Engineering the Morphology & Interface of Nano-sized metal oxides for Highly efficient Energy Devices

Department of Energy EngineeringAs the world population has surged and industrialization has increased, energy consumption has increased day by day, and recently more than a million terajoules of energy have been consumed per day. Demand for renewable and clean energy devices such as solar cells, fuel cells, wind power generators and geothermal generators is increasing as interest in environmental issues accompanied by increased energy demand increases. This change in demand for energy has resulted in a flow of energy sources from existing fossil fuels to clean, sustainable energy sources, especially hydrogen. The hydrogen is the most diverse, clean, efficient fuel and the most abundant element in space, so we focused on the next generation of energy carriers. The hydrogen energy system is constructed and circulated by three parts of energy conversion, storage and reuse. All of devices in hydrogen energy system are based on the electrochemical reactions related to oxygen, hydrogen and water, i.e. oxygen reduction reaction (ORR), oxygen evolution reaction (OER), hydrogen oxidation reaction (HOR), and water splitting reaction. Thus, they have a common problem of slow reaction rate for electrochemical reactions, and the use and development of effective catalysts is mandatory. In these regards, I focused on the nanostructured catalyst having unique mechanical, electrical and optical properties imparted by confining the dimensions. The nanocatalysts is advantageous to achieving excellent electrochemical performances since they have high surface area ???related to reactive site??? to volume. This paper focuses on the understanding and development of energy conversion devices, energy storage devices, and even energy reuse devices, providing comprehensive insight into the overall hydrogen energy system. To realize the high efficiency and overcome the bottlenecks, the nanomaterials were applied and developed with the strategies for each device. I started the basic knowledge including operating principle and theoretical backgrounds for the hydrogen energy systems, nanocatalysts, and materials as follows. 1. Energy Conversion: Scale-down and Sr-doping effects on La4Ni3O10-??-YSZ nanocomposite cathodes for IT-SOFCs 2. Energy Conversion: Nanostructured Double Perovskite Cathode with Low Sintering Temperature for Intermediate Temperature Solid Oxide Fuel Cells 3. Energy Conversion: Tailoring Ni-based catalyst by alloying with transition metals (M = Ni, Co, Cu, and Fe) for direct hydrocarbon utilization of energy conversion devices 4. Energy Storage: Strategy for Enhancing Interfacial Effect of Bifunctional Electrocatalyst: Infiltration of Cobalt Nano Oxide on Perovskite 5. Energy Conversion: Polypyrrole-assisted Co3O4 anchored carbon fiber as a binder-free electrode for seawater batteries 6. Energy Reuse: Self-Transforming Configuration Based on Atmospheric-Adaptive Materials for Solid Oxide Cellsclos