Generalized Synthetic Strategy for Transition-Metal-Doped Brookite-Phase TiO₂ Nanorods

Abstract

We report a generalized wet-chemical methodology for the synthesis of transition-metal (M)-doped brookite-phase TiO2 nanorods (NRs) with unprecedented wide-range tunability in dopant composition (M = V, Cr, Mn, Fe, Co, Ni, Cu, Mo, etc.). These quadrangular NRs can selectively expose {210} surface facets, which is induced by their strong affinity for oleyl­amine stabilizer. This structure is well preserved with variable dopant compositions and concentrations, leading to a diverse library of TiO2 NRs wherein the dopants in single-atom form are homogeneously distributed in a brookite-phase solid lattice. This synthetic method allows tuning of dopant-dependent properties of TiO2 nanomaterials for new opportunities in catalysis applications.

Smectic Liquid Crystalline Titanium Dioxide Nanorods: Reducing Attractions by Optimizing Ligand Density

“…[1][2][3][4][5] Liquid crystals (LCs) formed by inorganic anisotropic particles demonstrate tunable optical characteristics that are of paper: Nanocrystals (NCs) have generally different facets with different surface tensions and thus different densities of ligands generally which has been shown to affect the SA behavior of the NPs. [29][30][31][32]42] For instance, in ref. [31] the differences in the density of the ligands on different facets of the plate-shaped NPs was determined by density functional calculations by the Glotzer group and the differences that this caused in the interactions between the particles was found to be essential in subsequent simulations of the SA process to explain the colloidal crystal phases as observed by the Murray group.…”

“…[32] Excess ligands, even if added after completion of the SA, were also found to be able to affect interparticle spacings and the order in colloidal crystals already formed. [36] It is often the case that ligands are not bound covalently to the surface and thus can be replaced or removed by frequent washing steps [35,[42][43][44][45] and conversely that the presence of excess ligands affects SA. [36,46] Additionally, addition of excess ligands above the critical micelle concentration can cause the formation of micelles which can induce depletion attractions between the NPs.…”

Diffusion doping of cobalt in rod-shape anatase TiO2 nanocrystals leads to antiferromagnetism

“…A number of reports of cobalt doping in TiO 2 nanomaterials do not include steps for removal of unbound or surface metal atoms such that the subsequent characterization and analyses may not correlate exclusively to cobalt-doped TiO 2 . [39][40][41] The Co (doped) -TiO 2 nanocrystals were characterized with TEM and XRD methods ( Fig. 3 and S2 †).…”

Structure, Morphology, and Faceting of TiO2 Photocatalysts by the Debye Scattering Equation Method. The P25 and P90 Cases of Study

“…The functionality of crystalline nanomaterials, and particularly of those possessing anisotropic shapes (as a consequence of low(er) symmetry structures or synthesis conditions), is heavily dependent on the surface extension and on the type of exposed crystal faces [1]. This widely encompasses, to mention a few, chemical reactivity, catalysis, rheology, luminescence, and photocatalytic activity [2,3].…”

“…Simulated X-ray scattering patterns for anatase nanocrystals (NCs) having truncated bipyramidal shapes, (a) with different aspect ratios, AR, at constant volume (1300 nm3 ) and (b) with different volumes at constant AR = 0.5 and AR = 1.5. Simulations in (a) are on the absolute scale, whereas in (b) scaling was applied to facilitate the comparison of nanocrystals with different volumes.…”