Collaborative Research: Controlling Metal-Oxide Interface Chemistry for New C-H Activation Catalysts

在清洁能源向可再生和可持续的净零碳燃料和化学品过渡期间，世界将继续依赖碳氢资源。因此，有很大的机会通过高效的化学加工来生产易于运输的液体燃料和化学品，从而减少我国巨大的天然气储量的碳足迹。该项目解决了天然气化学加工中的一个关键挑战--根据需要打破碳-氢键，以制造更高价值的燃料和化学品。催化技术是天然气节能升级的关键。为此，该项目研究了一种新型碳氢化合物转化催化剂，这种催化剂有可能使天然气在现场转化为液体燃料和化学品，从而极大地提高能源效率并显著减少温室气体排放。该项目还将投资于针对经济困难本科生的研究体验，这些本科生中女性和代表性不足的少数民族比例不成比例。本科生将参与同伴指导网络，这在促进本科生成功方面特别有效，特别是当团队中的学生具有不同的文化和社会经济背景时。该项目将结合研究人员的实验和计算专业知识，基于Au/氧化物界面的独特性质开发新的异解型C-H活化催化剂，该催化剂将通过改变氧化物的组成来调整以最大限度地提高活性。采用密度泛函理论和新的原位红外光谱技术相结合的方法，对经过精心选择的一系列Au/MOX催化剂上的H2活化参数进行了量化。H-H键和C-H键的活化是密切相关的过程，因此广泛的方法是首先研究氧化物组成如何调节H2活化的热力学和动力学，然后扩展这一知识来设计有效的C-H活化界面。机器学习技术将利用这些结果来调查数千种氧化物成分的氢活化化学，这将提供对控制金属-氧化物界面复杂相互作用的潜在物理化学过程的直接洞察。结合有意设计的实验来告知和改进计算模型，这项研究将超越识别影响C-H活化的因素(如支撑体的可还原性、支撑体的碱性、M-OH键的灵活性)，以评估每个系统变量的相对影响。由此产生的C-H键活化化学将用一套根据其吸附性能选择的碳氢化合物和催化苯甲醇氧化进行测试。理想情况下，该项目将产生一种研究协议，将有效的计算筛选和金属载体催化剂组合的实验验证相结合，该组合是为在广泛的碳氢和有机分子中有效地激活C-H键而量身定做的。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 world will continue to rely on hydrocarbon resources during the Clean Energy Transition to renewable and sustainable net-zero carbon fuels and chemicals. Thus, there is a substantial opportunity to reduce the carbon footprint of our Nation’s tremendous natural gas reserves through efficient chemical processing to manufacture readily transportable liquid fuels and chemicals. The project addresses a key challenge in natural gas chemical processing – breaking the carbon-hydrogen bonds as needed to manufacture higher-value fuels and chemicals. Catalytic technology is critical to energy efficient natural gas upgrading. To that end, the project investigates a new class of hydrocarbon conversion catalysts that can potentially enable natural gas to be converted to liquid fuels and chemicals in the field, thereby generating enormous boosts in energy efficiency and a significant reduction in greenhouse gas emissions. The project also will invest in research experiences targeted to economically disadvantaged undergraduate students, who are disproportionately women and under-represented minorities. The undergraduates will be engaged in a peer-mentoring network, which can be particularly effective in promoting undergraduate success, especially when the students in the team have diverse cultural and socio-economic backgrounds. The project will combine the investigators’ experimental and computational expertise to develop new heterolytic C-H activation catalysts based on the unique properties of Au/oxide interfaces, which will be tuned to maximize activity by varying the composition of the oxide. A combination of density functional theory and new in-situ IR techniques will be employed to quantify H2 activation parameters over a carefully chosen series of Au/MOx catalysts. H-H and C-H bond activation are closely related processes, so the broad approach is to first study how oxide composition tunes the thermodynamics and kinetics of H2 activation, and then extend this knowledge to design effective interfaces for C-H activation. Machine learning techniques will use these results to survey H2 activation chemistry for thousands of oxide compositions, which will provide direct insight into underlying physio-chemical processes that govern complex interactions at the metal-oxide interface. Coupled with experiments intentionally designed to inform and refine the computational models, the research will go beyond identification of factors that impact C-H activation (such as support reducibility, support basicity, M-OH bond flexibility) to assess the relative impact of each system variable. The resulting C-H bond activation chemistry will be tested with a suite of hydrocarbons chosen for their adsorption properties and with catalytic benzyl alcohol oxidation. Ideally, the project will generate a research protocol that will combine efficient computational screening and experimental validation of metal-support catalyst combinations tailored for efficient C-H bond activation across a broad range of hydrocarbon and organic molecules.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.