Atomistic and Multi-scale Modelling of Functionalized Graphene and Hydrogen Diffusion in Advanced Materials

2016年，世界经济论坛新兴技术元理事会将二维(2D)材料评为全球十大新兴技术之一。像石墨烯这样的2D材料由单层原子片组成，可以用来制造新的材料和设备。它们被提出用于广泛的应用，如传感器技术、复合材料、储能、环境过滤器、药物输送系统和光电子学。石墨烯是一种重要的二维材料，其重要意义得到了2010年诺贝尔物理学奖的认可。石墨烯的应用需要均匀分散在主体材料中，并与其他材料建立强键。采用化学官能化方法改善石墨烯的分散性，形成较强的界面。氧化石墨烯(GO)用于高性价比的功能化石墨烯的批量生产。GO可以从块状石墨中生产出来。它是分散性的，具有羟基和其他官能键，可以促进与材料更好的相互作用。目前，对功能化石墨烯和氧化石墨烯的力学和界面性质的研究非常有限。拟议研究计划的第一部分检查功能化石墨烯和GO的力学和机械性能以及它们的界面，以支持新的材料和器件设计。将使用基于计算机的原子和多尺度建模方法，并将在选定的案例中与实验进行比较。两名博士生、两名硕士研究生和三名本科生将接受这项研究的培训。 拟议研究计划的第二部分旨在对氢在锆酸盐和钛酸铅(PZT)中的扩散有一个基本的了解。锆压力管是核电站的关键部件，而现代喷油器中使用的是PZT执行器。实验研究证实，压力管道中氢化物的形成和由此产生的氢化物驱动的裂化是一个主要的安全问题。实验还证实了PZT的极化损失是由于氢，这是使用基于PZT的注入器在氢技术应用的障碍。氢化物驱动开裂的确切机制还不完全清楚，对PZT与氢的相互作用也知之甚少。提出的计划包括对氢在锆晶格和PZT晶格中的相互作用和扩散进行全面的基于计算机的原子模拟，以及一个多尺度的扩散模型。这些发现将为压力管的安全设计和氢气技术注射器的开发提供支持。两名博士生和两名本科生将接受这项研究的培训。受训者将通过同行评议的出版物、会议和与业界的互动来传播研究成果。该项目将使用WestGrid/Compute Canada的高性能计算设施。

In 2016, the Meta Council of Emerging Technologies of World Economic Forum identified two-dimensional (2D) materials as one of the top ten emerging technologies of the world. 2D materials such as graphene consist of single-layer atom sheets that can be used to build new materials and devices. They are proposed for a wide range of applications, such as sensor technology, composite materials, energy storage, environmental filters, drug delivery systems, and optoelectronics. Graphene is an important 2D material and its significance was recognized by the 2010 Nobel Prize in Physics. Application of graphene requires homogeneous dispersion in host materials and creation of strong bonds with other materials. Chemical functionalization is used to improve dispersion of graphene and form strong interfaces. Graphene-oxide (GO) is used for cost-effective mass production of functionalized graphene. GO can be produced from bulk graphite. It is dispersive and has hydroxyl and other functional bonds that can facilitate better interaction with materials. Currently, very limited research exists on the mechanical and interfacial properties of functionalized graphene and GO. The first part of the proposed research program examines the mechanics and mechanical properties of functionalized graphene and GO and their interfaces to support novel material and device design. A computer-based atomistic and multi-scale modeling approach will be used and comparisons with experiments will be made in selected cases. Two PhD students, two MSc students and three undergraduates will be trained on this research. The second part of the proposed research program aims to obtain a fundamental understanding of diffusion of hydrogen in Zirconium and Lead Zirconate Titanate (PZT). Zirconium pressure tubes are key elements of nuclear power plants, and PZT actuators are used in modern fuel injectors. Experimental studies confirm hydride formation in pressure tubes, and the resulting hydride-driven cracking as a major safety concern. Experiments also confirm the loss of polarization of PZT due to hydrogen, which is a barrier for the use of PZT-based injectors in hydrogen technology applications. The exact mechanism of hydride-driven cracking is not fully understood, and little is known about the interaction of PZT with hydrogen. The proposed program involves comprehensive computer-based atomistic modeling of hydrogen interaction and diffusion in zirconium and PZT lattices and a multi-scale model for diffusion. The findings will support safe design of pressure tubes and development of injectors for hydrogen technology. Two PhD students and two undergraduates will be trained on this research. The trainees will disseminate the research findings through peer-reviewed publications, conferences, and interaction with industry. High-performance computing facilities of WestGrid/Compute Canada will be used in this project.