Acetic Acid Production from CH₄ and CO₂ via Synergistic Catalysis between Pd Particles and Oxygen Vacancies Generated in ZrO₂

Co-conversion of CO2 and CH4 into acetic acid is of great significance to the environment but is challenged by their chemical stability. Herein, Pd–ZrO2 catalysts exhibit excellent performance for acetic acid production, which is about 5 times higher than that for pure ZrO2. Combined catalytic tests, characterization, and density functional theory (DFT) calculations have revealed a synergistic catalysis mechanism between Pd and H2-reduced ZrO2, which not only facilitates CO2 adsorption and activation owing to generating more oxygen vacancies (Ov) but also promotes CH4 activation owing to resulting larger-sized metallic Pd particles. DFT calculations demonstrate that the C–C coupling between CH3* and COOH* exhibits a lower barrier, which favors acetic acid formation.