While the fleet of electric vehicles (EVs) is rapidly growing, the transition to fully electric mobility concepts critically depends on the available battery technology. In particular, solid-state batteries are the key enabling technology to produce reliable and safe EVs. Paramount to high performance solid-state batteries are solid-state electrolytes (SSEs) with high Li-ion mobility. However, the vast chemical design space for SSEs impedes trial-and-error approaches, but it provides ample room for data-driven discoveries. I will briefly discuss our initial attempts to use machine-learning for materials design and emphasize the need for suitable material representations (descriptors or fingerprints).
Despite the quickly growing market for EVs, fossil fuel powered vehicles with modern engine technologies will continue to dominate our roads for the near future. Low temperature combustion (LTC) diesel engines have higher fuel efficiency and produce less NOx and particulate matters (PM) compared to traditional diesel engines. Similarly, natural gas vehicles (NGVs) are relatively clean and emit less CO2 compared to gasoline-powered cars. To leverage the benefits of these new engine technologies, they need to be paired with an advanced emission aftertreatment system. LTC engines require cold-start solutions and a low temperature diesel oxidation catalysts (DOC) that can cope with higher concentrations of CO and unburned hydrocarbons (HC). NGVs require modified three-way catalytic converters that can also oxidize methane; we refer to them as four-way catalytic converters (FWC).
To address cold-start NOx emissions, we study Pd-exchanged zeolites as passive NOx adsorbers (PNAs) to store NOx at low temperature and release it at higher temperature to a downstream DOC to adjust the NO/NO2 ratio, followed by a reduction catalyst, which converts NOx to N2. We have also used computational screening for rapid catalyst discovery for DOC and FWC oxidation catalysts. Guided by our simulations, we have developed a dual-stage DOC prototype alloy catalyst and reactor configuration, which is able to meet the Department of Energy 150 C challenge for CO oxidation in mixtures of CO/NO, CO/C3H6, CO/NO/ C3H6, and even CO/NO/C3H6/H2O. Similarly, we have optimized FWCs comprised of platinum group metals (PGM) and spinel oxides as dynamic oxygen storage materials.
Collectively, these significant, computationally driven advances are expected to accelerate the transition to modern and sustainable vehicle fleets.
Prof. Lars Grabow is the Dan Luss Professor in the William A. Brookshire Department of Chemical and Biomolecular Engineering at the University of Houston. He holds a courtesy appointment in the Department of Chemistry and is a Member of the Texas Center for Superconductivity at the University of Houston (TcSUH). He received his PhD in Chemical Engineering from the University of Wisconsin in 2008, followed by postdoctoral appointments at the Technical University of Denmark and Stanford University. His expertise is the application of electronic structure calculations, kinetic modeling, data science and transient kinetic characterization to problems in heterogeneous catalysis, surface science and electrochemical energy storage. His papers have been cited more than 5,000 times and he was elected into the 2018 Class of Influential Researchers by Industrial and Engineering Chemistry (IE&C) Research. Prof. Grabow won the prestigious U.S. Department of Energy (DOE) Early Career Award (2014) and the NSF CAREER Award (2015), the Excellence in Research Award at the assistant professor level from the University of Houston (2017). Currently, he serves as Chair of the Southwest Catalysis Society (SWCS) and as Editor of Surface Science.
He served as (Vice/Past) Chair of the AIChE Catalysis and Reaction Engineering (CRE) Division and continues to serve as Social Media Director. He is a member of the International Advisory Board of ChemCatChem, the Editorial Advisory Board of Surface Science, and a past member of the Early Career Advisory Board of ACS Catalysis.