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Fenton and Fenton-like Advanced Oxidation Processes (AOP) have obtained large applicative use for the removal of organic pollutants from wastewater. Herein, we discuss a novel bimetal Cu-Mn porous silica-supported Fenton-like AOP catalyst with interparticle mesoporosity working under neutral pH and UV-VIS irradiation (CuMnKIL with Mn/Si = 0.01, Mn/Cu = 0.06). The photocatalyst was prepared via solvothermal synthesis (Mn incorporation into porous silica support) followed by incipient wetness impregnation (Cu loading into Mn containing porous silica support) and was tested for the decomposition of methylene blue as a model dye. Copper addition significantly reduced Mn leaching from the porous silica support (from 60 to 30 %) and functioned also as additional surface adsorption site. CuMnKIL (Mn/Si = 0.01, Mn/Cu = 0.06) showed 20 % higher adsorption and 20 % lower efficiency if compared with MnKIL (Mn/Si = 0.01) in Fenton-like AOP system, however, addition of irradiation (photo-Fenton-like system) improved efficiency of Cu/MnKIL (Mn/Si = 0.01, Mn/Cu = 0.06) for 10 % if compared to MnKIL (Mn/Si=0.01) due to the additional •OH radicals produced by the decomposition of H2O2 by the light. No synergistic effects between Cu and Mn were recorded, meaning that Cu and Mn sites were acting as separate sites, which was confirmed with AR-TEM imaging as well as UV spectroscopy studies.

Thermal Energy Storage Materials (TESMs) may be the missing link to the “carbon neutral future” of our dreams. TESMs already cater to many renewable heating, cooling and thermal management applications. However, many challenges remain in finding optimal TESMs for specific requirements. Here, we combine literature, a bibliometric analysis and our experiences to elaborate on the true potential of TESMs. This starts with the evolution, fundamentals, and categorization of TESMs: phase change materials (PCMs), thermochemical heat storage materials (TCMs) and sensible thermal energy storage materials (STESMs). PCMs are the most researched, followed by STESMs and TCMs. China, the European Union (EU), the USA, India and the UK lead TESM publications globally, with Spain, France, Germany, Italy and Sweden leading in the EU. Dissemination and communication gaps on TESMs appear to hinder their deployment. Salt hydrates, alkanes, fatty acids, polyols, and esters lead amongst PCMs. Salt hydrates, hydroxides, hydrides, carbonates, ammines and composites dominate TCMs. Besides water, ceramics, rocks and molten salts lead as STESMs for large-scale applications. We discuss TESMs’ trends, gaps and barriers for commercialization, plus missing links from laboratory-to-applications. In conclusion, we present research paths and tasks to make these remarkable materials fly on the market by unveiling their potential to realize a carbon neutral future.

Crystal growth & design 19(6), 3130 - 3138 (2019). doi:10.1021/acs.cgd.8b01181, Manganese plays an important role in redox catalysis using zeolites as inorganic support materials, but the formation of the preferred redox manganese species (framework or extraframework) is still not well understood. Herein, the influence of the amount of manganese together with conventional and microwave-assisted hydrothermal synthesis paths on the formation of manganese species within the zeolite silicalite-1 (S-1) with MFI structure was investigated. It was found out that both synthesis procedures led to the formation of frameworkand extraframework manganese species, but in different molar ratios. However, theconventional synthesis procedure with all Mn/Si molar ratios generates moreframework Mn in comparison to the microwave procedure. Additionally, thediminution of the zeolite crystals to nanoscale from 100 to 200 nm was achievedvia the conventional procedure for the first time. UV−vis, Raman, and X-rayabsorption spectroscopic analyses revealed different local environments ofmanganese: Mn$^{3+}$ incorporated into the silicalite-1 framework as “frameworkmanganese” and Mn$^{2+/3+}$ present as “extraframework manganese” (Mn$_2$O$_3$, Mn$_3$O$_4$). TEM reveals the presence of Mn$_3$O$_4$nanorods. Both framework manganese and extraframework manganese exhibit good catalytic activity for styrene epoxidation.Catalytic results suggest that, in oxidation reactions of hydrocarbons, framework manganese is more active at lower Mn contents(Mn/Si < 0.015), whereas extraframework manganese is more active at higher loadings (Mn/Si > 0.015)., Published by ACS Publ., Washington, DC

