CAREER: Mechanistic Understanding and Strategies to Improve the Regeneration of Supported Nickel Catalysts for Methane Conversion

职业：提高甲烷转化负载型镍催化剂再生的机理理解和策略

• 批准号: 2238213
• 负责人: Yuanyuan Zhu
• 金额: $ 59.67万
• 依托单位: University of Connecticut
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-06-01 至 2028-05-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2238213&HistoricalAwards=false
• 关键词: CAREER; Mechanistic; Understanding; Strategies; Improve

The acceleration of global warming has produced a pressing need to reduce greenhouse gas emissions despite the ever-increasing demand for energy. In the United States, natural gas combustion has become the No. 1 source of electricity generation. However, the carbon dioxide (CO2) associated with natural gas combustion, combined with methane emissions during its extraction and transport, still contributes to greenhouse gas emissions beyond levels required for energy sustainability. Two technologies - gas-to-liquids (GTL) and catalytic methane pyrolysis (CMP) – hold promise for producing hydrogen for both fuel and chemicals manufacturing while decreasing greenhouse gas emissions. However, catalyst deactivation due to carbon deposition and metal sintering are still major challenges in methane valorization reactions. Previous research studies have not explored process-based catalyst deactivation and regeneration mechanisms in sufficient depth to devise energy-efficient, effective regeneration strategies. To that end, the project will directly address fundamental knowledge gaps in the regeneration of prototypical supported nickel (Ni) catalysts to enable new options for extending methane catalyst lifetime, thus contributing to better carbon management and further reduction of greenhouse gas emissions during the transition to sustainable fuels and chemicals. Although the regeneration of spent methane conversion metal catalysts has been described phenomenologically, a comprehensive fundamental understanding of carbon gasification and metal redispersion has been lacking. This is partly due to conventional investigation methodologies in heterogeneous catalysis that focus mainly on the catalytic reaction kinetics and dynamics of molecules adsorbed on catalyst surfaces, not on the structural dynamics of solid catalysts. The project will combine state-of-the-art, in-situ environmental transmission electron microscopy (ETEM) with a branch of machine learning known as computer vision to directly monitor both carbon deposits and Ni catalyst structural changes under regeneration conditions. Advancement of fundamental understanding of spent metal catalyst regeneration will be achieved through three aims: 1) establish an operando methodology for high-throughput correlation of regeneration performance and structural evolution, 2) determine carbon gasification mechanisms and kinetics for optimized gasification conditions, and 3) determine metal redispersion mechanisms and support effects enabling a cyclic reaction-regeneration process. Successful integration of the three aims will establish direct correlations between the gasification kinetics and state of the catalyst during the carbon removal, gasification-induced sintering, and Ni redispersion sequence. The correlations will enable rational tuning of regeneration condition parameters to achieve complete carbon removal and effective Ni catalyst redispersion. These fundamental insights into rejuvenating spent Ni catalysts can lead to new practical regeneration strategies for other supported metal catalyst systems. Beyond the technical aspects of the project, the investigator will establish an interdisciplinary, practical, and inspiring program “The Amazing Life Cycle of Nanocatalysts.” The program will train a new generation of students in catalysis through activities integrating research into education, interactive workshops that excite and inspire students and K–12 teachers about STEM fields, and outreach efforts attracting and recruiting underrepresented students to engineering.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

尽管对能源的需求不断增加，但全球变暖的加速迫切需要减少温室气体排放。在美国，天然气混合物已成为发电的第一源。但是，与天然气混合物相关的二氧化碳（CO2）在提取和运输过程中与甲烷排放结合，仍然有助于温室气体排放，超出能源可持续性所需的水平。两种技术 - 气液（GTL）和催化甲烷热解（CMP） - 在减少温室气体排放的同时，有望为燃料和化学制造生产氢。然而，由于碳沉积和金属烧结而导致的催化剂停用仍然是甲烷价反应的主要挑战。先前的研究尚未探索基于过程的催化剂停用和再生机制，以设计能节能，有效的再生策略。为此，该项目将直接解决原型支持的镍（NI）催化剂再生中的基本知识差距，以实现新的选择，以延长甲烷催化剂寿命，从而有助于更好地减少碳管理，并在过渡到可持续燃料和化学物质的过渡过程中进一步减少温室气体的排放。尽管在现象学上已经描述了消费甲烷转化金属催化剂的再生，但缺乏对碳气化和金属重新分散的全面理解。这部分是由于异质催化中的常规投资方法主要集中于吸附在催化剂表面上的分子的催化反应动力学和动力学，而不是固体催化剂的结构动力学上。该项目将结合最先进的，原位环境传输电子显微镜（ETEM）和一个被称为计算机视觉的机器学习分支，以直接监测碳沉积物和在再生条件下的NI催化剂结构变化。通过三个目的，将实现对支出金属催化剂再生的基本理解的进步：1）建立一种以高通量相关性和结构进化的高通量相关性的操作方法，2）确定碳气化机制和动力学的优化气化条件，以及3）确定金属重新发射机制和支持促进反应的方法。成功整合这三个目标将在碳去除，气化引起的烧结和Ni重新分散序列之间建立气化动力学和催化剂状态之间的直接相关性。相关性将使再生条件参数的合理调整能够实现完全去除碳和有效的NI催化剂重新分散。这些对复兴消费的NI催化剂的基本见解可以为其他支持的金属催化剂系统提供新的实用再生策略。除了项目的技术方面，研究人员还将建立一个跨学科，实用和鼓舞人心的计划“纳米催化剂的惊人生命周期”。该计划将通过将研究纳入教育，激动和激发学生和K -12老师的互动研讨会的活动来培训新一代学生进行催化培训，并激发了有关STEM领域的教师，以及宣传工作吸引和招募了代表性不足的学生进行工程学。该奖项反映了NSF的法定任务，并通过评估基金会的智力效果，以诚实地支持支持，并诚实地支持了基金会的范围。

项目成果

In-situ ETEM Observation of Competing Mechanisms for Filamentous Carbon Gasification

丝状碳气化竞争机制的原位 ETEM 观察

• DOI: 10.1093/micmic/ozad067.663
• 发表时间: 2023
• 期刊: Microscopy and Microanalysis
• 影响因子: 2.8
• 作者: Nielsen, Monia R;March, Seth;Sainju, Rajat;Zhu, Chunxiang;Gao, Pu-Xian;Suib, Steven L;Zhu, Yuanyuan
• 通讯作者: Zhu, Yuanyuan

Quantitative gas-phase transmission electron microscopy: Where are we now and what comes next?

• DOI: 10.1557/s43577-023-00648-8
• 发表时间: 2024-02-05
• 期刊: MRS BULLETIN
• 影响因子: 5
• 作者: Jinschek，Joerg R.;Helveg，Stig;Crozier，Peter A.
• 通讯作者: Crozier，Peter A.