Enhancement of the Catalytic Effect on the Electrochemical Conversion of CO₂ to Formic Acid Using MXene (Ti₃C₂T_x)-Modified Boron-Doped Diamond Electrode

The rising concentration of carbon dioxide (CO₂) as one of the greenhouse gases in the atmosphere is a major source of worry. Electrochemical reduction of CO₂ is one of many ways to convert CO₂ gas into usable compounds. An electrochemical technique was applied in this study to reduce CO₂ using a boron-doped diamond (BDD) working electrode modified with MXene (Ti₃C₂T_x) material to improve electrode performance. MXene concentrations of 0.5 mg/mL (MXene-BDD 0.5), 1.0 mg/mL (MXene-BDD 1.0), and 2.0 mg/mL (MXene-BDD 2.0) were drop-casted onto the BDD surface. MXene was effectively deposited on top of the BDD surface, with Ti weight loads of 0.12%, 4.06%, and 7.14% on MXene-BDD 0.5, MXene-BDD 1.0, and MXene-BDD 2.0, respectively. The modified working electrode was employed for CO₂ electroreduction with optimal CO₂ gas aeration. The existence of the MXene substance in BDD reduced the electroreduction overpotential of CO₂. For the final result, we found that the MXene-BDD 2.0 electrode effectively generated the most formic acid product with a maximum reduction potential as low as −1.3 V (vs. Ag/AgCl).