The structure–property relationship of catalytic supports for the deposition of redox-active transition metals is of great importance for improving the catalytic efficiency and reusability of the catalysts. In this work, the role of alumina support precursors of Cu-Fe/Al2O3 catalysts used for the total oxidation of toluene as a model volatile organic air pollutant is elucidated. Surface characterization of the catalysts revealed that the surface area, pore volume and acid site concentration of the alumina supports are important but not the determining factors for the catalytic activity of the studied catalysts for this type of reaction. The determining factors are the structural order of the support precursor, the homogeneous distribution of the catalytic sites and reducibility, which were elucidated by XRD, NMR, TEM and temperature programed reduction (TPR). Cu–Fe/Al2O3 prepared from bayerite and pseudoboehmite as highly ordered precursors showed better catalytic performance compared to Cu-Fe/Al2O3 derived from the amorphous alumina precursor and dawsonite. Homogeneous distribution of FexOy and CuOx with defined Cu/Fe molar ratio on the Al2O3 support is required for the efficient catalytic performance of the material. The study showed a beneficial effect of low iron concentration introduced into the alumina precursor during the alumina support synthesis procedure, which resulted in a homogeneous metal oxide distribution on the support.

For the photocatalytic wastewater treatment containing lower concentrations of dyes as pollutants, a suitable photocatalyst may be selected for anionic or cationic dye removal according to the photocatalyst surface charging and desired adsorption/degradation ratio. Herein, for the first time, we evaluate mesoporous silica supported TiO 2 versus mesoporous silica supported ZnO photocatalysts at neutral pH and at equal conditions. The evaluation shows that model anionic dye Reactive Blue 19 (RB19) was adsorbed onto silica supported ZnO nanoparticles at neutral pH in a much higher rate than on silica supported TiO 2 nanoparticles, even though the surfaces of ZnO and TiO 2 –silica composite catalysts were negatively charged in both cases (ca. −20 mV of zeta potential). This was ascribed to the strong positive zeta potential of pure ZnO nanoparticles at neutral pH value (ca. +37 mV) and consequently to more mixed oxide (spinel-like) ZnO/silica composite behaviour if compared to the physical mixture of oxide TiO 2 /silica composites. The highest dye adsorption (50%) and the fastest dye degradation (k app = 0.0544 min −1 at 25 °C) was observed on disordered ZnO/silica with Zn:Si molar ratio 1:1. Pure TiO 2 or silica supported TiO 2 nanoparticles were stable under UV irradiation. On the other hand, the interaction between SiO 2 and ZnO resulted in increased resistance of ZnO to photocorrosion, which was proven to be an issue in pure ZnO nanoparticles.

The sustainable generation of energy and low-energy consuming technologies are two main approaches to combat climate change and reduce carbon dioxide emissions. Sorption heat storage is part of the second approach. Therefore, adsorbents that achieve high energy storage density under the working conditions of the storage application are required. In this study, the hydrophilic properties of a granulated binder-free zeolite NaY were tailored with the aim of increasing its performance at a desorption temperature of 140 °C for mobile sorption heat storage. Top-down approaches, such as chemical treatment with the chelating agent H4EDTA, treatment with the inorganic acid HCl and sequential ion exchange with acid treatment, were used in order to decrease the desorption temperature and optimize the low-temperature heat storage density. All the modified samples showed a decrease in the desorption temperature from 10 to 30 °C compared to the parent sample; only the desorption temperature of the acid-treated Mg-exchanged NaY sample increased. The effect of different treatments on the structural properties of the materials, including the generation of framework defects and mesoporosity was determined. The energy storage densities of the NaY and all the modified samples are considerably higher in comparison to the currently used adsorbent (NaMSX) in mobile sorption heat storage for low-temperature industrial waste heat recovery.

