The rising concentration of carbon dioxide (COsub.2) as one of the greenhouse gases in the atmosphere is a major source of worry. Electrochemical reduction of COsub.2 is one of many ways to convert COsub.2 gas into usable compounds. An electrochemical technique was applied in this study to reduce COsub.2 using a boron-doped diamond (BDD) working electrode modified with MXene (Tisub.3Csub.2Tsub.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 COsub.2 electroreduction with optimal COsub.2 gas aeration. The existence of the MXene substance in BDD reduced the electroreduction overpotential of COsub.2. 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).