Our research efforts are dedicated towards tackling the energy challenge facing today's society. If we want to maintain our current standard of living without further polluting the planet we live in, new methods must be developed to utilize renewable energy sources in place of fossil fuels. Specifically, our lab's focus is to develop and understand solar to chemical conversion. The long term goal here is to be able to efficiently absorb and store solar energy as fuels and value-added chemicals. To do so, improved materials must be developed to carry out these transformations. Towards this end, we utilize electrocatalysis and biocatalysis. Doing so, we utilize an iterative cycle of 1) materials design to solve a specific issue, 2) synthesis and characterization of the aforementioned material, 3) implementing spectroscopy and analytics to elucidate how the materials function and 4) developing structure-function relationships and lessons to feed into the next cycle of materials design.
Metal Organic Frameworks
Catalyst development for renewable energy utilization is a pressing global issue. The goal for this research program is to investigate electrocatalytic metal organic frameworks (MOFs) with rationally designed three dimensional catalytically active pockets for conversion of electricity to fuels and chemicals. MOFs are permanently porous structures, combining organic linkers and inorganic nodes, which can be rationally designed to attain optimal performance. Of particular interest is the inclusion of functionalities that render enzymes so efficient via the utilization of stabilizing ligands grafted within the framework, proton shuttles, cavity hydrophobicity, and tandem catalysis within confined environments. The objective is to demonstrate that efficiently driving reactions from CO2 and H2O starting materials to the desired products (i.e. CH3OH, CH4, CH3CH2OH…) can be accomplished by establishing MOF-based electrochemical systems that incorporate enzyme-inspired reaction effects.
Nanomaterials and Plasmonics
In order to develop pathways towards widespread utilization of renewable energy, new generations of catalytic materials must be developed. The design, synthesis, and characterization of functional materials must be carried out with a focus on the nanoscale. The purpose of this is two-fold: 1) Many of the fundamental phenomena is solar to chemical transformations occur at the nanoscale. These include light absorption, surface reactions, electronic interactions, and solvent-substrate interactions. 2) When scaling down to the nanoscopic domain, many materials exhibit uniquely different properties than the same materials in the bulk. Such new properties can used for real-world applications or as a handle to study the underlying science at hand. Our aim is to discover and exploit new nanoscopic materials and effects such as enhanced surface electric fields at the plasmonic particle-electrolyte interface to solve pressing energy-related challenges.
Biocatalysts and Hybrid Systems
We look to biology as an inspiration and as highly functional tool to do what our synthetic materials cannot yet do. As a source of inspiration, we study how biological processes proceed with the high precision and efficiency we hope to eventually achieve with our man-made materials. Doing so, we view at a fundamental level the intricate function of of biological workings. Most relevant to my work are enzymes, the catalysts employed in nature to carry out chemical transformations. At a more complex level are multi-component functional systems such as living cells and small organisms. Electrochemistry and spectroscopy are two important handles we can use to gauge structure and function of these systems.
On a more applied level, we can take advantage of highly developed biological systems to carry out energy transformations for us. Utilizing inorganic-biological hybrid systems we can more transduce energy with higher efficiencies of biological or synthetic materials on their own. For example, we can use semiconductors to absorb light and transfer photoexcited charges to microbes, which subsequently use these charges to carry out thermodynamically uphill reactions.
Spectroscopy, especially when performed in-situ, is essential to understand the underlying chemical processes that occur during our reactions. In order to develop new generations of catalytic materials, we need to understand what makes current state-of-the-art materials highly functional. Such knowledge includes reaction intermediates, charge transfer pathways, active sites, and metastable phases. Once this is deciphered, a rational route to improved materials can be developed. To gain the insights we desire, we 1) apply well-established methodology to new systems or 2) develop the techniques necessary to extract a new level of insight from our materials of interest. Specifically, we utilize in-situ and operando techniques include Raman, infrared (IR), UV-Vis-NIR absorption, transient-absorption and X-ray absorption (XAS) spectroscopies, quartz-crystal microbalance (QCM) analysis.