Non-hydrolytic Sol Gel Route Research Articles

Low-temperature preparation of nano-sized Al2TiO5 powder via non-hydrolytic sol-gel route with Al metal as the aluminum source

Al2TiO5 powder was prepared using the non-hydrolytic sol-gel route, with Al powder and titanium tetrachloride as precursor materials. The synthesized powder was characterized via XRD, DSC-TG, TEM, FTIR, FE-SEM, and laser particle size analyzer. The results indicated that Al2TiO5 powder can be synthesized at 750 ℃ via gelation when the aluminum-to-alcohol molar ratio was 1:14 and titanium tetrachloride concentration was 0.9 mol/L. The average particle size of Al2TiO5 powder was 80 nm using reflux gelation and 35 nm with direct drying gelation. The Al metal utilized the hydrogen chloride produced in situ to activate itself and formed Al-O-Ti hetero-bonds through non-hydrolytic polycondensation. The Al-O-Ti hetero-bonds underwent an exothermic reaction at around 695 ℃ to form Al2TiO5. This research has broadened the range of precursor materials available for preparing Al2TiO5 using the non-hydrolytic sol-gel route.

Photocatalytic Degradation of Paracetamol and Antibacterial Activity of La-Modified TiO2 Obtained by Non-Hydrolytic Sol–Gel Route

The current study aims to synthesize and analyze both pure and La-doped TiO2, and evaluate the photocatalytic and antibacterial activity of as-prepared samples. Doped and undoped samples were prepared by the non-hydrolytic sol–gel method from titanium(IV) chloride, benzyl alcohol, and lanthanum(III) nitrate followed by thermal treatment. Lanthanum content in synthesized samples was 0.4, 1, and 5 mol%. The resulting nanopowders’ structure and morphology were described using XRD, IR, and UV–Vis analysis. The average particle sizes of pure and doped TiO2 were about 6–15 nm and anatase was found to be a dominant crystalline phase in the samples. It was observed that particle sizes decreased on increasing La content. The photocatalytic activity of the pure and La-doped sol–gel powders was estimated in the decomposition of paracetamol in distilled water using ultraviolet light illumination. Doping with lanthanum ions has been shown to increase the photocatalytic properties on the degradation of paracetamol. Furthermore, the annealed catalysts (pure and La3+ doped) showed increased photocatalytic activity and degradation of the analgesic in comparison with non-annealed materials. In both cases, the highest photocatalytic efficiency is observed at the optimal La3+ (1 mol%) concentration. The antimicrobial activity of 1 mol% La/TiO2 was tested against a reference strain E. coli in the presence of ultraviolet light and in dark conditions. The number of viable bacterial cells was determined by a spread plate method, and kill curves were performed. The results showed that photoactivated 1 mol% La/TiO2 exhibited a strong bactericidal effect, and in concentration, 1 mg/mL efficiently killed bacteria at an initial cell density of about 105 colony forming units in 1 mL within 15 min.

Solids containing Si-O-P bonds: is the hydrolytic sol-gel route a suitable synthesis strategy?

AbstractMaterials based on silicon-phosphorus mixed oxides have traditionally attracted interest in electronics, optics, catalysis, and related fields. The preparation of a solid containing stable Si–O–P linkages is a huge challenge due to their intrinsic instability to hydrolysis in a wet atmosphere. On the other hand, most technological applications of these materials, such as protonic conductive membranes in fuel cells and water-tolerant solid acid catalysts, are related to their interaction with water; consequently, suitable synthesis procedures that positively face this tradeoff are mandatory. Besides the traditional high-temperature techniques, sol-gel synthetic methods represent a viable, low-cost alternative, allowing for the preparation of high-purity materials with a homogeneous distribution of the components at the atomic scale. Si–O–P linkages are easily obtained by nonhydrolytic sol-gel routes, but only in inert and dry atmosphere. Conversely, hydrolytic routes offer opportunities to control the structure of the products in a wide range of processing conditions. The present review aims at providing an overall picture of the research on the sol-gel synthesis of phosphosilicate and related materials and theisr different applications, emphasizing how the interest in these systems is still lively, considering both conventional and emerging applications, such as flame retardance. The incorporation of Si–O–P nanostructures in polymer composites, coatings, and textiles is indeed a promising strategy to improve properties like thermal stability and fire resistance; however, their in-situ synthesis brings about additional difficulties related to the reactivity of the precursors. The perspectives linked with the development of Si–P-based materials are finally outlined. Graphical Abstract