Zirconia nanomaterials were prepared by impregnation of KIL-2 type silica with 4, 8, 15 and 25 wt% of ZrO2, and were modified by sulfate groups in order to vary the type, strength and density of the active sites. The samples were characterized by X-ray powder diffraction (XRD), EDX analysis, N2 physisorption, SEM, TEM, UV–Vis spectroscopy, XPS, and thermogravimetric analysis (TGA). The acidic properties were investigated by FT-IR spectroscopy of adsorbed pyridine. The catalytic properties of ZrKIL-2 catalysts and their sulfated varieties were studied in levulinic acid (LA) esterification with ethanol or n-butanol. The sulfated materials showed significantly higher activity compared to the non-sulfated ones due to their stronger Bronsted and Lewis acid sites. It was found that the silica supported sulfated samples show different activity depending on the applied alcohol. With increasing ZrO2 content up to 15 wt% increasing catalytic activity and selectivity was observed to produce levulinate esters. A further increase of the amount of zirconia leads to a decrease in catalytic activity because of the significant decrease of ZrO2 dispersion and the structure deterioration of the catalyst. For the first time insight was provided into the relation between sulfates group leaching and zirconia dispersion.

Zirconia nanomaterials were prepared by hydrothermal synthesis with or without template and were modified by post synthesis method with sulfate groups. The materials were thoroughly characterized by X-ray powder diffraction, TEM, N2 physisorption, FTIR spectroscopy of adsorbed pyridine TG analysis and XPS spectroscopy. The catalytic performance of nanosized ZrO2 catalysts and their sulfated modifications was studied in levulinic acid esterification with ethanol. The sulfate group’s dispersion was predetermined by the use of template during the mesoporous zirconia synthesis. A relation between sulfate groups leaching and the applied synthesis conditions (with or without template) of the zirconia nanoparticles was found. Sulfated materials showed significantly higher activity compared to non-sulfated ones. Furthermore, it has been found that the presence of template during the mesoporous ZrO2 nanoparticles preparation influences significantly the zirconia phase and catalytic performance in levulinic acid esterification.

Monometallic (CuO and FeOx) and bimetallic (CuFeOx) entities on different supports are promising transition-metal low-cost catalysts for catalytic oxidation of volatile organic compounds (VOC) from industrial air alternatively to noble-metal catalysts which are currently in use. In this work we report for the first time that the promotion of catalytic oxidation of toluene as a model VOC is due to the cooperative redox effect between CuO nanocrystals and finely dispersed Cu-oxo-Fe clusters on mesoporous silica with defined Fe/Cu molar ratio. This increases the number and reactivity of adsorbed electrophilic (O− and O2−) as well as nucleophilic lattice oxygen (O2-) species at the CuO crystal and and Cu-oxo-Fe cluster interface, thus providing up to twofold enhancement in catalytic activity for total oxidation of toluene. Catalysts were prepared via direct synthesis of Fe-functionalized disordered mesoporous silica containing only isolated iron sites followed by copper addition via impregnation.

Microporous zeolite-like aluminophosphate AlPO4-34 is a very promising material for water-adsorption-based thermal energy storage. To obtain better understanding of the dehydration of this material, a detailed variable-temperature nuclear magnetic resonance (NMR), X-ray diffraction (XRD), and first-principles calculation study was carried out. Unlike the previous studies, this one detected three distinct phase transitions during dehydration. The fully hydrated phase of AlPO4-34 first loses one water molecule per unit cell and transforms into the partly dehydrated phase I (space group P1). The molecule that was expelled first is the molecule that was initially located within the double six-membered ring and was very weakly coordinated to the aluminium atom and not involved in hydrogen bonds. During the second phase transition a water molecule is expelled from each chabazite cage. The obtained partly dehydrated phase II (space group P) contains six water molecules in each chabazite cage and four water molecules coordinated to octahedral aluminium. The third transition leads to the completely dehydrated material. Structures of both partly dehydrated phases of AlPO4-34 were determined by the Rietveld method. Variable-temperature NMR and XRD detected very different phase-transition temperatures. This was due to very different sample packing, which significantly influenced the rate of water removal. The confirmation that the two techniques observed the same phases of AlPO4-34 was obtained by the first-principles calculations of NMR observables. Using the XRD-based structural models, the calculations predicted 31P and 27Al isotropic chemical shifts that agreed well with the observed ones.

