Catalytic properties of trivalent rare-earth oxides with intrinsic surface oxygen vacancy.

Xu, Kai; Liu, Jin-Cheng; Wang, Wei-Wei; Zhou, Lu-Lu; Ma, Chao; Guan, Xuze; Wang, Feng Ryan; Li, Jun et al. · Nat Commun · 2024

basic_science · Level V

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Abstract

Oxygen vacancy (O<sub>v</sub>) is an anionic defect widely existed in metal oxide lattice, as exemplified by CeO<sub>2</sub>, TiO<sub>2</sub>, and ZnO. As O<sub>v</sub> can modify the band structure of solid, it improves the physicochemical properties such as the semiconducting performance and catalytic behaviours. We report here a new type of O<sub>v</sub> as an intrinsic part of a perfect crystalline surface. Such non-defect O<sub>v</sub> stems from the irregular hexagonal sawtooth-shaped structure in the (111) plane of trivalent rare earth oxides (RE<sub>2</sub>O<sub>3</sub>). The materials with such intrinsic O<sub>v</sub> structure exhibit excellent performance in ammonia decomposition reaction with surface Ru active sites. Extremely high H<sub>2</sub> formation rate has been achieved at ~1 wt% of Ru loading over Sm<sub>2</sub>O<sub>3</sub>, Y<sub>2</sub>O<sub>3</sub> and Gd<sub>2</sub>O<sub>3</sub> surface, which is 1.5-20 times higher than reported values in the literature. The discovery of intrinsic O<sub>v</sub> suggests great potentials of applying RE oxides in heterogeneous catalysis and surface chemistry.