Electrochemical conversion of nitrogen to ammonia-experimental and theoretical studies

氮电化学转化为氨——实验和理论研究

• 批准号: EP/N510038/1
• 负责人: Sebastian Metz
• 金额: $ 3.03万
• 依托单位: Science and Technology Facilities Council
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2016
• 资助国家: 英国
• 起止时间: 2016 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FN510038%2F1
• 关键词: Electrochemical; conversion; nitrogen; ammonia; experimental

This University of Oxford led project will demonstrate the feasibility of producing ammonia, an energy vector with multiple applications, in a carbon free synthesis powered by renewable energy. This part of the study aims to simulate the electrochemical syntheses of ammonia from nitrogen and hydrogen/water.Bulk models to represent the experimental systems in a realistic fashion At the first stage, we will focus on electrode materials with varying amounts of Samarium, namely Sm2-xSrxNiO4 (with x=0.4, 0.5, 0.8 and 1.2) and SmFe0.7Cu0.3- xNixO3 (with x=0, 0.1, 0.2 and 0.3), that have been reported in the literature. These systems have been characterized experimentally and shown a strong difference in catalytic activity towards electrochemical synthesis of ammonia. Aim of the computational simulations is to understand the difference in activity in order to help decision making on potential improved experimental systems and/or predict trends in catalytic activity.To succeed in this ambitions, a broad skill set of computational modelling techniques is required. As this might become a re-appearing pattern for newly identified materials or potential catalysts, we'll establish a protocol that can be followed for any new material of interest for the electrodes This will form the basis for the work undertaken in the first part of the project.- Generation of starting structure of bulk material based on available experimental evidence- Monte Carlo (MC) simulations (using the in-house code DL_MONTE ) to the thermodynamically stable phase- Validation of the model by theoretical reproduction of bulk properties, e.g. the ionic conductivity with Adaptive Kinetic Monte Carlo (AKMC) techniques (using the in-house code DL_AKMC )Establishing a bulk structure is key for validation of most experimental values. The reactivity of the electrode, however, depends on the catalytically active surface. In the secnd part of the project, we'll therefore establishe a reliable and reproducible protocol to generate different crystal surfaces and determine the likelihood of their appearance in the experimental systems (using the in-house code DL_POLY , and/or CRYSTAL)To keep the computational efficiency as low as possible, we'll establish realistic, but still efficient representations of the systems of interest by using a cutting cluster approach.In the third part of the study, we'll use these representations to study the reactivity at the interface, taking into account different competing reactions:We'll simulate the catalytic conversion of nitrogen to ammonia, which is the reaction we are actually interested in. In addition, we'll investigate potential competing reaction like the generation of hydrogen at the cathode (2H+ + 2e- -> H2), reducing the Faradaic efficiency of the MEAs. Namely, we will evaluate the influence of the electrolyte, and/or electromagnetic fields on the reaction energies, but also on the geometries (an effect that is normally neglected).At the end of the project, we aim to be able to use computational simulations to understand and to be anle to make predictions on the difference in activity in a diverse group of materials in order to help decision making on potential improved experimental systems and/or predict trends in catalytic activity.

该牛津大学LED项目将证明在由可再生能源提供支持的无碳合成中生产氨（具有多种应用的能量载体）的可行性。该研究的这一部分旨在模拟氮和氢/水的氨的电化学合成。BULK模型在第一阶段以现实的方式代表实验系统，我们将专注于具有不同量的samarium的电极材料，即SM2-XSRXNIO4（即x = 0.4，0.4，0.8，0.8和1.2）和1.2）和1.2）和1.2）和1.2）和1.2）和1.2）和1.2）和1.2）。 Xnixo3（具有X = 0、0.1、0.2和0.3），在文献中已报道。这些系统已通过实验表征，并显示出催化活性对氨的催化活性有很大的差异。计算模拟的目的是了解活动的差异，以帮助对潜在的改进的实验系统和/或预测催化活动的趋势做出决策。要在这种野心中取得成功，需要广泛的计算建模技术技能。 As this might become a re-appearing pattern for newly identified materials or potential catalysts, we'll establish a protocol that can be followed for any new material of interest for the electrodes This will form the basis for the work undertaken in the first part of the project.- Generation of starting structure of bulk material based on available experimental evidence- Monte Carlo (MC) simulations (using the in-house code DL_MONTE ) to the thermodynamically stable phase- Validation of the model by theoretical散装特性的繁殖，例如具有自适应动力学蒙特卡洛（AKMC）技术（使用内部代码DL_AKMC）的离子电导率是验证大多数实验值的关键。但是，电极的反应性取决于催化活性表面。 In the secnd part of the project, we'll therefore establishe a reliable and reproducible protocol to generate different crystal surfaces and determine the likelihood of their appearance in the experimental systems (using the in-house code DL_POLY , and/or CRYSTAL)To keep the computational efficiency as low as possible, we'll establish realistic, but still efficient representations of the systems of interest by using a cutting cluster approach.In the third part of the study, we'll use these representations to study the考虑到不同的竞争反应，在界面处的反应性：我们将模拟氮对氨的催化转化，这是我们实际感兴趣的反应。此外，我们将研究潜在的竞争反应，例如在阴极（2H + + 2e- + 2e--> h2）中产生氢，从而降低了该量度的FARADAIC效率。即，我们将评估电解质和/或电磁场对反应能量的影响，但也对几何形状（通常被忽略的效果）。在项目结束时，我们旨在使用计算模拟来使用计算模拟，以理解并在依赖阶段的依赖范围内进行策略的依赖和促进的效果，以实现良好的效果，以实现各种依赖的效果，并在依赖界限中进行依据，以实现各种依赖的影响，并在阶段中进行依赖的效果，以实现各种依据，以实现各种依据，以促进材料的各种依据。 活动。

项目成果

A combined experimental/theoretical approach to accelerated fuel cell development by quantitative prediction of redox potentials

• DOI: 10.1016/j.jpowsour.2018.07.056
• 发表时间: 2018-09
• 期刊: Journal of Power Sources
• 影响因子: 9.2
• 作者: K. Sen;A. Creeth;Sebastian Metz