A new environmental friendly technology was developed for the preparation of highly crystalline binder-free zeolite ZSM-5 granules. It comprises a preparation of amorphous aluminosilicate granules by using inexpensive industrial reactants like sodium water glass and sodium aluminate without the use of organic structure directing agents. Dried aluminosilicate gel was compacted in granules by using sodium water glass as a “pseudo-binder”. Zeolite ZSM-5 granules were prepared by hydrothermal crystallization at 180 °C after 24 h by using lifted set-up reactor in 0.01 M NaOH comprising 10 wt% of amorphous aluminosilicate granules. The influence of crystallization temperature and time, SiO 2 /Al 2 O 3 molar ratio of reactants and relationship between the amount of amorphous aluminosilicate granules and NaOH medium during hydrothermal treatment on the crystallization process of granulated ZSM-5 product were monitored and characterized by X-ray diffraction, X-ray fluorescence, scanning electron microscope, and N 2 physisorption technique. The presented procedure enabled more than doubled increase of the synthesis product yield, which positively impacts the economy and ecology of the production process.

cited By 11; International audience; Discharge/charge process of classical lithium sulphur battery proceeds through intermediate polysulphides which are soluble in classical electrolyte systems. Due to concentration gradient soluble polysulphides easily diffuse/migrate out from cathode composite forming non-uniform distribution of the sulphur within cathode. Eventually polysulphides can be completely reduced on the metallic lithium anode. In this work we compare the sorption properties of manganese modified zeolite silicalite-1 (MnS-1) with a cathode composite containing SBA-15 additive and a cathode composite without additive. Careful analysis using XPS and FIB microscopy equipped with EDX show improved retention of polysulphide species within cathode composite in the case of MnS-1 zeolite as an additive. Interestingly, the amount of sulphur species detected by XPS on the metallic lithium is very similar regardless on cathode composite we use. Finally, similar cycling behaviour can be observed if MnS-1 zeolite is used as an interlayer between composite cathode and separator. © 2014 Elsevier B.V.

Zirconia nanomaterials were prepared by impregnation of KIL-2 type silica with 4, 8 and 12 wt.% ZrO2 and were modified by sulphate groups in order to vary the type and strength of acidity. Samples were characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), and N2 physisorption methods. Acidic properties of adsorbed pyridine were investigated by FT-IR spectroscopy. The catalytic performance of ZrKIL-2 and SO42−/ZrKIL-2 in glycerol esterification with acetic acid was studied and compared to that of pure zirconia varieties. It was found that silica-supported zirconia samples are more active than pure zirconia ones. With increasing ZrO2 content, KIL-2-supported catalysts showed increasing catalytic activity and selectivity in producing valuable fuel additives, di- and triacetyl glycerols. Sulphated analogues showed even higher activity and selectivity compared to non-sulphated ones due to their strong Bronsted acidity.

Cobalt-containing porous silicas were prepared by incipient wetness impregnation with different salt precursors. We compare cobalt-containing silica with interparticle mesoporosity (Co/KIL-2) to mesoporous silica (Co/SBA-15) in total toluene oxidation. Different cobalt species were detected in dependence on the kind of the salt precursor used. Lower production costs and high catalytic activity and stability of Co/KIL-2 make KIL-2 a promising support for volatile organic compounds elimination.

