SusChEM: Investigation of a Core-Shell Redox Catalyst Platform for Oxidative Dehydrogenation of Ethane

SusChEM：乙烷氧化脱氢核壳氧化还原催化剂平台的研究

• 批准号: 1604605
• 负责人: Fanxing Li
• 金额: $ 44.99万
• 依托单位: North Carolina State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-08-01 至 2021-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1604605&HistoricalAwards=false
• 关键词: SusChEM; Investigation; Core; Shell; Redox

The project will investigate the oxidative dehydrogenation (ODH) of ethane to produce ethylene - a high volume chemical intermediate. A novel approach is employed that utilizes a core-shell catalyst design in combination with a chemical looping redox cycle to achieve ODH without direct feed of oxygen. The combined approach potentially eliminates a costly and energy-intensive process for separating oxygen from air, while also reducing carbon emissions. The work will provide multi-disciplinary educational opportunities for graduate and undergraduate students, as well as outreach activities to high school students and teachers for stimulating interest in STEM careers.The core-shell redox catalyst is both an active catalyst and an effective lattice oxygen ion donor for ethane ODH in a chemical-looping scheme. The work plan tests three key hypotheses: 1) Chemically and structurally compatible primary (cobalt/iron) oxides and perovskites can be assembled into a stable core-shell arrangement for ethane ODH under a cyclic redox mode; 2) The surface properties of the core-shell redox catalyst can be tailored by tuning the metal cation oxidation state and defect structure of the mixed ionic-electronic conductor (MIEC) shell, rendering a highly effective catalyst for ethane ODH in the absence of gaseous oxidants; 3) Ethane ODH reaction occurs primarily on the perovskite surface via homolytic C-H bond cleavage through a modified Mars-van Krevelen mechanism. To test these hypotheses, phase-compatible core and shell materials will be identified and then assembled into core-shell particles. The effects of perovskite A-site and B-site substitutions on ODH activity and selectivity will be investigated and correlated to the defect structure and cation oxidation state of the shell material. Kinetic and mechanistic aspects will be investigated over pellets and thin films replicating the core-shell and shell structures using in-situ Raman and FT-IR/DRIFTS, a molecular beam reactor coupled with an X-ray photoelectron spectrometer, and pulse isotope studies. The studies will potentially result in fundamentally new materials and schemes that can significantly improve the efficiency for ethylene production from natural gas while reducing emissions.

该项目将研究乙烷的氧化脱氢（ODH），以产生乙烯 - 高体积化学中间体。 采用了一种新颖的方法，该方法将使用核心壳催化剂设计与化学环的氧化还原循环结合使用，以实现ODH而无需直接进食氧气。 合并的方法有可能消除将氧气与空气分离的昂贵和能源密集型过程，同时还可以减少碳排放。 这项工作将为研究生和本科生提供多学科的教育机会，并向高中生和老师提供宣传活动，以刺激对STEM职业的兴趣。核心壳氧化还原催化剂既是活跃的催化剂，又是有效的晶状体氧气供体，用于化学方案中的乙烷ODH。 工作计划检验了三个关键假设：1）在环状氧化还原模式下，可以将化学和结构兼容的原代（钴/铁）氧化物和钙钛矿组装成乙烷ODH的稳定核心壳布置； 2）可以通过调整混合离子电子导体（MIEC）壳的金属阳离子氧化态和缺陷结构来定制核壳氧化还原催化剂的表面特性，从而在没有气态氧化剂的情况下为乙烷ODH提供了高效的乙烷ODH催化剂； 3）乙烷ODH反应主要发生在钙钛矿表面上，通过均利性C-H键通过改良的火星van krevelen机制发生。为了检验这些假设，将确定相位兼容的核心和壳材料，然后组装成核壳颗粒。 钙钛矿A位点和B位置取代对ODH活性和选择性的影响将与壳材料的缺陷结构和阳离子氧化态相关。动力学和机械方面将通过颗粒和薄膜进行研究，并使用原位拉曼和ft-ir/drifts复制核心壳和壳结构，这是一种分子束反应器，与X射线光电子光谱仪和脉冲同位素研究相连。这些研究可能会产生从根本上产生新材料和方案，这些材料和方案可以显着提高天然气的乙烯生产效率，同时减少排放。