Degradation of polymer electrolyte membrane fuel cell (PEMFC) systems has emerged as a critical issue. A thin metal oxide layer coated with Pt/carbon via ALD (atomic layer deposition) is one of the potential approaches for preserving electrochemical activity; however, the exact interfacial effects of metal oxide on enhancing PEMFC durability are unclear. Herein, interfacial engineering of the TiO₂ layers within the in situ-synthesized Pt/carbon catalysts (Pt/TiO₂/C and TiO₂/Pt/C) was studied using fluidized bed reactor (FBR) ALD to investigate the exact effects of the catalysts. For the Pt/TiO₂/C catalyst, the TiO₂ layer was first conformally coated on the carbon surfaces, whereas for TiO₂/Pt/C, the TiO₂ layer was selectively formed on the Pt NP surface via the ALD mechanism. The Pt/TiO₂/C catalyst has a higher Pt loading with suppressed micropores due to the introduction of the TiO₂ layer on the carbon support, whereas the TiO₂/Pt/C catalyst remained in the 2–3 nm mesopores. The electrochemical durability of both ALD catalysts is superior to that of the commercial Pt catalyst. Encapsulating the TiO₂ layer on the Pt surface specializing in blocking Pt dissolution resulted in better long-term stability of the electrochemical characteristics compared to the stability of those of Pt/TiO₂/C, which especially showed the better initial performance of the electrochemically active surface area, oxygen reduction reaction, and PEMFC single-cell performance. This study provides the direction and steps toward an efficient nanostructure design of metal oxide by ALD in most catalyst fields.

中文翻译：

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通过原子层沉积将金属氧化物保护层原位工程转化为 Pt/碳燃料电池催化剂

聚合物电解质膜燃料电池 (PEMFC) 系统的降解已成为一个关键问题。通过 ALD（原子层沉积）涂覆 Pt/碳的薄金属氧化物层是保持电化学活性的潜在方法之一。然而，金属氧化物对增强 PEMFC 耐久性的确切界面影响尚不清楚。在此，使用流化床反应器 (FBR) ALD 研究了原位合成的 Pt/碳催化剂（Pt/TiO ₂ /C 和 TiO _{2 /Pt/C）中 TiO 2}层的界面工程，以研究催化剂。对于 Pt/TiO ₂ /C 催化剂，首先将 TiO ₂层保形涂覆在碳表面上，而对于 TiO ₂/Pt/C，TiO ₂层通过ALD机制选择性地形成在Pt NP表面上。_{由于在碳载体上引入了 TiO 2}层，Pt/TiO ₂ /C 催化剂具有更高的 Pt 负载量和抑制的微孔，而 TiO ₂ /Pt/C 催化剂保留在 2-3 nm 中孔中。两种 ALD 催化剂的电化学耐久性均优于商业 Pt 催化剂。_{与 Pt/TiO 2的稳定性相比，将 TiO 2}层包封在Pt 表面专门用于阻止 Pt 溶解导致电化学特性的长期稳定性更好/C，尤其表现出更好的电化学活性表面积、氧还原反应和PEMFC单电池性能的初始性能。本研究为在大多数催化剂领域通过 ALD 设计金属氧化物的有效纳米结构提供了方向和步骤。