Zhang Wengang, Starr Francis W, Beers Kathryn L, Douglas Jack F
Materials Science and Engineering Division, Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States.
Department of Physics, Wesleyan University, Middletown, Connecticut 06459, United States.
J Phys Chem A. 2022 May 26;126(20):3167-3173. doi: 10.1021/acs.jpca.2c01167. Epub 2022 May 9.
While plastic materials offer many benefits to society, the slow degradation and difficulty in recycling plastics raise important environmental and sustainability concerns. Traditional recycling efforts often lead to materials with inferior properties and correspondingly lower value, making them uneconomical to recycle. Recent efforts have shown promising chemical pathways for converting plastic materials into a wide range of value-added products, feedstocks or monomers. This is commonly referred to as "chemical recycling". Here, we use reactive molecular dynamics (MD) simulations to study the catalytic process of depolymerization of polyethylene (PE) using platinum (Pt) nanoparticles (NPs) in comparison to PE pyrolysis (thermal degradation). We apply a simple kinetic model to our MD results for the catalytic reaction rate as a function of temperature, from which we obtain the activation energy of the reaction, which shows the that the Pt NPs reduce the barrier for depolymerization. We further evaluate the molecular mass distribution of the reaction products to gain insight into the influence of the Pt NPs on reaction selectivity. Our results demonstrate the potential for the reactive MD method to help the design of recycling approaches for polymer materials.
虽然塑料材料给社会带来了诸多益处，但塑料降解缓慢且回收困难引发了重要的环境和可持续性问题。传统的回收努力往往会导致材料性能变差且价值相应降低，使其回收不经济。最近的研究表明，有一些很有前景的化学途径可将塑料材料转化为多种增值产品、原料或单体。这通常被称为“化学回收”。在此，我们使用反应分子动力学（MD）模拟来研究与聚乙烯（PE）热解（热降解）相比，使用铂（Pt）纳米颗粒（NP）催化聚乙烯解聚的过程。我们将一个简单的动力学模型应用于MD模拟结果，以得到催化反应速率随温度的变化关系，从中我们获得了反应的活化能，结果表明Pt纳米颗粒降低了解聚的势垒。我们进一步评估反应产物的分子量分布，以深入了解Pt纳米颗粒对反应选择性的影响。我们的结果证明了反应性MD方法有助于设计聚合物材料回收方法的潜力。
