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，但全球变暖的加速已经产生了减少温室气体排放的迫切需要。在美国，天然气燃烧已成为第一大发电来源。然而，与天然气燃烧有关的二氧化碳（CO2），加上开采和运输过程中的甲烷排放，仍然导致温室气体排放超过能源可持续性所需的水平。两种技术--天然气制油（GTL）和催化甲烷热解（CMP）--有望为燃料和化学品制造生产氢气，同时减少温室气体排放。然而，由于碳沉积和金属烧结导致的催化剂失活仍然是甲烷稳定化反应中的主要挑战。以前的研究还没有充分深入地探索基于工艺的催化剂失活和再生机制，以设计节能、有效的再生策略。为此，该项目将直接解决原型载体镍催化剂再生方面的基本知识差距，以实现延长甲烷催化剂寿命的新选择，从而在向可持续燃料和化学品过渡期间促进更好的碳管理和进一步减少温室气体排放。虽然废甲烷转化金属催化剂的再生已经被描述为现象学的，碳气化和金属再分散的全面的基本理解一直缺乏。这部分是由于多相催化中的传统研究方法主要集中在催化反应动力学和吸附在催化剂表面上的分子的动力学，而不是固体催化剂的结构动力学。该项目将联合收割机最先进的原位环境透射电子显微镜（ETEM）与称为计算机视觉的机器学习分支相结合，以直接监测再生条件下的积碳和Ni催化剂结构变化。废金属催化剂再生的基本理解的进步将通过三个目标来实现：1）建立再生性能和结构演变的高通量相关性的操作方法学，2）确定优化气化条件的碳气化机制和动力学，以及3）确定金属再分散机制和支持循环反应-再生过程的效果。这三个目标的成功整合将在除碳、气化诱导烧结和Ni再分散序列期间建立气化动力学和催化剂状态之间的直接相关性。这些相关性将使再生条件参数的合理调整，以实现完全除碳和有效的镍催化剂再分散。这些对再生废镍催化剂的基本见解可以为其他负载型金属催化剂系统带来新的实用再生策略。除了该项目的技术方面，研究人员将建立一个跨学科，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融入教育的活动，激发和激励学生和K-12教师关于STEM领域的互动研讨会，该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的智力价值和更广泛的影响审查进行评估来支持的搜索.

项目成果

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.

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