THE INFLUENCE OF AUXILIARY ELECTRODE TYPES IN ELECTROCHEMICAL CO2 REDUCTION REACTOR

• Main Author: Martona Ardian, Yosua
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/81845
• Institution: Institut Teknologi Bandung

Indonesia energy needs still depends heavily on fossil fuels, which produce high CO2 emissions. Converting CO2 into formic acid, an added value product, through CO2 electrochemical reduction becomes crucial. Formic acid yield and current efficiency are influenced by anodic reactions. Further review is needed on the use of anodes that can produce formic acid economically. Anode variation types for CO2 electroreduction comprise different shapes and sizes of stainless steel, carbon, and titanium. Cathode, catholyte, and anolyte used are Pb-Sn, KHCO3, and KOH, respectively. Stainless steel and titanium shape variations are mesh and plate with cross-sectional areas of 3 x 3 cm² and 2 x 2 cm². Furthermore, carbon form shape variations are cloth and plate 3 x 3 cm². Chemically-activated carbon is also tested. Each type of anode is tested with H2SO4 as the anolyte. Anode morphology characterization is performed using SEM and formic acid is analyzed using HPLC. The result show that anode material affects the formic acid yield based on electrical conductivity. The SS-Ti anode influences the formic acid yield and current efficiency through surface area and LHSV, while the carbon anode only through the surface area. Carbon material activation can enhance its electrical conductivity. Surface area and electrical conductivity are directly proportional to circulating current, whereas LHSV is inversely proportional to current. Higher electric current increases formic acid yield. Acidic anolyte environment can lead to higher metal corrosion rates, formic acid yields, and current efficiencies compared to alkaline environment. The highest formic acid yield and current efficiency in acidic anolyte are achieved using activated carbon cloth anode, with values of 22.6 mg and 3.44%, respectively. In alkaline anolyte, the highest values are obtained using SS 316 mesh anode, with values 3.3 mg and 0.33%, respectively, during a 3-hour CO2 electroreduction process before the CO2 diffuser replacement.