Water-soluble titanium-oxides: Complexes, clusters and nanocrystals

Chakraborty, Biswarup; Weinstock, Ira A.

doi:10.1016/j.ccr.2018.11.011

Cited by 59 publications

(32 citation statements)

References 111 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This exciting field has recently been exemplified for titanium oxide clusters as a model system for TiO 2 surfaces: the combination of Ti‐O molecular clusters with polyoxometalates has already been conceptually demonstrated, while the ramifications of these findings and new applications are waiting to be explored (Figure 8c). [ 98,101 ]…”

Section: Discussionmentioning

confidence: 99%

Polyoxometalates on Functional Substrates: Concepts, Synergies, and Future Perspectives

et al. 2020

View full text Add to dashboard Cite

POMs were studied as heterogeneous acid catalysts and oxidation catalysts. However, this approach is often affected by low specific surface areas, leading to reduced reactivity. [10] Later studies, therefore, pioneered the immobilization of POMs on high surfacearea substrates including porous silica and other metal oxides, [10] as well as more advanced materials such as carbon nanostructures [11] and metal-organic frameworks (MOFs). [9] This strategy can enable maximized exposure of the individual POM molecules to the reaction environment, and in addition, allows for facile separation by filtration or centrifugation. [12] While early studies on POM immobilization used heterogeneous supports for mechanical stabilization and maximized surface-area, more recent studies have moved toward added properties introduced by the support. These include light-absorption and charge transport by semiconductors (TiO 2 , CdSe, etc.), electrical conductivity (by carbons, metals, conductive polymers) as well as specific POM binding sites, as introduced in MOFs and organofunctionalized supports. Many contemporary studies in this field share a common interest in exploring the synergism between POM and substrate to tune and optimize reactivity and stability of the composite. The concept has been theoretically and experimentally described several decades ago as the so-called "microenvironment effect" (electronic charge enhancement) where entrapment of POM species in a 3D matrix has been shown to induce huge improvement of their electrocatalytic activity. [13][14][15] However, to-date, the understanding of the fundamental processes which govern synergism of POM-substrate interactions is still in its infancy, as mole cular-level understanding of these complex processes by experiment or theory is far from trivial. This is due to the vast number of materials combinations, which are currently studied, and is further complicated by the often unknown chemical structures of the POM-substrate interface which make theoretical studies difficult. Also, in situ/operando studies of these materials are still challenging, and instrumentational approaches to address these issues are still being developed and not widely available. Most current experimental studies, therefore, focus on macroscopic reactivity, while providing less insight into the underlying causes of the processes observed.This Progress Report aims at raising awareness of the vast benefits of exploring this under-researched area to enable full use of POM-substrate interactions including charge and energy transfer, band-gap, and frontier orbital alignment as well as interface design for stability and reactivity. These fundamental concepts can affect both the thermodynamics as well as the kinetics of the chemical processes studied so that new reactivity can be tailored by understanding of the interactions between POM and substrate. Given the fast-paced progress in the synthesis, application, and characterization of this materials class, this Progress Report will serve as a focal point for ...

show abstract

Section: Discussionmentioning

confidence: 99%

Polyoxometalates on Functional Substrates: Concepts, Synergies, and Future Perspectives

et al. 2020

View full text Add to dashboard Cite

show abstract

“…Considerable progress in crystalline Ti-O clusters has been achieved during the past few decades, leading to diverse structures with different numbers of Ti centers. [32][33][34][35][36] In most cases, the syntheses of Ti-O clusters require hydrolysis of Ti precursor under solvothermal conditions, which is always limited by long reaction time, low reaction yield, and small scale for further applications. In contrast, the Ti 8 AF cluster was prepared under reflux conditions with ambient pressure for a short duration, simply by heating the mixture of Ti(iPrO) 4 , formic acid, and acetic anhydride in a roundbottomed flask in contact with air.…”

Section: Resultsmentioning

confidence: 99%

Toward a Rational Design of Titanium Metal-Organic Frameworks

Wang

Reinsch

Heymans

et al. 2020

Matter

View full text Add to dashboard Cite

Titanium metal-organic framework (Ti-MOF) is an unexploited area due to its unpredictable chemistry in solution and, thus, the challenge of controlling the reaction process and product. By linker exchange with a Ti 8 O 8 cluster precursor, the first green scalable controlled synthesis of a Ti-MOF structure is achieved following both post-synthetic and one-pot reaction routes. The chemical functionality and environment of the MOF pore could be tuned easily by mixed linker, resulting in an adjustable performance in CO 2 capture over N 2 .

show abstract

“…When diluted solutions are re-concentrated by evaporation (at 40 C under vacuum) there is an increase of the viscosity, precluding complete solvent evaporation. From these results is evident that solutions at low concentration of TiBALDH (#100 mM) contain stable titanium species (complexes and/or oxide) and the intermolecular interactions are negligible, meanwhile in concentrated solutions, lactates could promote the formation and growth of micelles templated by self-assembly of ligands (MTSALs), 22,34,35 which would explain its reversible nature. This behavior is similar to the vitreous transition of polymers or ionic liquids, probably hydrogen bonds hamper the total water evaporation resulting in a very stable structure.…”

Section: Concentration-effectmentioning

confidence: 95%

TiBALDH as a precursor for biomimetic TiO₂ synthesis: stability aspects in aqueous media

et al. 2019

View full text Add to dashboard Cite

show abstract

Water-soluble titanium-oxides: Complexes, clusters and nanocrystals

Cited by 59 publications

References 111 publications

Polyoxometalates on Functional Substrates: Concepts, Synergies, and Future Perspectives

Polyoxometalates on Functional Substrates: Concepts, Synergies, and Future Perspectives

Toward a Rational Design of Titanium Metal-Organic Frameworks

TiBALDH as a precursor for biomimetic TiO₂ synthesis: stability aspects in aqueous media

Contact Info

Product

Resources

About

Water-soluble titanium-oxides: Complexes, clusters and nanocrystals

Cited by 59 publications

References 111 publications

Polyoxometalates on Functional Substrates: Concepts, Synergies, and Future Perspectives

Polyoxometalates on Functional Substrates: Concepts, Synergies, and Future Perspectives

Toward a Rational Design of Titanium Metal-Organic Frameworks

TiBALDH as a precursor for biomimetic TiO2 synthesis: stability aspects in aqueous media

Contact Info

Product

Resources

About

TiBALDH as a precursor for biomimetic TiO₂ synthesis: stability aspects in aqueous media