Molecular Characterization of Water Oxidation in Metal-Organic Frameworks through Computer Simulations

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Molecular Characterization of Water Oxidation in Metal-Organic Frameworks through Computer SimulationsComputer simulations have become a powerful tool to gain critical insights into complex molecular processes, which are otherwise difficult to obtain by other means. However, achieving the necessary accuracy for realistic and predictive simulations is a challenge. In this project, Dr. Paesani and his group are developing and applying a novel and powerful simulation methodology to model water oxidation in a class of highly porous solids known as metal-organic frameworks (MOFs). Water oxidation is one of the key reactions in natural photosynthesis. Therefore, understanding the steps involved in water oxidation at the molecular level may aid in the development of artificial photosynthetic systems. MOFs are a relatively new class of materials and are ideal for these catalysts. The studies carried out by Dr. Paesani and his group are advancing both the theory and the computer modeling of MOFs and their chemistry, which are key to the rational development of new catalysts. In parallel with the research activities, an innovative education and outreach plan is being established to introduce freshman and sophomore undergraduate students to computational methods in chemistry and materials research. Dr. Paesani and his group are also promoting interest in STEM disciplines among underprivileged and underrepresented minority students through the development of summer exchange programs at the University of California - San Diego.The fundamental understanding of how to control water oxidation to molecular oxygen is a prerequisite for the development of artificial systems to harvest and convert solar energy as well as to enable visible-light-driven organic synthesis. It is well known that the availability of water as an electron donor opens up a wide variety of reductive processes that can be driven with electricity or sunlight. Since water is one of the ultimate products of fossil fuel combustion, the conversion of H2O molecules back into fuel involves thermodynamically uphill reactions that remove oxygen atoms. In this project, Dr. Paesani and his group are performing fundamental studies to investigate the elementary steps involved in water oxidation reactions in metal-organic frameworks (MOFs). MOFs are a relatively new class of porous materials with large surface areas that have already found application in gas storage (e.g., methane and hydrogen storage), carbon capture, hydrocarbon separation, chemical sensing, nonlinear optics, biomedical imaging, drug delivery, catalysis, electrical and proton conductivity, magnetism, and luminescence. Since MOF structure and physicochemical properties are highly tunable, MOFs represent promising platforms for building efficient functional devices for solar energy harvesting and conversion. Dr. Paesani and his group are developing and applying novel simulation methodologies that combine many-body representations of the molecular interactions with advanced techniques to describe chemical reactivity in the condensed phase to characterize the elementary steps associated with catalytic processes in MOFs. This information is key to the rational design of new MOF structures with properties specifically tailored for solar energy harvesting and conversion. The interdisciplinary nature of the research project represents an extraordinary opportunity for training at the interface of different disciplines, providing bridges and inter-connections between the fundamental laws of physics and the molecular properties of materials at the nanoscale. In this context, mentoring and outreach activities are specifically designed to promote science disciplines among high school and college students from underprivileged and underrepresented minorities through the development and implementation of summer exchange programs at UC San Diego.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.