Non-hydrolytic Sol–Gel Routes to Bifunctional Cu–Ta–SiO2 Catalysts for the Upgrading of Ethanol to Butadiene

Non-hydrolytic Sol–Gel Routes to Bifunctional Cu–Ta–SiO₂ Catalysts for the Upgrading of Ethanol to Butadiene

A Non-Hydrolytic Sol–Gel Route to Organic-Inorganic Hybrid Polymers: Linearly Expanded Silica and Silsesquioxanes

Condensation reactions of chlorosilanes (SiCl4 and CH3SiCl3) and bis(trimethylsilyl)ethers of rigid, quasi-linear diols (CH3)3SiO-AR-OSi(CH3)3 (AR = 4,4'-biphenylene (1) and 2,6-naphthylene (2)), with release of (CH3)3SiCl as a volatile byproduct, afforded novel hybrid materials that feature Si-O-C bridges. The precursors 1 and 2 were characterized using FTIR and multinuclear (1H, 13C, 29Si) NMR spectroscopy as well as single-crystal X-ray diffraction analysis in case of 2. Pyridine-catalyzed and non-catalyzed transformations were performed in THF at room temperature and at 60 °C. In most cases, soluble oligomers were obtained. The progress of these transsilylations was monitored in solution with 29Si NMR spectroscopy. Pyridine-catalyzed reactions with CH3SiCl3 proceeded until complete substitution of all chlorine atoms; however, no gelation or precipitation was found. In case of pyridine-catalyzed reactions of 1 and 2 with SiCl4, a Sol-Gel transition was observed. Ageing and syneresis yielded xerogels 1A and 2A, which exhibited large linear shrinkage of 57-59% and consequently low BET surface area of 10 m2⋅g-1. The xerogels were analyzed using powder-XRD, solid state 29Si NMR and FTIR spectroscopy, SEM/EDX, elemental analysis, and thermal gravimetric analysis. The SiCl4-derived amorphous xerogels consist of hydrolytically sensitive three-dimensional networks of SiO4-units linked by the arylene groups. The non-hydrolytic approach to hybrid materials may be applied to other silylated precursors, if the reactivity of the corresponding chlorine compound is sufficient.

In situ synthesis of titanium phosphonate by a non-hydrolytic sol-gel route within a viscous polymer medium

In situ synthesis of titanium phosphonate by a non-hydrolytic sol-gel route within a viscous polymer medium

Nonhydrolytic sol-gel in-situ synthesis of high performance MgAl2O4/C adsorbent materials

MgAl2O4/C composite was prepared via a facile low-temperature non-hydrolytic sol-gel (NHSG) route, using Mg powder, Al wire and isopropanol as raw materials. The influence of types of magnesium source and heat treatment temperature on the synthesis and adsorption properties were investigated, and the adsorption mechanism was also studied. The results showed that the amorphous MgAl2O4 formed at < 600 °C, and it crystallized at 700 °C. No impurity phase appeared in the samples calcined at 700–1300 °C, which was attributed to MgAl2O4 crystallized directly from Mg(Al(OiPr)4)2. The uniform-doped carbon in MgAl2O4/C composites came in-situ from the organic groups in Mg(Al(OiPr)4)2. MgAl2O4/C showed a superior adsorption capacity for Congo red (CR). The bimetallic alkoxides structure was favorable for high adsorption property, and the adsorption property of amorphous MgAl2O4/C was significantly superior to that of its crystalline counterpart. The adsorption kinetics data was fitted with the pseudo-second-order model, while the Langmuir isotherm model could well descript the adsorption isotherm behavior, and the maximum adsorption capacity for CR was 5690 mg/g. The high adsorption capacity was attributed to the Lewis acid-base reaction and the electrostatic interactions between the anionic dye CR and MgAl2O4/C surface as well as the in-situ carbon, and amorphous state.

