<br>原位 TEM 观察双金属 Pt-Ni 纳米粒子在高温下的结构和化学演化：对多相催化的影响,ACS Applied Nano Materials

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原位 TEM 观察双金属 Pt-Ni 纳米粒子在高温下的结构和化学演化：对多相催化的影响
ACS Applied Nano Materials ( IF 5.3 ) Pub Date : 2024-07-03 , DOI: 10.1021/acsanm.4c02753
Xiner Lu ₁ , Sooyeon Hwang ₂ , Kai He ₁

Affiliation

铂基双金属纳米颗粒（NP）因其在催化领域的应用而引起人们极大的兴趣。这些纳米粒子的催化性能很大程度上取决于它们的形态、结构和成分，其对热输入的响应仍然难以充分理解。本研究利用原位透射电子显微镜研究了单晶 Pt-Ni 纳米颗粒的热诱导结构和化学演化。观察到的形态演化包括从截角八面体到类球形各向同性形状的小面发展，随后由于表面原子迁移和颗粒-基底相互作用所导致的界面润湿而在高温下形成薄煎饼状椭圆体形状。原位扫描透射电子显微镜与能量色散 X 射线光谱图的比较研究表明，固溶体的组成构型可以在很大的温度范围内保留，而核壳纳米粒子通过化学均质化在温度升高。这些发现阐明了热输入对 Pt-Ni 双金属纳米粒子的结构演变和成分重新分布的影响，为多相催化剂的设计提供了宝贵的见解。

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In Situ TEM for Structural and Chemical Evolutions of Bimetallic Pt–Ni Nanoparticles at Elevated Temperatures: Implications for Heterogeneous Catalysis

Platinum-based bimetallic nanoparticles (NPs) are of great interest for their applications in catalysis. The catalytic properties of these NPs are significantly dependent on their morphology, structure, and composition, whose response to thermal input remains challenging to be fully understood. This study investigates the thermally induced structural and chemical evolutions of single-crystalline Pt–Ni NPs using in situ transmission electron microscopy. The observed morphological evolution includes the facet development from a truncated octahedron to a spherical-like isotropic shape, followed by the formation of a pancake-like ellipsoid shape at high temperatures due to surface atom migration and interfacial wetting enabled by the particle–substrate interaction. Comparative investigations by in situ scanning transmission electron microscopy with energy-dispersive X-ray spectroscopy mapping elucidate that the solid-solution compositional configuration can be retained over a large temperature range, while core–shell NPs undergo irreversible solid-solution transitions through chemical homogenization at elevated temperatures. These findings elucidate the effect of thermal input on the structural evolution and compositional redistribution of Pt–Ni bimetallic NPs, offering valuable insights into the design of heterogeneous catalysts.

更新日期：2024-07-03

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