Catalytic properties of mesoporous materials supported heteropoly acids for Baeyer-Villiger oxidation of cyclic ketones

Assessing the Influence of Confinement on the Stability of Polyoxometalate-Functionalized Surfaces: A Soft Sequential Immobilization Approach for Electrochromic Devices

“…Various strategies have been actively explored to overcome these challenges and to create ordered nanostructures with POMs, but almost exclusively based on mesoporous particles (not thin films) and not necessarily applicable with all types of POMs. Ordered mesoporous silica (SBA-15, MCM-41, or MCM-48 families) can be used as host to load Keggin-type POMs by impregnation − or encapsulation, but the long-term stability is expected to be poor due to the electrostatic repulsion between the negatively charged silica surface and POM anions . Alternatives are the one-pot procedures involving cocondensation of the silica source with functionalized POMs (mainly with ionic liquid components, , but not only), or the use of amino-functionalized mesoporous silica to promote the accumulation of POMs onto the ammonium (i.e., protonated amine) moieties, − but again based on weak electrostatic interactions and with poor control of the amount of immobilized POMs.…”

“…Note that other materials have been also exploited as hosts for POMs, such as mesoporous carbon, titania, silica pillared clays, aluminophosphates, or even composites, mainly for applications in catalysis or energy storage. All the above examples rely on POM-containing mesoporous particles. − There are only very few examples of POMs immobilized in mesoporous silica films (i.e., the configuration expected for electrochromic applications), such as amino-functionalized mesoporous silica film impregnated with POM, or surfactant-encapsulated POM grafted in a silica hybrid film . Of related interest are the honeycomb hybrid films made of POM/surfactant, or the inverse opal POM films generated using a colloidal crystal template, but such films suffer from poor chemical stability in solution.…”

SiO2-Supported DMDAAC-Modified Heteropoly Acid as Highly Active and Stability Catalysts for Methacrolein Oxidation

“…In addition, supporting HPAs on high specific surface area carriers is also an effective measure to solve the problem of low specific surface area of heteropolyacids . HPAV/SiO 2 exhibited high activity but the selectivity to MAA was low, which was due to the decomposition of HPAV. , Keggin-type POMs loaded on silica gel can improve the dispersion of the active components.…”