Polymer and biopolymer organic-inorganic composites containing mixed oxides for application in energy up- and down-conversion

Organic-inorganic composites are interesting for many commercial applications— the chemical and thermal stability of inorganic oxides combined with the processability and flexibility of organic compounds and polymers provides these composites with attractive mechanical, optical, and thermal properties. In general, the desired properties cannot be found in one single constituent, but adequate association of the components affords composites with complementary properties. In this study, we have synthesized and characterized organic-inorganic composites based on the natural polymers Gellan Gum and Karaya Gum containing luminophores consisting of niobium and gadolinium mixed oxides doped with Eu3+ or Yb3+/Er3+. In this paper luminophores were prepared by a modified non-hydrolytic sol-gel route, and was obtained the organic-inorganic composites by the casting technique. The investigated how the luminophore concentration, 1.0 or 3.0% m/m of gum, affected the luminescent properties of the composites. For all the composites doped with Eu3+, the down-shifting luminescence results revealed an intense emission band at 612 nm, due to the 5D0 → 7F2 transition of Eu3+, as well as an emission band between 300 and 500 nm, attributed to polymer emission, which shifted the chromaticity coordinates toward the blue region. As for the composites doped with Yb3+/Er3+, they displayed bands at 1005 and 1535 nm, ascribed to the 2F5/2 → 2F7/2 and 4I13/2 → 4I15/2 transitions of Yb3+ and Er3+, respectively. The up-conversion luminescence results evidenced emission bands in the visible region, at 520, 550, and 655 nm, assigned to the 2H11/2 → 4I15/2, 4S3/2 → 4I15/2, and 4F9/2 → 4I15/2 transitions of Er3+, respectively, indicating that two photons were absorbed.

Photodegradation of Fipronil by Zn-AlPO4 Materials Synthesized by Non-Hydrolytic Sol–Gel Method

In recent decades, the increasing use of pesticides to improve food productivity has led to the release of effluents that contaminate the environment. To prepare a material that may help to treat effluents generated during agricultural practice, we used a new method based on the non-hydrolytic sol-gel route to obtain zinc photocatalysts in aluminophosphate matrixes. IR spectroscopy, X-ray diffraction, thermal analysis, differential scanning electron microscopy, energy dispersion spectroscopy, and specific surface area and pore volume determined from the nitrogen adsorbed were used to characterize materials treated at different temperatures. X-ray analysis showed how heat-treatment affected the structure of the material: Zn-AlPO4 in the trigonal and orthorhombic phase was obtained at 750 and 1000 °C, respectively. These phases directly influenced the ability of the material to generate OH radicals. The capacity of the materials to treat effluents was tested in the photodegradation of the pesticide Fipronil. The photocatalytic reactions were monitored by ultraviolet-visible spectroscopy and gas chromatography-mass spectrometry analyses. Zn-AlPO4 treated at 750 °C showed better photodegradation results--it removed 80% of the pesticide in 2 h when higher mass (150 mg) was tested. Long-time treatment of the effluent with Zn-AlPO4 treated at 750 °C completely photodegraded Fipronil. GC-MS analysis confirmed the photodegration profile, and only traces of Fipronil were observed after photocatalytic reaction for 120 min in the presence of Zn-AlPO4 treated at 750 °C under UV radiation.

Synergetic effect of oxygen vacancies and morphology of ZnO photocatalyst prepared by non-hydrolytic sol-gel route for the photo-oxidation of 2-propanol in a gas-solid system

The effects of the nature of some carboxylic acids (oxalic, malic, citric, and tartaric acid) and of the annealing temperature in the preparation of the ZnO photocatalyst by a non-hydrolytic sol-gel route (using zinc acetate as the precursor) have been studied for oxidation of 2-propanol in air as probe reaction in a gas-solid regime. The physico-chemical characterization by XRD, SEM/EDX and UV–vis-DRS revealed a synergetic effect of the presence of oxygen vacancies and morphology of ZnO on the reaction performance. Oxygen vacancies were found to increase with decreasing annealing temperature, and this result indicates the possibility of their production in situ without the addition of a doping agent.XRD results showed that ZnO samples present a pure wurtzite structure with an average crystal size ranging from 21 nm to 42 nm. The specific surface area of samples ranged from 3.0 m2·g–1 to 18 m2·g–1and SEM observation indicated the presence of different agglomeration of both faceted and non-faceted particles. The lowest band gap energy of ZnO was 3.2 eV. The photocatalytic oxidation of 2-propanol in gas-solid regime was carried out in oxygen atmosphere. An increase of acid concentration during the ZnO preparation caused a decrease on the activity of the photocatalyts. An increasing amount of zinc acetate with respect to acid during the preparation of the photocatalysts enhanced the oxygen vacancies in the solid, which induced an increase of the 2-propanol oxidation rate constant. The increasing of the annealing temperature decreased the oxygen vacancies and hence the photocatalytic activity of ZnO. The highest 2-propanol oxidation rate (kapp = 4.00·10–2 min–1) was obtained by using the ZnO sample prepared with a 1:2 molar ratio of zinc acetate:oxalic acid, and annealed at 400 °C. This photocatalyst showed an oxidation rate 80 times higher than that of the least active photocatalyst (kapp = 5.00·10–4 min–1) obtained using zinc acetate:tartaric acid at 1:1 molar ratio and annealed at 500 °C.

