Catalyst surface energy control through defect formation and its application to electrochemical carbon dioxide reduction and hydrogen storage

Abstract

Greenhouse gas emissions due to the use of fossil fuels are rapidly increasing, and accordingly, abnormal climate and disasters are occurring worldwide. As a result, countries around the world are scrambling to develop various technologies in related fields to make efforts for carbon neutrality. In this dissertation, among various technologies for carbon neutrality, research on catalyst materials used for converting chemical energy into electrical energy or in the opposite reaction was dealt with. In the catalyst field, efforts are being made to increase catalytic activity through various studies. This can be largely divided into two strategies, a strategy that increases the catalyst active site or increases the intrinsic activity of the catalyst. The both strategies interact complementary to each other rather than using only one strategy selectively, resulting in a synergistic effect. In addition, in the catalytic reaction, substances participating in the reaction undergo physical or chemical adsorption on the surface of the catalyst, electron transfer, and product desorption. Therefore, it can be said that it is very important to control the binding energy between materials participating in the reaction, such as reactants, intermediates, and products, and thesurface of the catalyst. It is a widely known fact that the highest catalytic activity is achieved when materials and catalysts have appropriate binding energies. Therefore, in this dissertation, a method for controlling the surface energy of a catalyst was studied by generating defects using plasma treatment or potassium hydroxide activation on the catalyst surface. Then, it was applied to electrochemical carbon dioxide conversion and hydrogen storage materials. As a result, it was possible to convert carbon dioxide into a high value-added material with high efficiency, and it was possible to synthesize a hydrogen storage material with high storage capacity. In addition, through experimental data analysis and density functional theory calculation, a study on the mechanism for high performance was also conducted. As such, this dissertation proved that the catalytic activity can be increased through surface defect generation using a surface treatment method that is easier than the conventional method. In addition, the possibility of application to other catalytic materials as well as related fields such as electrochemical carbon dioxide conversion and hydrogen storage materials was presented.