Two different composites, one with disordered mesoporous iron silicate matrix and the other with ordered mesoporous matrix together with calcium chloride, are presented. The introduction of CaCl2 in the matrices improves the maximal water sorption capacity. The composite with disordered mesoporous matrix showed a maximal water uptake of 0.58 g/g at 5.6 kPa, while the composite with ordered mesoporous matrix revealed higher maximal water uptake of 0.88 g/g. These composites show good hydrothermal stability after 20 cycles of sorption/desorption between temperatures of 150 °C and 40 °C and at water vapor pressure of 5.6 kPa. After the cycling test no leakage of the salt hydrate from the composites was detected.

Copper-supported catalysts are of industrial importance in many catalytic processes. Mesoporous silica materials are of particular interest as green heterogeneous catalyst supports. In the present study we demonstrate the nature and reduction properties of copper oxide species, which are influenced by the peculiarity of the silica nanoparticles with interparticle mesoporosity (KIL family) and the presence of a second metal (iron) in the silica matrix. The copper-containing KIL-2 and FeKIL-2 samples are prepared by incipient wetness impregnation. The reduction of copper oxide species is easier on the FeKIL-2 supported sample in comparison to its KIL-2 supported analogue, whereas the copper-containing KIL-2 sample shows higher catalytic activity in total toluene oxidation. The presence of iron in the FeKIL-2 structure leads to autoreduction of copper followed by the redispersion and oxidation of metallic copper in the reaction medium; this results in the formation of different types of finely dispersed copper oxide species (

The utilization of the reversible chemical and physical sorption of water on solids provides a new thermal energy storage concept with a great potential for lossless long-term storage. The performance of microporous aluminophosphates in heat storage applications is highlighted by a comparative thermogravimetric and calorimetric study of three known materials (SAPO-34, AlPO 4 -18, APO-Tric) and is correlated with their structural features. The maximum water sorption capacity is similar for all three samples and results in a stored energy density of 240 kWh m − 3 in the 40–140 o C range. The elemental composition infl uences the gradual (silicoaluminophosphate SAPO-34) or sudden (aluminophosphates AlPO 4 -18, APO-Tric) water uptake, with the latter being favourable in storage systems. The driving force for the determined sorption process is the formation of highly ordered water clusters in the pores, which is enabled by rapid and reversible changes in the Al coordination and optimal pore diameters. The ease with which changes in the Al coordination can occur in APO-Tric is related to the use of the fl uoride route in the synthesis. The understanding of these fundamental structure/sorption relationships forms an excellent basis for predicting the storage potential of numerous known or new microporous aluminophosphates and other porous materials from their crystal structures.

The influence of microwave synthesis conditions (time, temperature) and aging of clear solutions on the size, morphology, iron content, and aggregation of nanocrystalline particles were studied for iron silicalite-1 (FeS-1). The compound crystallized from a starting clear solution (10TEOS : 0.2FeCl3 : 3TPAOH : 245H2O) using one- and two-step microwave-assisted hydrothermal syntheses. The smallest round FeS-1 intergrown crystals with a mean diameter of 300 nm composed of 40 nm particles were obtained by two-step microwave-assisted hydrothermal syntheses. The study of iron local structure in FeS-1 by using UV-Vis and Mossbauer spectroscopy revealed the presence of framework and extra-framework iron species. A reaction of N2O decomposition to N2 and O2 was used as a test to confirm higher catalytic activity of smaller crystallite size.

Ordered (SBA-15) and disordered (KIL-2) mesoporous silica supports have been synthesized and used for incorporation of titania with different Ti/Si molar ratios (1/2, 1/1, 2/1) via sol–gel impregnation method. Titanium isopropoxide and aqueous titania sol prepared by low-temperature sol–gel processing were used as a source of titania. Characterization by powder X-ray diffraction (XRD), nitrogen sorption measurements, scanning electron microscopy (SEM) and UV–vis–NIR diffuse reflectance spectroscopy (DRS) has been carried out to investigate the chemical framework and morphology of powders. The photocatalytic degradation of isopropanol in the gaseous medium was selected as a probe reaction to test the photoactivity of powders and to verify the potential application of these materials for air remediation. It was found that the titania source, Ti/Si molar ratio and the type of silica support influenced the functional properties of the material, which were evaluated by adsorption capacity and photocatalytic activity in the gas–solid reactor. The adsorption capacity of isopropanol was the highest in the presence of the SBA-15-supported materials. The photoactivity results indicated that the powders which were prepared using SBA-15 as a silica support and a Ti/Si molar ratio of 1/1 were the most active towards isopropanol oxidation monitored in situ by FT-IR spectroscopy.