A hybrid solid electrolyte for high-energy solid-state sodium metal batteries

Exploring solid electrolytes with promising electrical properties and desirable compatibility toward electrodes for safe and high-energy sodium metal batteries remains a challenge. In this work, these issues are addressed via an in situ hybrid strategy, viz., highly conductive and thermally stable 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide is immobilized in nanoscale silica skeletons to form ionogel via a non-hydrolytic sol-gel route, followed by hybridizing with polymeric poly(ethylene oxide) and inorganic conductor Na3Zr2Si2PO12. Such hybrid design yields the required solid electrolyte, which shows not only a stable electrochemical stability window of 5.4 V vs Na/Na+ but also an extremely high ionic conductivity of 1.5 × 10−3 S cm−1 at 25 °C, which is demonstrated with the interacted and monolithic structure of the electrolyte by SEM, XRD, thermogravimetric (TG), and XPS. Moreover, the capabilities of suppressing sodium metal dendrite growth and enabling high-voltage cathode Mg-doped P2-type Na0.67Ni0.33Mn0.67O2 are verified. This work demonstrates the potential to explore the required solid electrolytes by hybridizing an in situ ionogel, a polymer, and an inorganic conductor for safe and high-energy solid-state sodium metal batteries.

Tuning Polymer/TiO2 Nanocomposites Morphology by In Situ Non-Hydrolytic Sol-Gel Syntheses in Viscous Polymer Medium: Influence of the Polymer Nature and Oxygen Donor.

Herein, we reported the synthesis of TiO2 through different non-hydrolytic sol-gel (NHSG) routes in viscous polymer media. For the first time, the influence of the polymer nature (Polystyrene (PS) or Polypropylene (PP)) on the morphology of synthesized inorganic domains was investigated. The non-hydrolytic sol-gel reactions between titanium isopropoxide Ti(OiPr)4 and acetic anhydride in molten polypropylene lead to the formation of microfillers with a mean diameter of about 1 μm, while the same synthesis carried out in viscous polystyrene lead to the formation of nanofillers with diameter lower than 10 nm forming aggregates of approximately 200 nm. We have also investigated the influence of the oxygen donor nature on the morphology of synthesized fillers using aromatic oxygen donors in a polystyrene matrix. The use of benzoic anhydride or acetophenone as oxygen donors with Ti(OiPr)4 in viscous polystyrene lead to respectively platelet-like morphology or aggregated nanofillers. We demonstrated that the affinity between polymer, reactants, and/or by-products had an influence on the morphology and the size of in situ synthesized TiO2 fillers. These results evidenced for the first time the possibility to control and to tune the morphology of in situ grown inorganic objects through the NHSG process by the appropriate choice of solvent, here a viscous polymer medium, and reactants.

Synthesis and Characterization of Anatase TiO2 Nanorods: Insights from Nanorods’ Formation and Self-Assembly

Highly crystalline, organic-solvent-dispersible titanium dioxide (TiO2) nanorods (NRs) present promising chemicophysical properties in many diverse applications. In this paper, based on a modified procedure from literature, TiO2 NRs were synthesized via a ligand-assisted nonhydrolytic sol-gel route using oleic acid as the solvent, reagent, and ligand and titanium (IV) isopropoxide as the titanium precursor. This procedure produced monodisperse TiO2 NRs, as well as some semi-spherical titania nanocrystals (NCs) that could be removed by size-selective precipitation. X-ray diffraction and selected area electron diffraction results showed that the nanorods were anatase, while the semipheres also contained the TiO2(B) phase. By taking samples during the particle growth, it was found that the average length of the initially grown NRs decreased during the synthesis. Possible reasons for this unusual growth path, partially based on high-resolution transmission electron microscopy (HRTEM) observations during the growth, were discussed. The dispersion of anatase TiO2 nanorods was capable of spontaneous formation of lyotropic liquid crystals on the TEM grid and in bulk. Considering high colloidal stability together with the large optical birefringence displayed by these high refractive index liquid crystalline domains, we believe these TiO2 NRs dispersions are promising candidates for application in transparent and switchable optics.

