Facet-dependent acidic and catalytic properties of sulfated titania solid superacids

Abstract

Sulfated titania solid superacids with dominant {001}, {001}/{101}, and {101} facets were prepared by the hydrothermal method and subsequent sulfation. Their facet-dependent acidic properties were investigated by the solid-state (31)P NMR technique and Pechmann condensation of 5,7-dihydroxy-4-methyl coumarin.

Study of Oxygen Vacancies on Different Facets of Anatase TiO2

“…The broadening of the peaks indexed to (004) facets in T001 and T101/001 diffraction patterns is ascribed to the decrease of crystallite size in the direction perpendicular to {001} facets. In addition, the narrowing of peaks attributed to (200) facets in T001 is caused by the increase of the crystallite size in the direction perpendicular to {100} facets, and this is in good accordance with the shape of T001 samples as nanosheets shown in Figure a . Compared with T001 and T101/001 samples, the broadening of the peak indexed to (101) facets indicates the decrease of crystallite size in the direction perpendicular to {101} facets in T101 sample.…”

“…10 nm. The percentage of {001} facets is estimated to be less than 10% on T101 samples [17a]. The lattice fringes with d‐spacings of 0.24, 0.19 and 0.35 nm are in accordance with (004), (200) and (101) planes of anatase TiO 2 , respectively, as found in Figure f.…”

“…Anatase TiO 2 samples with different exposed facets were prepared by hydrothermal synthesis [17a]. In a typical process, 5 mL of tetrabutyltitanate and a certain amount of hydrofluoric acid (40—48 wt%) was added dropwise into a Teflon‐lined autoclave with a capacity of 50 mL.…”

A Highly Active, Readily Synthesized and Easily Separated Graphene Oxide (GO)/Polyethersulfone (PES) Catalytic Membrane for Biodiesel Production

“…Many SACs, such as solid superacids, strong acidic cation‐exchange resin and −SO 3 H‐functionalized carbon materials have been synthesized and used in acid‐catalyzed reactions . Among all these catalysts mentioned above, carbon‐based solid acid catalysts (CBSACs) with outstanding hydrothermal, mechanical and catalytic properties have received numerous attentions recently .…”

The Effects of Exposed Specific Facets and Sulfation on the Surface Acidity of Cu2O Solids

“…However,i ti sr are to see the studyo nt he acidic properties after sulfationo fm etal oxidesw ith specific exposed facets.I n the previous research we reported sulfated TiO 2 solid superacids and found their acidic and catalytic properties are facetdependent. [10] In this work, three different Cu 2 Om icrocrystals with various morphologies were preparedi ncluding octahedra with dominant {111}f acets, cuboctahedra with both {100} and {111} facets, and cubes with dominant {100} facets. These Cu 2 Os amples were sulfated and 31 PMAS NMR was used to study their acid properties with trimethylphosphine (TMP) as the probe molecule.…”