4th International Conference on Solar Heating and Cooling for Buildings and Industry (SHC) -- DEC 02-04, 2015 -- Istanbul, TURKEY, WOS: 000387506400026, An overview on the recent results on the engineering and characterization of sorption materials, PCMs and TCMs investigated in the working group WG A1 "Engineering and processing of TES materials" of IEA SHC Task 42 / ECES Annex 29 (Task 4229) entitled "Compact Thermal Energy Storage" is presented. (C) 2016 The Authors. Published by Elsevier Ltd.

Mesoporous silicate catalyst FeTUD-1 containing only isolated iron was synthesized. Local environment of iron was investigated by X-ray Absorption and Mossbauer spectroscopies. XANES (X-ray Absorption Near Edge Structure) studies show that iron in the as-synthesized and template-free FeTUD-1 is present in the form of Fe3+ ions in coordination geometries posses an inversion center. EXAFS (X-ray Absorption Fine Structure) analyses reveal that iron cations in the as-synthesized sample are coordinated to four oxygens at the distance of 1.87 A and in the template-free sample to one oxygen at 1.86 A and five oxygens at 2.0 A distances. Mossbauer spectroscopy proves the presence of iron in Fe3+ form in template-free sample. Moreover, it determines Fe3+ in two types of distorted octahedral coordinations.

Thermally stable titanium-containing microporous/mesoporous composite (Ti, Al)-Beta/MCM-48 was synthesised hydrothermally in the presence of structure-directing agents cetyltrimethylammonium bromide (CTABr), polyoxyethylene(8) isooctylhexyl ether (Triton ® X-114) and tetraethylammonium hydroxide (TEAOH) in the absence of sodium cations. The presence of both microporous and mesoporous phases was determined by XRD and HRTEM measurements and by the analysis of nitrogen adsorption isotherm based on the α -plot method. The mass percentage ( μ ) of the microporous material in the composite is approximately 6.5%. NMR investigations showed that acid sites related to framework aluminium were generated by calcination of the as-synthesised (Ti, Al)-Beta/MCM-48. Local environment of titanium incorporated into the microporous/mesoporous silicate material was investigated by X-ray absorption spectroscopy. XANES studies showed the presence of tetrahedrally-coordinated Ti 4+ cations in the template-free sample. EXAFS analysis revealed that titanium cations were coordinated to four oxygens in the first coordination shell, to one oxygen at 1.73(1) A and three oxygens at 1.86(1) A. In the second coordination sphere three silicon atoms were found at distances 3.18(2) A and 3.48(2) A, respectively. These results indicated framework Ti and thus the presence of Ti oxidation centres within the composite material.

SBA-16 silica was synthesized and modified by post-synthesis method with amino groups. Wet milling in acidic media was applied for loading of poorly soluble drug mesalazine (5-aminosalicylic acid — 5-ASA) in different drug/carrier ratios (1:1; 0.75:1; 0.5:1; 0.25:1). The parent and drug loaded mesoporous silicas were characterized by XRD, TEM,N2 physisorption, thermal analysis, FT-IR and solid state NMR spectroscopy. The drug loaded mesoporous systems were single-coated with Eudragit S or double-coated with Eudragit S and Eudragit RL. The polymer coating significantly modified the rate of mesalazine release fromS BA-16NH2 materials. Applying the double coating method makes possible the sustained delivery of the drug in the intestinal area avoiding the burst release in the gastric fluid. The functionalized, polymer coated mesoporous system could be considered an appropriate oral delivery system for mesalazine. In addition, reduction of mesalazine cytotoxicity on epithelial cells could be achieved by its loading into mesoporous silica particles.

