Welcome to the Z-Energy Group! We are passionate about the design, synthesis, and testing of novel materials for energy and propulsion applications. Our research involves fundamental studies of thermodynamics, materials, and chemistry. Our current research has three general directions. First, we continue to develop ultrafast flame-based methods to synthesize novel nanomaterials, especially metal oxides. Second, we are developing electrocatalysts and devices to split water into H2, O2, and H2O2. Finally, we are developing new metal/polymer composites as high-energy-density fuels for propulsion applications.
Research on converting water to fuels using sunlight has been ongoing since the 1970s, as it enables both storage and transport of solar energy in the form of chemical bonds. Conventional schemes have aimed to produce hydrogen and oxygen via water splitting within an electrochemical cell. Focusing on the anode of the cell, our group has worked toward extending this concept to produce hydrogen peroxide rather than oxygen gas as a product. Whereas oxygen is typically an unused byproduct of water splitting, the production of hydrogen peroxide is advantageous as it can be used both as a fuel and as a water purification agent. However, the voltage necessary to generate hydrogen peroxide from water (1.76 V) is substantially higher than what is needed to generate oxygen (1.23 V). Accordingly, our group is working to develop metal oxide catalyst materials that are highly selective toward hydrogen peroxide production.
Data-driven approaches in materials research
Data-driven approaches have suggested novel ways in science and engineering research based on accumulated scientific data with advances in data science, machine learning algorithms, and computing power. Machine learning-assisted, data-driven approaches can provide a comprehensive way to investigate feature-property relationships in material systems with unknown governing equations. Our group uses data-driven approaches along with traditional mechanics-driven approaches in our research to answer scientific questions.
Combustion of Energetic Materials
Metal-based energetic materials (e.g., Aluminum and Boron) have extremely high volumetric and specific energy densities, so they have a broad range of applications ranging from propulsion, pyrotechnics, and material synthesis to thermal energy generation. However, metal-based energetic materials have high temperatures/energies, long ignition delay time, and incomplete combustion, which limits their energy release rate and efficiency. To address these challenges, our group synthesizes novel nanostructured energetic materials (e.g., core/shell, surface functionalization) and uses nanomaterial additives (e.g., graphene oxide, graphene fluoride, porous Si) and studies their impacts on the ignition and combustion performance of metal-based energetic materials. We have successfully demonstrated that those approaches are effective in lowering the ignition temperatures, ignition delay time, and improving the heat release rate and overall heat release of metal fuels and energetic composites.
Silicon nanowires for energy and environmental applications
Our group develops metal-assisted chemical-etched silicon nanowires array fabricated through nano-imprint lithography method that enables the applications in thermoelectric power generator, hydrogen generation, and OH radical generation fields that were not accessible before. Silicon is abundantly available on earth and the silicon nanowire array-based thermoelectric devices through nanosize engineering and doping double the efficiency of the current ~5% thermoelectric generation efficiency, and such devices can be applied in converting waste heat into electricity. Easy-to-fabricate silicon nanowire arrays with a large surface area and high aspect ratio can generate hydrogen gas on demand by reacting with water. The mechanical stable high-quality silicon nanowire arrays are also good substrates for photocatalysts which enables OH radical generation that helps in organic dye degradation in the wastewater treatment.