CAREER: Large-scale quantum-continuum simulation of layered metal oxide semiconductor photoelectrodes under finite-temperature electrochemical conditions

NON-TECHNICAL SUMMARY The Division of Materials Research and the Division of Chemistry provide funding for this CAREER award, which supports computational research tightly integrated with educational and outreach activities aimed at broadening the palette of currently available photocatalytic materials. Solar energy is the most abundant energy source available to humankind, but this energy cannot be harnessed on demand due to the variability of sunlight. This CAREER award supports research and education in the specific area of artificial photosynthesis, which emulates natural photosynthesis, the sunlight-driven process used by plants to transform the carbon dioxide absorbed by their leaves and the water pumped by their roots into organic nutrients for supporting their survival and growth. Using artificial photosynthesis, carbon-neutral fuels can be produced. By developing accurate computer models to predict the chemical transformations that underlie artificial photosynthesis, the PI and his research team aim at answering critical questions that surround the fuel-production ability of a promising family of materials that have been shown to absorb a much larger portion of the solar spectrum than previously used materials. The outcome of this research will be to expand the palette of materials that can efficiently operate under sunlight, and develop new software for understanding how small variations in the composition of a given material can affect its ultimate fuel-production performance. The new software will be disseminated to the community through an open-source distribution. This CAREER award also supports a comprehensive educational and outreach plan to increase the participation of women and underrepresented groups in science and engineering with an emphasis on exposing them to the universe of computer programming and simulation, on developing effective teaching materials to train a computationally literate generation of young scientists and engineers, and on accelerating the emergence of a diverse and well-trained workforce in the area of materials modeling in an effort to reduce the time and cost involved in the industrial development of new energy materials. TECHNICAL SUMMARY The Division of Materials Research and the Division of Chemistry provide funding for this CAREER award, which supports computational research tightly integrated with educational and outreach activities aimed at broadening the palette of currently available photocatalytic materials. Solar energy is the most abundant energy source available to humankind, but this energy cannot be harnessed on demand due to the variability of sunlight. Artificial photosynthesis provides a sustainable way to overcome that variability through the direct photocatalytic storage of solar power into chemical fuels; however, most of the stable photocatalysts in use today rely on metal oxide semiconductors whose bandgap does not match the solar spectrum, which greatly limits their overall performance. By developing accurate molecular and submolecular models of electrochemical reactions at the interface between a semiconductor and an electrolyte under realistic environmental conditions, the PI and his research team aim to understand, predict, and control the surface mechanisms that underlie the operation of photochemical reactors towards maximizing their fuel-production performance. This CAREER project is specifically focused on studying layered metal oxide photocatalysts that can operate optimally under sunlight. In order to predict the properties of promising layered semiconductors, the PI will exploit and further develop a newly released quantum-continuum model to perform large-scale simulations of semiconductor-solution interfaces at finite temperature, taking into account the adsorption of ions and the response of explicit water layers under applied voltage. New software will be created in the open-source Quantum-Espresso distribution to provide the computational community with a widely applicable and highly transferable modeling framework for future studies of photocatalytic mechanisms at electrified photoelectrodes. This CAREER award also supports a comprehensive educational and outreach plan to increase the participation of women and underrepresented groups in science and engineering with an emphasis on exposing them to the universe of computer programming and simulation, on developing effective teaching materials to train a computationally literate generation of young scientists and engineers, and on accelerating the emergence of a diverse and well-trained workforce in the area of materials modeling in an effort to reduce the time and cost involved in the industrial development of new energy materials.