Theoretical insights into the generation and reactivity of hydride on the ZnO(1010) surface.

ABSTRACT: ZnO is an important catalytic material for CO/CO₂ hydrogenation. In this work, the pristine ZnO(101̄0) and the surfaces with Zn-O dimer vacancies (ZnO(101̄0)-(Zn-O)_DiV) and oxygen vacancies are calculated. We find that the hydride (H^-) species can be generated via heterolytic H₂ dissociation on these surfaces, and that ZnO(101̄0)-(Zn-O)_DiV only needs to overcome the energy barrier of ∼0.10 eV. This is because the ZnO system has flexible orbitals for electron storage and release and the low-coordinated Zn_3c atoms at the defect sites can form stable Zn-H^- covalent bonds with high symmetry. Flexible Zn orbitals also impart the unique feature of activating multiple electrophilic adsorbates simultaneously as excess electrons exist. Moreover, we show that the covalent Zn-H^- species can regulate the catalytic activity and selectivity for CO₂ hydrogenation by preferentially producing *HCOO intermediates at Zn-O dimer vacancies. These results may help in the design of efficient Zn-based hydrogenation catalysts.

SUBMITTER: Zhang XY 

PROVIDER: S-EPMC11351784 | biostudies-literature | 2024 Aug

REPOSITORIES: biostudies-literature