Manganese-modified hexagonal mesoporous aluminophosphate (MnHMA) was synthesized hydrothermally in a microwave oven in the presence of cetyltrimethylammonium chloride (CTACl) as a template. The mesoporous structure was elucidated by HRTEM. Local environment of aluminum and phosphorus forming the mesoporous aluminophosphate framework was studied by MAS NMR. The local environment of manganese incorporated in HMA was investigated by X-ray absorption spectroscopy. XANES studies show that manganese in the as-synthesized and template-free MnHMA is present in the form of Mn 2+ and Mn 3+ ions in the ratio 40–60%. EXAFS analyses revealed four oxygens in the first coordination sphere of manganese in the as-synthesized and template-free MnHMA at the distances 2.142(5) A and 2.15(1) A, respectively. EPR and ESEEM measurements revealed that Mn 2+ in both as-synthesized and template-free products was located within the mesoporous aluminophosphate framework.

Iron-containing hexagonal mesoporous aluminophosphate (FeHMA) was synthesised hydrothermally in a microwave oven in the presence of cetyltrimethylammonium chloride (CTACl) as a template. The local environment of aluminium and phosphorus forming the aluminophosphate walls was studied by MAS NMR. The local environment of iron incorporated in HMA was investigated by X-ray absorption spectroscopy (XAS). X-ray absorption near edge structure (XANES) studies showed that iron in the as-synthesised and template-free FeHMA was present predominantly in the form of octahedrally coordinated Fe 3+ ions. X-ray absorption fine structure (EXAFS) analyses confirmed that iron cations in the as-synthesised and template-free FeHMA were in octahedral coordination with the Fe–O distances of 1.97 A. Mossbauer spectroscopy revealed the presence of octahedrally coordinated Fe 3+ and also tetrahedrally coordinated Fe 2+ in the template-free FeHMA in the ratio of 4:1, which could not be detected by XANES. After the thermal treatment of template-free FeHMA at 427 °C in vacuum the Mossbauer spectra showed that almost half of the iron cations present in the sample were tetrahedrally coordinated. The framework positions of tetrahedrally coordinated Fe 2+ and octahedrally coordinated Fe 3+ are suggested.

The incorporation of moderate amounts of Ni(II), Co(II), Fe(II/III), and Mn(II/III) into aluminophosphate zeotype AlPO4-34 and Fe(II/III) into aluminophosphate zeotype AlPO4-36 was studied by broadline 31P NMR. The technique provided direct evidence on isomorphous substitution of framework aluminum by transition metals and allowed us to determine the extent of the substitution. 31P NMR proved to be complementary to other spectroscopic techniques such as X-ray absorption spectroscopy (XAS), Mössbauer, electron paramagnetic resonance (EPR), and electron nuclear double resonance (ENDOR) spectroscopies. The position of the NMR signal belonging to phosphorus in the P(OAl)3(OMe) environment depended mostly on the magnitude of the hyperfine interaction between a phosphorus nucleus and an unpaired electron, which was delocalized from the transition metal atom Me by covalent bonding. The width of the NMR signal was dominated by dipolar coupling among phosphorus nuclei and nearest paramagnetic centers. In addition, broadline NMR of ethylenediamine-templated manganese phosphate (C2H10N2)[Mn2(HPO4)3(H2O)], which was used as a model compound, showed that on the basis of line positions and line widths different 31P signals could easily be assigned to different phosphorus crystallographic sites. The technique could thus be applied to extract valuable structural information about metal phosphates as well.

