Dual-Function Materials for CO2 Capture and Conversion into Methanol and Higher Alcohols
The goal of this project is to synthesize, characterize, and evaluate materials capable of both capturing carbon dioxide (CO2) and catalyzing its conversion to value-added chemicals. Specifically, capture and conversion at the exhaust of combustion sources (e.g., flue gas at power plants) is an attractive option for CO2 valorization due to its simultaneous economic and environmental benefits. To achieve more efficient CO2 conversion, the project will design novel materials that locate the sorbent and catalytic components in close proximity at the nanoscale. This dual-function approach can potentially replace existing multi-step processes that are more energy intensive and require corrosive CO2 capture and storage technologies.
This project will advance the understanding of mechanisms involved in one-pot concentration, capture, and catalytic conversion of CO2 to methanol and other value-added products, a strategic goal for sustainable reduction of CO2 release to the atmosphere.
Soluble and Reusable Polymer-Based Catalysts for the One-Pot Synthesis of HMF or Levulinic Acid from Glucose
The goal of this project is to develop soluble and reusable polymer-based catalysts with Brønsted and Lewis acid sites for the one-pot synthesis of hydroxymethylfurfural (HMF) or levulinic acid from glucose. Being soluble makes the catalyst very active because the reactants are easily accessible to all active sites. In addition, deactivation through coking is avoided because there is no physical surface for carbonaceous species to be deposited. On the other hand, the catalyst can be easily recoverable by ultrafiltration and be reused due to its high molecular weight.
HMF is primarily produced as a platform molecule to be converted into other value-added products. One of the most important is 2,5-furandicarboxylic acid (FDCA), which is a precursor of a renewable plastic called polyethylene furanoate (PEF), and has been proposed as a replacement for terephthalic acid in the production of polyesters. Likewise, the increasing use of levulinic acid in different applications, such as plastics, nylons, and rubbers is expected to boost the demand even more in the coming years.
Control of Catalyst Deactivation through Encapsulation Using Wet Chemical Methods
Different methods have been explored over the years in an attempt to overcome the problems associated with catalyst deactivation. Some of those techniques include Atomic Layer Deposition (ALD), Chemical Vapor Deposition (CVD), Strong Metal-Support Interaction, and core-shell methods. ALD has particularly received increased attention due to its potential to prevent leaching and sintering in base metals (e.g., copper) for liquid phase reactions. Although ALD is effective, it makes use of expensive precursors and high vacuum, and it is time consuming. SMSI has also been used to encapsulate catalysts to protect them from deactivation. However, SMSI is extremely selective, as not all metal oxides show this phenomenon, which limits its application. The challenges associated with these and other approaches propelled our desire to develop a facile and more economically viable process.
We have recently developed a wet chemical method to grow an alumina overcoating layer onto silica spheres, and this has been further optimized to control its thickness. Future efforts will be geared towards utilizing this method to encapsulate metal nanoparticles to prevent their deactivation through leaching and sintering, which are predominant modes in aqueous systems.
Development of Nanocomposites for the Detection of Hydroxyl Radicals (with Dr. Kim, UToledo)
Free radicals are extremely reactive and unstable chemicals generated from various sources like biological metabolism and atmospheric reactions. Overproduction of free radicals, such as hydroxyl radicals, in a human body, is known as one of the causes for accelerated aging, cancer, Alzheimer's disease and multiple sclerosis. Therefore, a rapid and efficient detection of free radicals is essential for the prevention and cure of these diseases. Several methods have been used for the detection of free radicals; however, most of them are not accurate and consistent enough in identifying the type and concentration of free radicals. The goal of this project to make a highly sensitive, robust, and reusable sensor for hydroxyl radicals. The sensor is regarded as greatly beneficial not only for medical diagnosis, but also for fuel cells, and environmental monitoring.