@article{bibcite_36748,
  author = {Xianhu Sun and Dongxiang Wu and Jianyu Wang and Shyam B Patel and Wenhui Zhu and Ji Yang and Timothy T Yang and Shuonan Ye and Xiaobo Chen and Yaguang Zhu and Linna Qiao and Meng Li and Stephen D House and Ji Su and Wissam A Saidi and Jorge Anibal Boscoboinik and Judith C Yang and Renu Sharma and Guangwen Zhou},
  title = {Oscillatory redox behavior in oxides: Cyclic surface reconstruction and reactivity modulation via the Mars{\textendash}van Krevelen mechanism},
  abstract = {<p>The breaking of translational symmetry at oxide surfaces gives rise to coordinatively unsaturated cations/anions and surface restructuring{\textemdash}key factors that govern surface reactivity. Using direct in situ environmental transmission electron microscopy (TEM) observations along with atomistic modeling, we report oscillatory redox behavior in CuO under H<sub>2</sub>, where cyclic surface reconstruction and reactivity modulation occur via the Mars{\textendash}van Krevelen (MvK) mechanism. We observe self-switching between oxygen-rich and oxygen-deficient surface reconstructions, alternately activating and deactivating the surface for H<sub>2</sub>O formation. During periods of chemical inactivity, the oxygen-deficient surface undergoes slow reoxidation via lattice oxygen diffusing from subsurface and bulk reservoirs, restoring the active oxygen-rich surface termination. The inherent disparity in chemical activity among undercoordinated surface ions, along with sluggish subsurface-to-surface oxygen replenishment, drives this oscillatory redox cycle, modulating H<sub>2</sub>-induced loss of lattice oxygen at the surface and its delayed replenishment from the subsurface. This creates spatiotemporally separated redox steps at the oxide surface. The phenomena and atomistic insights presented here have significant implications for manipulating the surface reactivity of oxides by tuning the separation of these redox steps.</p>},
  year = {2025},
  booktitle = {Proceedings of the National Academy of Sciences},
  journal = {Proceedings of the National Academy of Sciences},
  series = {Proceedings of the National Academy of Sciences},
  volume = {122},
  month = {17/06/2025},
  institution = {Proceedings of the National Academy of Sciences},
  publisher = {Proceedings of the National Academy of Sciences},
  issn = {0027-8424, 1091-6490},
  url = {https://doi.org/10.1073/pnas.2422711122},
  doi = {10.1073/pnas.2422711122},
}