Extended Data Fig. 4: Atomically dispersed La on mesoporous zeolite with silanol nests.
From: Rare-earth–platinum alloy nanoparticles in mesoporous zeolite for catalysis
a, FT-IR spectra of mz, mz-deGa and mz-Ga. The mz-Ga sample shows the FT-IR absorbance band corresponding to isolated Si–OH (about 3,750 cm−1) and Ga–OH (3,600 cm−1). The mz-deGa sample displays increased broad FT-IR adsorption at around 3,500 cm−1, which is assigned to the silanol nests. The mz sample shows one sharp FT-IR peak corresponding to the isolated silanols. b, HAADF-STEM image of LaOx-supported mz-deGa showing no noticeable white dots on the grey zeolite matrix, which can be regarded as LaOx nanoparticles. c, AR-HAADF-STEM image of LaOx/mz-deGa magnified from the STEM image of b, revealing the single-atom-dispersed La species as white dots. d, HAADF-STEM image of LaOx-supported mz, showing the nanoparticle-like LaOx species as white dots. As shown in the HAADF-STEM images and FT-IR spectra, La species can be single-atom-dispersed only if the mesoporous MFI zeolite has sufficient silanol nests. e, FT-IR spectra of La-supported mz-deGa samples with various La loadings. The samples were prepared by incipient wetness impregnation of La nitrate and subsequent heat treatment at 350 °C under an O2 flow. The absorption band corresponding to the silanol nest (~3,500 cm−1; marked with an arrow) was gradually weakened with increasing La loading, indicating that the incorporated La species resulted in the formation of bonds with the silanol nests present in the mz-deGa support.
