Goldie Stuart J, Coleman Karl S
Department of Chemistry, Durham University, South Road, DurhamDH1 3LE, U.K.
Department of Chemistry, School of Physical Sciences, University of Liverpool, Peach Street, LiverpoolL69 7ZE, U.K.
ACS Omega. 2023 Jan 12;8(3):3278-3285. doi: 10.1021/acsomega.2c06848. eCollection 2023 Jan 24.
Graphitization of carbon offers a promising route to upcycle waste biomass and plastics into functional carbon nanomaterials for a range of applications including energy storage devices. One challenge to the more widespread utilization of this technology is controlling the carbon nanostructures formed. In this work, we undertake a meta-analysis of graphitization catalyzed by transition metals, examining the available electron microscopy data of carbon nanostructures and finding a correlation between different nanostructures and metal particle size. By considering a thermodynamic description of the graphitization process on transition-metal nanoparticles, we show an energy barrier exists that distinguishes between different growth mechanisms. Particles smaller than ∼25 nm in radius remain trapped within closed carbon structures, while nanoparticles larger than this become mobile and produce nanotubes and ribbons. These predictions agree closely with experimentally observed trends and should provide a framework to better understand and tailor graphitization of waste materials into functional carbon nanostructures.
碳的石墨化提供了一条将废弃生物质和塑料升级转化为功能性碳纳米材料的有前景的途径，这些材料可用于包括储能装置在内的一系列应用。该技术更广泛应用面临的一个挑战是控制所形成的碳纳米结构。在这项工作中，我们对过渡金属催化的石墨化进行了荟萃分析，研究了碳纳米结构的现有电子显微镜数据，并发现了不同纳米结构与金属颗粒尺寸之间的相关性。通过考虑过渡金属纳米颗粒上石墨化过程的热力学描述，我们表明存在一个能垒，它区分了不同的生长机制。半径小于约25 nm的颗粒被困在封闭的碳结构中，而大于此尺寸的纳米颗粒变得可移动并产生纳米管和碳带。这些预测与实验观察到的趋势密切相符，应该能提供一个框架，以更好地理解并将废弃材料的石墨化定制为功能性碳纳米结构。
