Revealing the Dynamics of Oxygen Vacancy in ZnO_1-x/Cu during Robust Methanol Synthesis from CO₂

The extensive investigation regarding the active site of the Cu/ZnO/Al₂O₃ catalyst gradually recognizes the paramount importance of the oxygen vacancy in the hydrogenation of CO₂ to methanol. However, it is challenging to probe the nature of oxygen vacancy during methanol synthesis and understand its role in the enhancement of reactivity at the molecule level. Here, the inversed ZnO_1-x/Cu catalysts with abundant oxygen vacancies are prepared by simple ball milling. The interfacial transformations between ZnO_1-x and Cu during material preparation and reaction are elucidated by the correlations of geometrical and chemical states with mechanical energies. The dynamics of the oxygen vacancy during the reaction are revealed as well. The ZnO_1-x/Cu with more oxygen vacancy exhibits a superior CH₃OH productivity of 1.2 g_MeOH g^-1 h^-1 at 240 °C and a selectivity above 90%. The mechanistic studies reveal that oxygen vacancy promotes the activation of CO₂ to formate and significantly reduces the barrier of the hydrogenation from *HCOO to *H₂COO intermediates.