In this work, the synthesis and physiochemical characterization of titanium oxide nanoparticle-graphene oxide (TiO 2 -GO) and titanium oxide nanoparticle-reduced graphene oxide (TiO 2 -RGO) composites was undertaken. TiO 2 -GO materials were prepared via the hydrolysis of TiF 4 at 60 °C for 24 h in the presence of an aqueous dispersion of graphene oxide (GO). The reaction proceeded to yield an insoluble material that is composed of TiO 2 and GO. Composites were characterized by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), Raman spectroscopy, N 2 adsorption-desorption, and thermal gravimetric analysis/differential thermal analysis (TGA/DTA). This approach yielded highly faceted anatase nanocrystals with petal-like morphologies on and embedded between the graphene sheets. At higher GO concentrations with no stirring of the reaction media, a long-range ordered assembly for TiO 2 -GO sheets was observed due to self-assembly. GO-TiO 2 composites formed colloidal dispersions at low concentrations (∼0.75 mg/mL) in water and ethanol but were not amenable to forming graphene papers via filtration through Anodisc membranes (0.2 µM pore diameter) due to their high titania concentration. Zeta potential measurements and particle size distributions from dynamic light scattering (DLS) experiments on these materials explain the stability of the TiO 2 -GO colloidal solutions. Chemical and thermal methods were also used to reduce TiO 2 -GO to give TiO 2 -RGO materials.

Here we report on the application of sol-gel template synthesis to the investigation of size-induced ferroelectric phase transitions in lead titanate (PbTiO 3 ) nanotubes and nanofibers. A 0.8 M chelate solgel, made from titanium(IV) tertabutoxide and lead(II) trihydrate acetate, was applied to two different templates. Nanotubes were formed within 200-nm-pore Whatman anodisc aluminum oxide membranes, and nanofibers were prepared using 50-, 100-, and 200-nm Whatman track-etched polycarbonate membranes. Transmission electron microscopy images revealed that the tubes comprised grains of e20 nm and the fibers comprised individual grains e200 nm in width when a 200-nm pore size template is used. An examination of how the grain/crystallite size and aspect ratio of one-dimensional morphologies affect the ferroelectric phase transition was monitored through the comparison of bulk powders and the nanostructured materials using electron diffraction, X-ray diffraction, Raman spectroscopy, and differential scanning calorimetry.

Select members of a series of structurally characterized calcium aryloxides (Ca(OAr)2) were found to influence the morphologies and phases of the final calcium ceramic nanomaterials produced, independent of the process route investigated. The Ca(OAr)2 were synthesized using an amide alcohol exchange route between [Ca(μ-NR2)(NR2)]2 (R = Si(CH3)3) and the appropriate aryl alcohol [H-OAr = H-OC6H4(R)-2 where R = CH(CH3)2 (H-oPP), C(CH3)3 (H-oBP); H-OC6H3(R)2-2,6 where R = CH3 (H-DMP), CH(CH3)2 (H-DIP), and C(CH3)3 (H-DBP)] along with triphenyl silanol (H-TPS = OSi(C6H5)3], in toluene (tol) or tetrahydrofuran (THF). The resulting products were isolated as H+[(μ3-O)Ca2(μ-oPP)2(oPP)(THF)3]2·THF]- (1), Ca(oBP)2(THF)4 (2), H+[(μ3-O)Ca2(μ-DMP)2(DMP)(THF)3]2 - (3), {2[Ca(DIP)2(THF)3]·Ca(DIP)2(THF)4}·THF (4a), [Ca(μ-DIP)(DIP)(THF)2]2 (4b), Ca(DBP)2(THF)3 (5), [Ca(μ-DBP)(DBP)]2 (6), and Ca(TPS)2(THF)4 (7). The coordination of the Ca atoms ranged from trigonal planar to octahedral, forming mono-, di-, and tetranuclear species based on the steric bulk of the ligand and coordination of Lewis basic THF. Solution NMR indicated that these compounds retain their structure in solution, except for 5, which was found to be disrupted to form a monomer. Vaterite or portlandite nanomaterials were isolated from 3 or 4a, respectively, independent of the processing route (solvothermal or solution precipitation). The morphology variations were interpreted based on the “precursor structure argument”, and the phase variation was attributed to the “precursor's decomposition pathway”. Full details of the synthesis and characterization of 1−7 as well as the nanomaterials generated therefrom are discussed.

For the first time tungsten based nanoparticles (WNPs) of scheelite (MWO 4 ; M = Ca, Sr, Ba, Pb), wolframite (MWO 4 (9) where Mes = C 6 H 2 (CH 3 ) 3 -2,4,6, ONep = OCH 2 CMe 3 , Et = CH 2 CH 3 , and py = pyridine. Through these routes, the WNP morphologies were found to be manipulated by the processing conditions, while precursor selection influenced the final phase observed. For the solution precipitation route, 1 yielded (5 × 100 nm) W 18 O 49 rods while stochiometeric reactions between 1 and (2 -9) generated homogenous sub 30 nm nano-dots, -diamonds, -rods, and -wires for the MWO 4 systems. For the solvothermal route, 1 was found to produce wires of WO 3 with aspect ratios of 20 while (1 & 2) formed 10 -60 nm CaWO 4 nanodots. Room temperature photoluminescent (PL) emission properties of select WNPs were also examined with fluorescence spectroscopy (λ ex = 320 nm). Broad PL emissions = 430, 420, 395, 420 nm were;