Non-hydrolytic sol–gel route to a family of hybrid mesoporous aluminosilicate ethanol dehydration catalysts

Hybrid materials are intensely studied for potential applications in heterogeneous catalysis. Organic groups at the catalyst surface can modify not only its hydrophilicity, but also acidity, hydrothermal stability, porosity, etc. In some cases, tuning such properties leads to improved catalytic performance. Often, however, the organic moieties are limited to methyl groups introduced via post-grafting. Here, a series of mesoporous hybrid aluminosilicate materials was prepared in one pot by non-hydrolytic sol–gel (NHSG). Aromatic, aliphatic, pendant, and bridging organic groups were incorporated. The presence of the organic groups in the bulk and at the outermost surface of the materials was verified by solid-state NMR, IR, ToF–SIMS, and XPS. The hybrid aluminosilicates were tested as catalysts in the gas phase ethanol dehydration to ethylene, and most of them outperformed the inorganic catalyst benchmark. While a direct influence of surface hydrophobicity (as probed by water sorption and water contact angle measurements) appeared unlikely, characterization of acidity (IR-pyridine) revealed that the improved performance for hybrid catalysts could be correlated with a modification of the acidic properties. The latter are determined by the quality of the dispersion of Al centers in the form of isolated sites in the hybrid silica matrix, which itself appears to be influenced by the presence of organic groups in the non-aqueous synthesis. All in all, this study establishes a "ranking" for a variety of organic groups in terms of their influence on the catalyst activity.

One-step non-hydrolytic sol-gel synthesis of mesoporous SiO2-Al2O3-NiO catalysts for ethylene oligomerization

Mesoporous SiO2-Al2O3-NiO mixed oxide catalysts with different Si/Al ratio and a Ni content of ≈5.5 wt% have been prepared by a simple, one-step non-hydrolytic sol-gel route and evaluated in the oligomerization of ethylene. The catalysts were characterized by TEM-EDX, N2-physisorption, NH3-TPD, powder XRD, 29Si and 27Al MAS-NMR, XPS, and H2-TPR. The Si/Al ratio was found to influence both the texture and the acidity of the materials. According to XRD, part of the Ni formed NiO crystallites, but according to XPS, no bulky NiO was detected at the surface of the catalysts. XPS spectra and TPR experiments are consistent with the formation of dispersed Ni2+ species strongly interacting with the surface. The samples with high Al content displayed excellent performances with very high specific activity up to 270 mmol ethylene converted per g of catalyst per hour at 150 °C, and a percentage of butenes in the products of ≈70%. These catalysts compare well with model catalysts prepared by time-consuming multistep procedures from expensive ordered mesoporous silica supports.

Non-hydrolytic sol–gel as a versatile route for the preparation of hybrid heterogeneous catalysts

The tools of sol–gel chemistry allow synthesizing a plethora of functional materials in a controlled bottom-up fashion. In the field of heterogeneous catalysis, scientists utilize sol–gel routes to design solids with tailored composition, texture, surface chemistry, morphology, dispersion, etc. A field of investigation which shows great promises is that of hybrid heterogeneous catalysts. Examples are flourishing to show that catalysts featuring a combination of inorganic and organic components often display improved activity, selectivity, or even chemical stability as compared to the purely inorganic counterparts. Yet, classic sol–gel methods face some well-known limitations—related to the different reactivity of the precursors and to the high surface tension of water—which complicate the tasks of chemists, specifically for the synthesis of hybrid catalysts. Non-hydrolytic sol–gel (NHSG) chemistry appears as a pertinent alternative. Being realized in the absence of water, NHSG routes allow reaching an excellent control over the solid properties and on the distribution of the organic and inorganic components at the nano- and microscales. In this review, we briefly recapitulate the main types of non-hydrolytic sol–gel routes and we present the modified protocols to hybrid materials. Then, we present an overview of the non-hydrolytic sol–gel approaches that have been proposed to synthesize hybrid heterogeneous catalysts. For both Class I and Class II hybrids, we discuss how the NHSG technique has allowed tailoring the key properties that command catalytic performance. From this panorama, we argue that NHSG has a prominent role to play for the development of advanced hybrid heterogeneous catalysts.

