B.S., 2008, Fairfield University
Ph.D., 2013, Stony Brook University and Brookhaven National Laboratory
Postdoctoral Associate, 2013 - 2015, Yale University
Office: JMH 514
Research Laboratory: JMH 502
Chemistry of Nanomaterials
Chemistry of the Environment
My group's research interests focus on the synthesis and characterization of new nanostructured materials with applications in renewable energy devices and sensors. Our main objective is to tailor the physical and chemical properties of these materials: such as their size, morphology (shape), composition, and structure to improve the performance of these materials for their intended application.
We focus our efforts on two key research frontiers including:
- Renewable energy devices such as fuel cells, solar cells, and photocatalysts.
- Sensor technology for biologically relevant molecules such as ethanol and glucose.
Nanotechnology in Context
Nanotechnology is a new and exciting interdisciplinary research frontier that is enabling rapid development in a broad range of commercial technologies. Nanomaterials are characterized by their extremely small size and are defined as any material that possesses at least one geometric dimension (e.g. length, diameter, or thickness) that is between 1 and 100 nanometers (nm). To place the nanometer length scale into perspective, one nanometer is equivalent to 1 billionth of a meter (1 × 10‑9 nm) and is equivalent to the thickness of a single strand of DNA. Nanomaterials have many interesting properties that arise from their small size and high surface-area-to-volume ratio. My group is interested in designing and synthesizing nanomaterials with properties that are tailored for specific applications in renewable energy and sensing technology.
Visualizing Nanomaterials with Electron Microscopy
The scanning electron microscope (SEM) image depicts a collection of 50 nm platinum-based nanowires. The nanowire were synthesized by Fordham University undergraduate researchers using an ambient solution-based technique. Powder X-ray diffraction performed on our Bruker D8 Advance Eco diffractometer confirms their purity and crystallinity.
Nanomaterial Synthesis & Characterization
Although there are many methods to synthesize nanomaterials, our group focuses on safe, efficient, benchtop methods to produce high quality nanomaterials. A key area of interest is the development of solution-based methods for the synthesis of nanostructures including template-assisted, hydrothermal, and solvothermal techniques. We aim to not only produce high quality nanomaterials but to also optimize these synthetic protocols so that the size, shape, and structure of the resulting particles can be predictably controlled. In essence, we synthesize nanomaterials to our own specifications. For example, tuning the morphology and composition of platinum-based nanowires has led to significant improvements in the sensitivity and selectivity for the electrochemical oxidation of small organic molecules.
At Fordham University, we have a wide range of synthesis tools and analytical instrumentation to characterize the properties of nanostructured materials including:
- A Scanning Electron Microscope (SEM) with Energy Dispersive X-ray Spectroscopy (EDX) Capabilities
- X-ray Diffraction (Powder and Single Crystal)
- Atomic Force Microscopy
- Thermogravimetric Analysis
- UV-visible and Fluorescence Spectrometers
- Fourier Transform Infrared Spectrometer (FTIR)
- Raman Spectrometer
- A Bipotentiostat and Rotating Disk Electrode for Testing Fuel Cell Catalysts
- A Full Spectrum Solar Simulator for Testing Solar Cell Devices
- Box Furnace
- Hydrothermal & Microwave Reactors
I. Nanomaterials for Renewable Energy
There has been a recent and growing demand for green, renewable energy sources to replace fossil fuels. Our group focuses on two key areas in renewable energy:
i.) Converting sunlight into electricity and fuels using photoelectrochemical cells: A promising approach to satisfying our nation’s energy needs is to convert solar energy either into electricity or directly into renewable fuels such as hydrogen. However, the efficiency of these energy conversion processes remains relatively low. In this context, we are focusing our efforts on synthesizing and tailoring the properties of nanostructured metal-containing materials to improve their photoelectrochemical performance in working devices. An important example includes the dye-sensitized photoelectrochemical cell (DSPC) device, which converts solar energy to either electricity or to solar fuels.
Converting Solar Energy to Electricity with DSPCs: Light from the sun is absorbed by a dye molecule leading to the excitation of electron from the ground state to the excited state. This excited electron is captured by the metal oxide nanoparticles that the dye is attached to and is passed through an external circuit producing electricity. The circuit is completed by an electrolyte with an iodine containing redox couple. These devices (right image) can be prepared in our laboratory using simple assembly techniques and have efficiencies of up to 9%. (Ref: Chemistry of Materials, 2011, 23, 3381-3399. Copyright 2011 American Chemical Society)
ii.) Utilizing renewable fuels to power homes and automobiles with fuel cells: The electrochemical oxidation of the fuel and reduction of oxygen is facilitated by catalysts, which typically consist of small (2 – 4 nm) spherical platinum nanoparticles. Although platinum is the best element to catalyze the reactions, platinum’s extremely high cost and low abundance prevents large scale use of platinum in fuel cells. Our interest is in designing new fuel cell catalysts that have higher catalytic activity and better long-term durability, while utilizing abundant and less expensive metals. We accomplish this task by tuning the size, shape, and composition of the catalyst itself to improve overall performance.
Hollow Nanoparticles in Action as Fuel Cell Catalysts: The image on the left depicts a high angle annular dark field (HAADF) TEM image of a 12.5 nm hollow Pt-Ag nanoparticle. The energy dispersive X-ray maps show that the Pt and Ag components are uniformly mixed in the particle’s shell. The hollow particples were found to have more than five-fold higher catalytic activity toward the oxygen reduction reaction than state-of-the-art commercial Pt nanoparticles. (Ref: RSC Advances 2017, 7, 46916-46924 – Reproduced by permission of The Royal Society of Chemistry)
II. Electrochemical Sensors - Detecting Biologically Relevant Small Organic Molecules
The high cost of precious metals has also hindered their widespread use as electrocatalysts for the oxidation and detection of small organic molecules such as ethanol and glucose. Thus, the development of cost-effective electrocatalysts can have broad commercial implications and can contribute to broader global challenges in energy and health care costs. We are focusing our efforts on developing new nanostructured architectures as cost-effective catalysts with high sensitivity and selectivity for a wide range of small organic molecules.
Banerjee, S.; Liu, C.H.; Lee, J.D.; Kovyakh, A.; Grasmik, V.; Prymak, O.; Koenigsmann, C.; Liu, H.; Wang, L.; Abeykoon, A.M.M.; Wong, S.S.; Epple, M.; Murray, C.B.; Billinge, S.J.L., Improved Models for Metallic Nanoparticle Cores from Atomic Pair Distribution Function (PDF) Analysis. The Journal of Physical Chemistry C. 2018, ASAP (DOI: 10.1021/acs.jpcc.8b05897)
Shutang, C.; Thota, S.; Singh, G.; Aímola, T. J.; Koenigsmann, C.; Zhao, J., Synthesis of Hollow Pt-Ag Nanoparticles by Oxygen-Assisted Acid Etching as Electrocatalysts for the Oxygen Reduction Reaction. RSC Advances 2017, 7, 46916 – 46924.
Colliard, I.; Koenigsmann, C., One-Dimensional Nanostructured Catalysts for the Oxygen Reduction Reaction. In One-Dimensional Nanostructures for PEM Fuel Cell Applications, 1st ed.; Pollet, B. G., Ed. Elsevier: London, United Kingdom, 2017; pp 19-48.