Role of Kinetics and Thermodynamics in Controlling the Crystal Structure of Nickel Nanoparticles Formed on Reduced Graphene Oxide: Implications for Energy Storage and Conversion Applications
Role of Kinetics and Thermodynamics in Controlling the Crystal Structure of Nickel Nanoparticles Formed on Reduced Graphene Oxide: Implications for Energy Storage and Conversion Applications
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DOI：
10.1021/acsanm.2c05528
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发表时间：
2023-06
影响因子：
5.9
通讯作者：
Mahmound Tamadoni Saray;Vitaliy Yurkiv;R. Shahbazian‐Yassar
中科院分区：
文献类型：
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作者：
Mahmound Tamadoni Saray;Vitaliy Yurkiv;R. Shahbazian‐Yassar
超快加热是近年来出现的一种加速纳米粒子合成过程并控制其形貌的方法。然而，目前尚不清楚加热速率如何影响金属纳米颗粒的形成，特别是那些在基材上形成的金属纳米颗粒。在这里，我们探索了在缓慢（20 °C/min）和超快（103°C/s）加热速率下在氧化石墨烯（GO）衬底上形成镍（Ni）纳米颗粒。使用像差校正的透射电子显微镜在加热微芯片装置上原位进行实验。有趣的是，当采用超快加热时，GO结构在控制纳米颗粒的稳定性方面是最有效的，导致六方密堆积的Ni相（hcp-Ni），因为与石墨基底的晶格失配较少。相反，fcc-Ni纳米颗粒在缓慢加热过程下形成，其中没有观察到与GO晶体结构的强相关性。此外，超快加热导致更小尺寸的纳米颗粒，这可以归因于快速还原，成核速率，和更高的扩散势垒的hcp-Ni晶体上的rGO。然而，镍纳米颗粒的晶体结构的稳定性仍然不受其尺寸的影响。这些结果表明，在材料的非平衡加工过程中，基板对晶体结构的关键作用，以及热力学与动力学在创造用于能量存储和转换应用的材料的新相方面的竞争效应。
Ultrafast heating has emerged recently to speed up the synthesis processes of nanoparticles and control their morphology. However, it is not clear how the heating rate affects the formation of metal nanoparticles, particularly those formed on substrates. Here, we explored the formation of nickel (Ni) nanoparticles on graphene oxide (GO) substrates under slow (20 °C/min) and ultrafast (103°C/s) heating rates. The experiments were performed in situ on heating microchip devices using an aberration-corrected transmission electron microscope. Interestingly, the GO structure was the most effective in controlling the stability of nanoparticles when ultrafast heating was employed, leading to a hexagonally close-packed Ni phase (hcp-Ni) because of less lattice mismatch with the graphitic substrate. On the contrary,fcc-Ni nanoparticles formed under a slow heating process where no strong correlation with the GO crystal structure was observed. Additionally, ultrafast heating resulted in smaller-size nanoparticles which could be ascribed to rapid reduction, nucleation rate, and higher diffusion barrier ofhcp-Ni crystals on rGO. Nevertheless, the stability of the crystal structure of the nickel nanoparticles remains unaffected by their size. These results indicate the crucial role of the substrate on crystal structure during the nonequilibrium processing of materials and the competing effects of thermodynamics versus kinetics in creating novel phases of materials for energy storage and conversion applications.