Kim Danah, Lim Jihoon, Lee Ji Hee, Choi Joohee, Kwon Sung Hyun, Yim Sung-Dae, Sohn Young-Jun, Lee Seung Geol
School of Chemical Engineering, Pusan National University, Busan 46241, Republic of Korea.
Research Institute of Industrial Technology, Pusan National University, Busan 46241, Republic of Korea.
ACS Omega. 2023 Aug 9;8(35):31801-31810. doi: 10.1021/acsomega.3c02886. eCollection 2023 Sep 5.
For the widespread adoption of polymer electrolyte membrane fuel cells, it is compelling to investigate the influence of the Pt nanoparticle shapes on the electrocatalytic activity. In this study, a catalyst layer was modeled by incorporating four types of Pt nanoparticles: tetrahedron, cube, octahedron, and truncated octahedron, to investigate the relationship between the shapes of the nanoparticles and their impact on the oxygen transport properties using molecular dynamics simulations. The results of our study reveal that the free volume, which has a substantial impact on the oxygen transport properties, exhibited higher values in the sequence of the tetrahedron, cube, octahedron, and truncated octahedron model. The difference in free volume following the formation of less dense ionomers was also related to the surface adsorption of Pt nanoparticles. Consequently, this led to an improved facilitation of oxygen transport. To clarify the dependence of the oxygen transport on the shape of the Pt nanoparticles in detail, we analyzed the structural properties of different Pt shapes by dividing the Pt nanoparticle regions into corners, edges, and facets. Examination of the structural properties showed that the structure of the ionomer depended not only on the shape of the Pt nanoparticles but also on the number of corners and edges in the upper and side regions of the Pt nanoparticles.
为了使聚合物电解质膜燃料电池得到广泛应用，研究铂纳米颗粒形状对电催化活性的影响显得尤为迫切。在本研究中，通过纳入四种类型的铂纳米颗粒（四面体、立方体、八面体和截顶八面体）对催化剂层进行建模，以利用分子动力学模拟研究纳米颗粒形状与其对氧传输特性影响之间的关系。我们的研究结果表明，对氧传输特性有重大影响的自由体积在四面体、立方体、八面体和截顶八面体模型序列中呈现出更高的值。形成密度较小的离聚物后自由体积的差异也与铂纳米颗粒的表面吸附有关。因此，这导致了氧传输促进作用的改善。为了详细阐明氧传输对铂纳米颗粒形状的依赖性，我们通过将铂纳米颗粒区域划分为角、边和面来分析不同铂形状的结构特性。对结构特性的研究表明，离聚物的结构不仅取决于铂纳米颗粒的形状，还取决于铂纳米颗粒上部和侧面区域的角和边的数量。
