Liquid Metal Catalysts for Electrochemical Reduction of Carbon Dioxide

Rapidly deteriorating environment due to climate change has urged the development of technologies that can effectively address the factors affecting the climate. One such technology is the electrochemical reduction of carbon dioxide utilizing different catalysts. One of the most important setbacks for the conventional solid catalysts is the blocking of their active sites (where reactions take place) as the process proceeds, known widely as coking. This phenomenon decreases the prospects of catalyst utilization in the long term as the reaction efficiency declines with time. The expensive catalysts either need to be replaced or regenerated at regular intervals through energy intensive processes. Thus, there is a constant demand to develop novel catalysts for electrochemical carbon dioxide reduction process. Liquid metal catalysts have recently been explored as a new class of catalysts because of their high melting points, high thermal and electrical conductivity, and versatility to alloy with different metal additives. This thesis deals with the use liquid metals to synthesize liquid metal alloy catalysts to be utilized for carbon dioxide reduction through electrochemical processes. The additives used to synthesize liquid metal alloys were selected based on their ability to carry forward multi-electron reactions and solubility in the liquid metal mixture (EGaIn). Out of the five different additives, 3% vanadium in EGaIn (V-EGaIn) showed the best reducing performance in a simple electrochemical cell with dimethyl formamide electrolyte, based on current density that was double to the one reported in the past. Also, different electrolytes have been studied to reveal their effects on the controllability of products The last portion of the research consists of the formation of liquid metal droplets from the V-EGaIn and their immobilization of conductive surfaces to make electrodes for the reduction of carbon dioxide. The electrochemical activity increased due to the increased surface area of the catalyst thus providing more active sites for the electrochemical reaction to take place.