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Ordered Intermetallic PtCu Catalysts Made from Pt@Cu Core/Shell Structures for Oxygen Reduction Reaction
Inorganic Chemistry ( IF 4.3 ) Pub Date : 2022-09-12 , DOI: 10.1021/acs.inorgchem.2c02501
Xuxu Ye 1 , Ru-Yang Shao 1 , Peng Yin 1 , Hai-Wei Liang 1 , Yan-Xia Chen 1
Inorganic Chemistry ( IF 4.3 ) Pub Date : 2022-09-12 , DOI: 10.1021/acs.inorgchem.2c02501
Xuxu Ye 1 , Ru-Yang Shao 1 , Peng Yin 1 , Hai-Wei Liang 1 , Yan-Xia Chen 1
Affiliation
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Platinum-based ordered intermetallic compounds are promising low-Pt catalysts toward the oxygen reduction reaction (ORR) for high-performance fuel cells. However, the synthesis of ordered intermetallic catalysts usually requires high-temperature annealing to overcome the energy barrier for atom diffusion, which leads to inevitable sintering of catalysts and greatly reduced mass-specific activity. Herein, we developed a new strategy to synthesize PtCu-ordered intermetallic catalysts by the generation of the Pt@Cu core/shell nanoparticles (Pt@Cu NPs) by Pt-assisted H2 reduction of Cu2+ with subsequent annealing at 500–1000 °C. Compared to the commonly used wet-impregnation method, the core/shell structure starts to form ordered PtCu alloys at a lower annealing temperature (500 °C). The Pt@Cu core/shell structure avoids the necessary process of Cu atoms diffusing to Pt NPs across the carbon supports occurred during high-temperature annealing in the wet-impregnation method, which ensures the formation of PtCu NPs with higher ordering degree while annealing at the same temperature. The highly ordered small-sized PtCu catalysts prepared by the core/shell strategy exhibit higher mass activity and specific activity compared to those prepared by the wet-impregnation method. Moreover, a positive correlation between the ORR activity and the ordering degree of the intermetallic PtCu NPs is identified, which could be associated with the increase of compressive strain with the ordering degree.
中文翻译：
由 Pt@Cu 核/壳结构制成的用于氧还原反应的有序金属间化合物 PtCu 催化剂
铂基有序金属间化合物是用于高性能燃料电池的氧还原反应 (ORR) 的有前途的低 Pt 催化剂。然而，有序金属间化合物催化剂的合成通常需要高温退火来克服原子扩散的能垒，这导致催化剂不可避免的烧结和质量比活性大大降低。在此，我们开发了一种通过 Pt 辅助 H 2还原 Cu 2+生成 Pt@Cu 核/壳纳米粒子 (Pt@Cu NPs) 来合成 PtCu 有序金属间化合物催化剂的新策略。随后在 500–1000 °C 下退火。与常用的湿法浸渍方法相比，核/壳结构在较低的退火温度（500°C）下开始形成有序的 PtCu 合金。Pt@Cu核/壳结构避免了在湿浸渍法高温退火过程中发生的Cu原子跨碳载体扩散到Pt NPs的必要过程，确保了在退火时形成具有更高有序度的PtCu NPs相同的温度。与湿法浸渍法制备的催化剂相比，核/壳策略制备的高度有序的小尺寸PtCu催化剂表现出更高的质量活性和比活性。此外，确定了 ORR 活性与金属间化合物 PtCu NPs 的有序度之间的正相关，
更新日期：2022-09-12
中文翻译：
由 Pt@Cu 核/壳结构制成的用于氧还原反应的有序金属间化合物 PtCu 催化剂
铂基有序金属间化合物是用于高性能燃料电池的氧还原反应 (ORR) 的有前途的低 Pt 催化剂。然而，有序金属间化合物催化剂的合成通常需要高温退火来克服原子扩散的能垒，这导致催化剂不可避免的烧结和质量比活性大大降低。在此，我们开发了一种通过 Pt 辅助 H 2还原 Cu 2+生成 Pt@Cu 核/壳纳米粒子 (Pt@Cu NPs) 来合成 PtCu 有序金属间化合物催化剂的新策略。随后在 500–1000 °C 下退火。与常用的湿法浸渍方法相比，核/壳结构在较低的退火温度（500°C）下开始形成有序的 PtCu 合金。Pt@Cu核/壳结构避免了在湿浸渍法高温退火过程中发生的Cu原子跨碳载体扩散到Pt NPs的必要过程，确保了在退火时形成具有更高有序度的PtCu NPs相同的温度。与湿法浸渍法制备的催化剂相比，核/壳策略制备的高度有序的小尺寸PtCu催化剂表现出更高的质量活性和比活性。此外，确定了 ORR 活性与金属间化合物 PtCu NPs 的有序度之间的正相关，
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