Office: JSCBB C224
Mailbox: 596 UCB
B.S., University of Cincinnati (1976)
M.S., Ph.D., University of Colorado (1978, 1980)
Dow Chemical Company(1980-1996)
Particle Surface Modification; Solar-thermal Processing; Energy Materials
Particle Surface Modification:
There is an interest in functionalizing high surface area fine particles by controlling their surface chemistry while maintaining bulk properties. A powerful method co-invented/developed in the lab is to use atomic layer deposition (ALD) to deposit nearly perfect ultrathin nano-thick films at angstrom level precision onto primary particles, i.e. Particle ALD. A current focus in the lab includes developing a fundamental understanding of the fluidized bed reactor process used to carry out the coating and improving the process as well as expanding the applications. Additional focus is directed towards materials useful for protecting nuclear fission materials and thrust segments for travel to Mars and beyond the solar system. Investigation also includes improving materials for PEM catalysts and solid oxide fuel cell ionic conductivity. Applications vary and include catalysis, micro-electronic devices, pigments, sunscreen materials, nuclear materials, separations media, printed inks and the development of porous thin films with angstrom control of pore diameter. Students in the lab have pioneered Particle ALD innovation and have been recognized with cover articles in Nanotechnology, best dissertation awards in the College of Engineering and Applied Science and the Best Ph.D. in Particle Technology Award by the American Institute of Chemical Engineers.
Ultra-high temperatures above 1200oC can be achieved using concentrated sunlight. Such heating can be used to drive thermal dissociation/cracking type chemical reactions where intermediate products are undesirable and where such high temperatures thermodynamically favor the desired reaction products. Two such reactions currently being investigated include the gasification/pyrolysis of biomass and splitting of water, carbon dioxide or mixtures to produce hydrogen or intermediate synthesis gas which can be subsequently reformed to fungible liquid fuels. Current research is focused on improving fundamental understanding of the process and optimal design of solar-thermal chemical reactors/receivers. Projects include CFD modeling of multi-tubular reactor systems, the evaluation of materials suitable for solar-thermal processing and the control of such processes. Solar reactors are designed and built in the lab/shop on skids and then transported to the National Renewable Energy Laboratory (NREL) where experiments are carried out on-sun at the High-flux Solar Furnace. Additional experiments are carried out at CU using electrically heated reactors of using CU’s unique high-flux solar simulator with integrated hybrid solar/electric receiver. Models are being developed to complement the experiments and to develop an understanding of the reaction kinetics and heat transfer in such processes. The design and demonstration of solar-thermal chemical reactors is a key core competency of the lab, which is one of the only such locations for this expertise in the world.
Efforts are also underway to discover/invent robust active materials for redox reactions to split water and carbon dioxide, producing H2 and CO. Materials of interest include spinels and perovskites with reduction reaction targeted for less than 1400oC and where O-vacancy reaction mechanisms allow for robust cycling while avoiding liquid phase sintering. Computational research within the Musgrave research group complements experimental validation using stagnation flow reactors and high temperature thermogravimetric analyzers. Novel surface science characterization of low – cycle (less than 6 ALD cycles) ALD film deposition on Li-ion battery cathode materials is being used to elucidate that true mechanism for improved battery lifetime and cycling stability is through preferential growth that stabilizes the transition metal oxides in the presence of electrolyte without blocking lithium intercalation pathways. Efforts are also being directed towards novel CVD processing to synthesize carbon nanotubes/nanofibers and hydrogen from methane at low cost using a scalable process. Additional efforts are directed towards using a sacrificial substrate to synthesize extended surface catalysts for PEM fuel cells and to capture CO2 from the atmosphere or flue gas stacks using a novel and low cost scavenging material.
Sundrop Fuels Inc. resulted from Dr. Weimer's research; read a related article in Science.
>>Read more about Dr. Weimer's research in solar thermal hydrogen fuel production.