Nanoporous high-entropy alloys for highly stable and efficient catalysts
Nanoporous high-entropy alloys for highly stable and efficient catalysts
复制标题
用于高度稳定和高效催化的纳米孔高熵合金
DOI：
10.1039/c9ta00505f
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发表时间：
2019-03-21
影响因子：
11.9
通讯作者：
Sun, Shuhui
中科院分区：
文献类型：
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作者：
Qiu, Hua-Jun;Fang, Gang;Sun, Shuhui
可控地将多种不相容的金属元素结合到一个单一的纳米结构中具有不可估量的技术和科学潜力，但对于传统的自下而上的合成方法来说，这仍然是一个挑战。在这里，我们提出了一种通用的、可扩展的方法来制备多组分纳米结构合金，称为纳米孔道高熵合金(NP-HEAs)，该方法结合了本体熔化、快速冷却和去合金化。为了证明这一概念，我们合成了高级AlNiCuPtPdAu，八元AlNiCuPtPdAuCoFe，以及高级全非贵金属AlNiCuMoCoFeNP-HEA，其韧带尺寸约为2-3 nm，并通过脱合金化精确控制组成。AlNiCuPtPdAu NP-HEA具有自然形成的尖晶石-γ-Al_2O_3薄层氧化层，具有极大的高温稳定性(高达600℃)和CO氧化活性。有趣的是，随着表面氧化层的去除，NP-HEA仍然表现出良好的抗200℃10h粗化的能力，这是因为其固有的低扩散率源于多主元素混合效应。在电催化方面，铂负载量较低的NP-HEA对氧还原反应的催化活性是铂/碳的10倍，100K循环后仍保持92.5%的初始活性。
Controllably incorporating multiple immiscible metal elements into one single nanostructure has immeasurable technological and scientific potential, but it remains a challenge for the conventional bottom-up synthetic methods. Herein, we presented a general and scalable route to prepare multi-component nanostructured alloys referred to as nanoporous high-entropy alloys (np-HEAs) by combining bulk melting, fast cooling, and dealloying. To demonstrate this concept, we synthesized senary AlNiCuPtPdAu, octonary AlNiCuPtPdAuCoFe, and senary all-non-noble metal AlNiCuMoCoFe np-HEA with ligament sizes of approximate to 2-3 nm and precisely controlled composition by dealloying the designed precursor alloys. With a naturally formed thin oxide layer of spinel gamma-Al2O3, AlNiCuPtPdAu np-HEA exhibited greatly enhanced high-temperature stability (up to 600 degrees C) and CO oxidation activity. Interestingly, with the removal of the surface oxide layer, np-HEA still showed good resistance to coarsening at 200 degrees C for 10 h due to its intrinsically low diffusivity originating from the multiple-principal-element mixing effect. For electrocatalysis, np-HEA with a low Pt loading amount exhibited 10 times the mass activity of Pt/C for oxygen reduction reaction and maintained 92.5% of its initial activity after 100k electrochemical cycles.