Er3+/Yb3+-Doped GdVO4 Obtained by the Non-Hydrolytic Sol-Gel Route and Potential Application as Up-Conversion Thermometer

Er3+/Yb3+-Doped GdVO4 Obtained by the Non-Hydrolytic Sol-Gel Route and Potential Application as Up-Conversion Thermometer

NIR Luminescence Enhancement of YVO4:Nd Phosphor for Biological Application.

This work reports two systematic studies related to yttrium vanadate (YVO4) phosphors. The first evaluates how the annealing temperature and V5+/Y3+ molar ratio determine the emergence of a single YVO4 tetragonal phase, whereas the second concerns the optimal Nd3+ concentration to improve the infrared emission properties for bio-labelling applications. The YVO4:Nd phosphors were synthesized by adapting the non-hydrolytic sol-gel route. For the first study, samples containing different V5+/Y3+ molar ratios (1.02, 1.48, 1.71, or 3.13) were obtained. For the second study, YVO4:Nd phosphors containing different Nd3+ concentrations (1.0, 3.0, 5.0, or 10.0% in mol) were prepared. X-ray diffractometry and RAMAN spectroscopy results revealed that, regardless of the heat-treatment temperature, the V5+/Y3+ molar ratio of 1.48 was the best composition to avoid undesired phases like Y2O3 and V2O5. Photoluminescence results indicated that the sample containing 3.0% in mol of Nd3+ and annealed at 1000°C presented the best infrared emission properties. This sample displayed an intense broad band in the ultraviolet region, which was ascribed to the VO43- charge transfer band, as well as several bands in the visible and infrared regions, which were attributed to the Nd3+ intraconfigurational f-f transitions. Regardless of the excitation wavelength (ultraviolet, visible, or near-infrared), the mean radiative lifetime was about 12.00 µs. The prepared phosphors presented absorption and emission bands in the biological window (BW) regions, which are located between 750 and 900nm and between 1000 and 1300nm, so they are candidates for applications in medical imaging and diagnoses.

TinO2n-1 Suboxide Phases in TiO2/C Nanocomposites Engineered by Non-hydrolytic Sol-Gel with Enhanced Electrocatalytic Properties.

We report a non-hydrolytic sol-gel (NHSG) route to engineer original mesoporous TinO2n−1@TiO2/C nanocomposites. The synthetic approach is straightforward, solvent-free, additive-free, and meets the challenge of atom economy, as it merely involves TiCl4 and THF in stoichiometric amounts. We found that these nanocomposites present enhanced electrocatalytic properties towards the oxygen reduction reaction (ORR) in 0.1 M KOH. We believe that these preliminary results will open a window of opportunity for the design of metal suboxides/carbon nanocomposites through NHSG routes.

Water-Stable, Nonsiliceous Hybrid Materials with Tunable Porosity and Functionality: Bridged Titania-Bisphosphonates

Combining the properties of organic and inorganic moieties with high surface areas and pore volumes offers endless possibilities to design materials adapted to a wide range of advanced applications. The vast majority of mesoporous hybrid materials are siliceous materials, and developing low-cost synthetic methodologies leading to water stable nonsiliceous hybrid materials with controlled texture and functionality is essential. We report here an original strategy for the synthesis of mesoporous bridged titania-bisphosphonate hybrids based on a one-step, templateless nonhydrolytic sol–gel route. The reaction of Ti(OiPr)4 and a rigid bisphosphonate ester in the presence of Ac2O leads to the formation of TiO2 anatase nanorods cross-linked by fully condensed bisphosphonate groups. The porosity can be readily adjusted over a wide range by changing the reaction conditions, and very high specific surface areas (up to 720 m2 g–1) and pore volumes (up to 1.85 cm3 g–1) can be reached. The texture is stable in aqueous media between pH 1 and pH 12. Furthermore, accessible functional organic groups can be easily incorporated using either functional bisphosphonates or easily available monophosphonate compounds. The accessibility of bipyridyl organic groups was checked by Cu2+ adsorption from aqueous solutions. The unique combination of texture, functionality, and stability displayed by bridged titania-bisphosphonates makes these promising materials complementary of other hybrid materials such as organosilicas, MOFs, or mesoporous metal phosphonates.