Electrochemical carbon dioxide reduction using pH-dependent cobalt phthalocyanine catalyst

Abstract

Rising atmospheric carbon dioxide (CO_{2}) levels due to fossil fuel combustion poses severe environmental challenges including global warming. Among the CO_{2} capture and utilization methods, this thesis focuses on the electrochemical CO_{2} reduction reaction (CO_{2}RR). Alkaline electrolytes have generally been used in studies in order to suppress the hydrogen evolution reaction (HER) which competes with CO_{2}RR. While high Faraday efficiencies can be obtained in these conditions, the production of carbonate salts is inevitable. Using acidic electrolytes can solve this issue but catalyst performance is still limited in acids. We expect that utilizing pH-dependent electrocatalysts can improve the efficiency of CO_{2}RR in acidic conditions, and in this thesis, we study the characteristics and performance of carbon nanotube-supported cobalt phthalocyanine catalysts (CoPc-CNT) in various electrolyte environments.