The pivotal role of oxygen vacancy and surface hydroxyl in the adsorption and activation of CO 2 on ceria-zirconia mixed oxide

Ceria-zirconia mixed metal oxide along with pure ceria and zirconia were prepared by the co-precipitation method and characterized by N 2 -Physisorption, X-ray diffraction (XRD), H 2 -temperature programmed reduction (H 2 -TPR), CO-TPR with mass spectroscopy (CO-TPR/MS), oxygen storage capacity (OSC), CO and CO 2 -temperature programmed desorption with MS (TPD/MS), Raman spectroscopy, XPS, and diffuse reflectance infrared Fourier transform Spectroscopy (DRIFTS) techniques. Furthermore, Density Functional Theory (DFT) calculations were performed to acquire molecular insights into the role of oxygen vacancies and surface hydroxyl species in CO 2 adsorption and subsequent activation. Our experimental and theoretical results corroborated the fact that the incorporation of zirconium ions into the ceria matrix enhanced the overall CO 2 adsorption and activation by forming thermally stable surface species, which were eventually detected by DRIFTS. Additionally, DFT calculations revealed the oxygen vacancy mediated change in the electronic structure of ceria-zirconia mixed oxide, which had been argued to improve its catalytic activity. Furthermore, the oxygen vacancy formation energy (OVFE), oxygen storage capacity (OSC) and CO 2 adsorption energies were correlated to augment the importance of these properties.