CAS: Ambient Electrochemical Activation of Light Alkanes with Early Transition Metal-Oxo Species

北美丰富但地理分布广泛的天然气和石油资源极大地改变了美国的能源组合。天然气转化为有用的产品依赖于集中地点的高温和高压过程。将天然气从偏远地区输送到这些中心地区往往并不划算。因此，在回收石油的同时，天然气通常会通过在油井中燃烧来丢弃。天然气，主要是甲烷，及其燃烧的产物二氧化碳，都是强有力的温室气体。在这些井场开发将天然气转化为经济上可运输的液体的催化过程是非常可取的。在这个项目中，加州大学洛杉矶分校的刘冲教授正在开发一种新的方法，利用电力将包括甲烷在内的轻烷烃转化为液体产品。刘博士正在研究新的电化学催化剂，并研究这些反应的基本机制。刘博士积极参与外展和教育活动，促进学生对科学、技术、工程和数学(STEM)学科的参与。这些活动包括向洛杉矶地区的当地园丁和农民介绍化学主题，以及在机器学习的帮助下为普通化学课程提供本科建议。在化学系化学催化项目的资助下，加州大学洛杉矶分校的刘博士正在发展对早期过渡金属-氧物种如何在催化过程中破坏甲烷中的碳氢键的机械理解。各种电化学技术结合原位表征(包括X射线吸收光谱)被用来鉴定重要的瞬时中间物种，并在第一性原理计算的辅助下确定反应动力学。此外，还在探索其他分子和材料催化剂，用于常温下低碳烷烃的电化学转化。刘博士采集土壤样本，并为当地园丁和农民分析土壤成分，帮助当地社区发展可持续农业和园艺实践。刘博士还在开发一个基于机器学习的平台，以开发普通化学课程的教学策略，为学生提供课程招生建议，并从长远来看，建立一个在线职业发展建议计划。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

The abundant, yet widely geographically distributed, natural gas and oil resources in North America have dramatically changed the United States energy portfolio. Conversion of natural gas to useful products relies on high temperature and high pressure processes at centralized locations. Transportation of natural gas from remote sources to these central locations is often not economical. As a result, natural gas is often discarded by flaring at the well, while the oil is recovered. Natural gas, which is mostly methane, and its flaring product, carbon dioxide, are both potent greenhouse gases. Development of catalytic processes that convert natural gas into economically-transportable liquids at these well sites is very desirable. In this project, Professor Chong Liu of the University of California, Los Angeles is developing a new approach using electricity to convert light alkanes, including methane, into liquid products. Dr. Liu is studying new electrochemical catalysts and investigating the fundamental mechanisms of these reactions. Dr. Liu is actively engaged in outreach and education activities to promote engagement of students in science, technology, engineering and mathematics (STEM) disciplines. These activities include the introduction of chemistry topics to local gardeners and farmers in the Los Angeles area as well as undergraduate advising for general chemistry courses assisted by machine learning.With the funding from the Chemical Catalysis Program of the Division of Chemistry, Dr. Liu of the University of California, Los Angeles is developing a mechanistic understanding of how early transition metal-oxo species break the carbon-hydrogen bond in methane during the catalysis. A variety of electrochemical techniques in conjunction with in situ characterizations (including X-ray absorption spectroscopy) are employed to identify important transient intermediate species and determine reaction kinetics with the assistance of first-principle calculations. Also under investigation is the exploration of other molecular and materials catalysts for electrochemical conversion of light alkanes under ambient conditions. Dr. Liu takes soil samples and analyzes their composition for local gardeners and farmers, assisting the local community to develop sustainable agriculture and gardening practices. Dr. Liu is also developing a machine-learning-based platform to develop teaching strategies in general chemistry courses, to advise students on course enrollment, and, in the long run, to establish an online advising program for career development.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.