KOSEN 한인과학기술자네트워크

Rational Design of Energy Materials and Catalysts: from Computational Chemistry to Experimental Validation

During the past decade theoretical description of science and engineering phenomena has undergone a dramatic development. Today’s advances in computational capabilities and algorithms mean that it is now possible to design new materials with properties tailored to specific applications within the detail and accuracy required for computational results to compare with experiments. The fundamental understanding of correlation between materials structure and properties is a key to design new materials with desired properties. Using computational methods such as a state-of-the-art Density Functional Theory (DFT) calculations, the major focus of our research efforts is on the discovery of materials with desired properties for a wide range of important applications as described below.

I. Materials Design for Solid Oxide Fuel Cell (SOFC)

Due to the continuous expansion of world population and industrialization, energy demands in modern society are rapidly increasing while fossil fuels are being exhausted. This challenge has been a driving force to develop sustainable energy production systems alternative to the conventional fossil fuel combustion. Among the various types of alternative technologies, solid oxide fuel cells (SOFCs) have been particularly attractive due to their fuel flexibility and high energy conversion efficiency. Recent efforts for SOFC development have focused on lowering the operating temperatures to 500~800°C to improve chemical and mechanical stability and reduce the cost. For this purpose, we will design the electrolyte and cathode materials with the enhanced properties at the intermediate temperatures.

II. Liquid Organic Hydrogen Carriers as a Renewable Storage and Transport

Hydrogen can be utilized in fuel cells or in internal combustion engines, and lower-cost fuel cells are being developed. However, there are a number of issues to be addressed for efficient hydrogen storage. To overcome storage limitations associated with elemental hydrogen, reversible hydrogen storage by means of chemical bonds is proposed to be a promising solution. In this strategy, an H2-lean molecule is hydrogenated at a site of abundant, cheap hydrogen, to give the corresponding H2-rich molecule, which can be stored for extended periods and transported by using present energy transport infrastructures. H2 is finally released at energy demand sites through catalytic dehydrogenation, regenerating H2-lean molecule, which can go back to H2 supply sites for repeated use in energy storage. In such “chemical storage” systems, liquid organic hydrogen carrier (LOHC) materials can be utilized.

III. Rational Design of Catalysts for Methane Direct Conversion

Among the environment-friendly and renewable energy sources that can replace petroleum, methane is a promising transitional energy source, which can be converted to high value chemicals, such as methanol, ethane etc. through chemical process. However, the process of converting methane has considerable challenges that should overcome low selectivity and activity. This is because the product is more reactive than methane during the conversion. Therefore, we will study the catalytic properties of the methane direct conversion reaction using state-of-the-art computational materials science method and report the appropriate catalytic materials.

 

IV. Automobile Exhaust Catalysts Operating at Low Temperature

As the regulations for automobile emission are strengthened, there is a growing demand for highly efficient catalysis at low temperatures. The automobile vehicles release mainly three pollutants, NOx, CO, and hydrocarbons, into the atmosphere. In this project, we will develop suitable catalysts to remove the CO. The precious metals often have high activity of CO conversion, but they are uneconomical due to the high cost. Ceria (CeO2) is one of the most widely used materials as diverse oxidation catalysts or electrolytes of solid oxide fuel cells due to its high oxygen storage capacity and high stability over a wide range of temperatures. The lattice substitution with inexpensive metals into CeO2 support can be one route to increase the low temperature activity with economical consideration.