Abstract
Climate change and the global energy crisis have led to an increasing need for greenhouse gas remediation and clean energy sources. The electrochemical CO(2) reduction reaction (CO(2)RR) is a promising solution for both issues as it harvests waste CO(2) and chemically reduces it to more useful forms. However, the high overpotential required for the reaction makes it electrochemically unfavorable. Here, we fabricate a novel electrode composed of TiO(2) nanoparticles grown in situ on MXene charge acceptor 2D sheets with excellent CO(2)RR characteristics. A straightforward solvothermal method was used to grow the nanoparticles on the Ti(3)C(2)T(x) MXene flakes. The electrochemical performance of the TiO(2)/MXene electrodes was analyzed. The Faradaic efficiencies of the TiO(2)/MXene electrodes were determined, with a value of 99.41% at -1.9 V (vs. Ag/AgCl). Density functional theory mechanistic analysis was used to reveal the most likely mechanism resulting in the production of one CO molecule along with a carbonate anion through ∗CO, ∗O, and activated CO(2)(2-) intermediates. Bader charge analysis corroborated this pathway, showing that CO(2) gains a greater negative charge when TiO(2)/MXene serves as a catalyst compared to MXene or TiO(2) alone. These results show that TiO(2)/MXene nanocomposite electrodes may be very useful in the conversion of CO(2) while still being efficient in both time and cost.