Facile formation of barium titanium oxyhydride on a titanium hydride surface as an ammonia synthesis catalyst.

ABSTRACT: Oxyhydrides are promising compounds as supports for ammonia synthesis catalysts because they suppress hydrogen poisoning on the catalyst surface and enhance the ammonia synthesis activity. Herein, we developed a facile method for preparing BaTiO_2.5H_0.5, a perovskite oxyhydride, on a TiH₂ surface via the conventional wet impregnation method using TiH₂ and Ba hydroxide. Scanning electron microscopy and high-angle annular dark-field scanning transmission electron microscopy observations revealed that BaTiO_2.5H_0.5 crystallized as nanoparticles of ca. 100-200 nm on the TiH₂ surface. The Ru-loaded catalyst Ru/BaTiO_2.5H_0.5-TiH₂ exhibited 2.46 times higher ammonia synthesis activity (3.05 mmol-NH₃ g^-1 h^-1 at 400 °C) than the benchmark Ru catalyst Ru-Cs/MgO (1.24 mmol-NH₃ g^-1 h^-1 at 400 °C) because of the suppression of hydrogen poisoning. The analysis of reaction orders showed that the effect of suppressing hydrogen poisoning on Ru/BaTiO_2.5H_0.5-TiH₂ was equivalent to that of the reported Ru/BaTiO_2.5H_0.5 catalyst, thus supporting the formation of BaTiO_2.5H_0.5 perovskite oxyhydride. This study demonstrated that the selection of appropriate raw materials facilitates the formation of BaTiO_2.5H_0.5 oxyhydride nanoparticles on the TiH₂ surface using the conventional synthesis method.

SUBMITTER: Goto Y 

PROVIDER: S-EPMC10201397 | biostudies-literature | 2023 May

REPOSITORIES: biostudies-literature