论计算结果表明，与Pt和PtCo相比，PtCo@Pt NP具有更低的d带中心和更弱的氧结合能，这有助于提高ORR活性。
