top of page
Nanomaterial Catalysts for
Sustainable Energy Technologies
Electrochemical CO2 Reduction Catalysis and Device Integration
Artificial photosynthesis provides the opportunity to store renewable sources of energy (solar, wind, hydro) in the form of chemical bonds by electrochemically converting carbon dioxide into valuable fuels and chemicals. Advancing these technologies to the point they are techno-economically viable will provide means to close the carbon cycle by preparing carbon-neutral or even (ideally) carbon-negative fuels and chemicals. The Higgins group focuses on the development of nanostructured CO2 reduction catalysts with carefully tuned compositions and structures to gain a fundamental understanding of this important electrochemical reaction. Furthermore, catalyst integration into working artificial photosynthesis prototype devices to achieve high conversion rates, energy efficiency and product efficiency is an ongoing effort.
Amirhossein (Kora) Rakhsha
Amirhossein Foroozan Ebrahimy
Supercapacitors are energy storage devices that have attracted much attention due to owning outstanding properties including high power density and rapid charge and discharge cycles. Supercapacitors use two main mechanisms to store charge: I) electrical double layer II) pseudocapacitance. These devices can be employed for various applications, such as electric vehicles in the automotive industry. Their major drawback is low energy density that needs to be resolved. Redox-active conductive polymers can provide promising energy densities as supercapacitor materials. Therefore, in the Higgins group, the focus is on:
• Novel synthesis of scalable, cost-effective conductive polymer materials grown on conductive carbon
• Advanced characterization of synthesized polymeric materials to understand the structure and underlying mechanism by the correlation with electrochemical performance
• Electrochemical performance evaluation of polymeric materials to ensure energy storage capacity and Coulombic efficiency (i.e., stability during charge/discharge cycles)
Batteries play a critical role in supporting the rapid transition to a sustainable energy sector, a major effort in the current fight against climate change. Strategies to reduce carbon emissions from the energy sector involve an increased deployment of renewable energy production (solar and wind). However, the intermittent nature of renewables requires stationary energy storage systems capable of reliable energy dispatch at the grid-level. Much like the electrified mobility market, lithium-ion batteries have, as of now, been the most popular option for utility scale energy storage installations. However, lithium may not be a one-size fits all solution to our growing need for stationary energy storage where cost, safety, and durability are more important metrics than the weight of the battery. Considering this along with the rising cost of raw materials, an increasing frequency of supply chain disruptions, and the growing demand for energy storage installations, it is important that we acknowledge the diversity of technologies which may be better suited for stationary applications.
Zinc-ion batteries are a promising alternative to lithium, one that is particularly well equipped for stationary applications. Offering many advantages including improved safety, use of inexpensive raw materials, and minimal environmental impact. ZIBs may play an important role in decarbonizing the grid and enabling use of variable renewable energy sources. The Higgins group is mainly focused on improving the performance (i.e., capacity, lifetime) of ZIBs through the design and development of new positive electrode materials, with an emphasis on the scale-up and commercialization potential of the technology.
Caio Miranda Miliante
Electrochemical conversion of glycerol
Glycerol, side product of the biodiesel production, can be found in huge amount with low cost. The increase in biodiesel production has led to an overproduction of glycerol. The excess of glycerol has not only reduced the efficiency of biodiesel production by increasing the cost of storage and disposal but also has become an environmental problem. In this context, electrochemical conversion of glycerol is an environmentally friendly method and increases the economic value of glycerol by producing value-added chemicals. Valorization of glycerol is of great importance in terms of providing the opportunity to support the continuance of biodiesel production. The Higgins group aims to develop stable and active catalyst for glycerol electrooxidation reaction (GOR).
Ecem Yelekli Kirici
Operando/in situ characterization of electrocatalyst and electrode materials
Understanding the role that the physical and chemical properties of nanomaterial catalysts and electrode structures have on performance is crucial for the discovery/design of new materials. Ex situ characterization of materials is not always reflective of the material properties during operation. Therefore, our group uses a variety of in situ / operando microscopic and spectroscopic approaches to gain an accurate understanding of the important factors that govern catalytic activity, selectivity and stability.
Fuel Cell Catalysis (Oxygen Reduction Reaction)
Low temperature fuel cells hold promise for enabling a sustainable transport sector that operates off of zero-emissions hydrogen produced by renewable means (i.e., electrolysis). Current challenges hindering widespread deployment of fuel cells are cost and stability challenges arising from the Pt-based oxygen reduction reaction (ORR) catalysts used at the cathode. It is essential to reduce Pt contents by achieving catalyst activity improvements while simultaneously improving the long-term operational stability. The Higgins group focuses on the development of low-Pt or Pt-group metal free (PGM-free) catalysts and their integration into operational fuel cells.
Electrochemical Water Splitting Catalysts
Electrochemical water splitting using renewable electricity (solar, wind, hydro) provides sustainable means for producing hydrogen. Hydrogen has many industrial uses, including fertilizer (ammonia) production, petrochemical processes and as a carbon-free fuel. Particularly, hydrogen fuel cells have the potential to transform the transportation sector. Operating on hydrogen produced renewably, fuel cell powered automobiles have the potential to reduce greenhouse gas emissions by as much as 90% in comparison to conventional internal combustion vehicles. In order to produce hydrogen, we need to develop catalysts for the oxygen evolution reaction (OER) which is the main obstacle to hydrogen production. The Higgins group is focusing on developing low-content PGM catalysts for acidic OER and trying to find the appropriate protocols for electrodes with small areas (such as rotating disk electrodes (RDE)) which can mimic industrial results such as membrane electrode assemblies (MEA), using machine learning.
Developing atomically dispersed catalysts for nitrate conversion to ammonia
Ammonia is a valuable chemical used in fertilizers and critical to maintaining our food systems. It has the potential to be a low-carbon energy storage medium, liquid fuel, and hydrogen carrier. Currently, ammonia is produced by the Haber-Bosch process, which is both resource and energy-intensive. It operates at high pressures (150-300 bar) and temperatures (400-500 ◦C) therefore requiring 1-2% of the global energy supply and producing over 1% of CO2 in the world. Sustainable and green ammonia production is critical to achieving clean energy production and storage. The electrochemical reduction of nitrogen-containing chemicals to produce ammonia is a sustainable and environmentally friendly alternative to the Haber-Bosch process. Nitrate pollution is found in municipal, agricultural, industrial, and low-level nuclear wastewater, and is a growing problem. The solubility in water and low N-O binding energy (204 kJ mol-1) of nitrate has attracted interest in recent years as a promising sustainable approach to produce ammonia.
bottom of page