An extra-large pore iron-substituted aluminophosphate molecular sieve FeVPI-5 was synthesized. Elemental analysis indicated isomorphous substitution of aluminum by iron. X-ray absorption spectroscopy (XANES and EXAFS analyses) confirmed the incorporation of Fe(III) into the framework of VPI-5. The acidity tests of FeVPI-5, performed by IR spectroscopy using CO adsorption at low temperature on the oxidized and on the reduced material, gave evidence on redox behavior of framework iron in FeVPI-5.

Kinetics of the isothermal amorphization of zeolite 4A and recrystallization of the formed amorphous phase to low-carnegieite at three different temperatures were investigated by powder X-ray diffraction method. Changes in the fractions f A of zeolite 4A, f a of amorphous aluminosilicate and f C of low-carnegieite during heating of zeolite 4A, show that amorphization and recrystallization take place simultaneously. Kinetic analyzes of single processes (amorphization, recrystallization) as well as solution of the population balance of the entire transformation process (simultaneous transformation of zeolite 4A into amorphous aluminosilicate and its recrystallization into low-carnegieite) have shown that: (A) the transformation of zeolite 4A takes place by a random, diffusion-limited agglomeration of the short-range-ordered aluminosilicate subunits formed by thermally induced breaking of SiOSi and SiOAl bonds between different building units of zeolite framework; and (B) the crystallization of low-carnegieite occurs by homogeneous nucleation of low-carnegieite inside the matrix of amorphous aluminosilicate and diffusion-controlled, one-dimensional growth of the nuclei, thus forming needle-shaped crystals of low-carnegieite.

Triclinic ZnAPO-34 and triclinic FAPO-34 were synthesized by hydrothermal crystallization from zinc(II)- and iron(II)-containing gels. The products are thermally stable up to 900 °C. XANES and EXAFS analyses were applied to study the local environment of zinc in the ZnAPO-34 samples, while XANES analysis and Mossbauer spectroscopy were performed on the iron-substituted samples. Zn(II) remains in the same oxidation state during synthesis and after thermal treatment, while iron exhibits Fe(II) and Fe(III) oxidation states. Analysis of the local structure showed that Zn(II) is located on tetrahedral sites of the framework, while Fe(II) and Fe(III) are present on octahedral sites. Infrared study of carbon monoxide adsorption at 100 K showed the presence of strong Bronsted acid sites on the Zn and Fe(II) samples, indicating the substitution of the metals in the framework. Rhombohedral FAPO-34 can be reversibly oxidized in the infrared cell, evidencing the disappearance of the Bronsted acid sites in the Fe(III) oxidation state.

Zinc-, cobalt- and manganese-containing microporous gallophosphates (GaPOs) with the ULM-5 structure have been hydrothermally synthesized in the presence of fluoride ions and 1,6-diaminohexane as the structure-directing agent. X-ray diffraction, elemental and thermogravimetric analyses of ULM-5 and MeULM-5 (Me=Zn, Co, Mn) indicated the incorporation of 2 wt.% for Zn, 1 wt.% for Co and 0.5 wt.% for Mn into the GaPO framework. The UV–VIS spectrum collected on the as-synthesized CoULM-5 sample revealed five-coordinated cobalt(II) in the structure. X-ray absorption spectroscopy (EXAFS) showed that zinc(II), cobalt(II) and manganese(II) substituted gallium on non-tetrahedral sites in the MeULM-5 framework and revealed structural changes of ULM-5 and MeULM-5 in the calcination process. The template-free samples are not thermally stable in the ambient atmosphere.

The symmetry transformation of aluminophosphate molecular sieve AlPO4-31 and the interaction of its framework with dipropylamine template molecules were studied by variable temperature XRD and multinuclear MAS, CPMAS, and MQMAS NMR measurements. The as-synthesized material exhibited triclinic symmetry with a slightly distorted rhombohedral-like unit cell. Deviation from a rhombohedral symmetry was due to a large amount of template within cavities of a molecular sieve, which caused short contacts with the aluminophosphate framework. The template within AlPO4-31 was in the form of dipropylammonium hydroxide ionic pairs, whose arrangement did not possess a long-range order. Hydroxyl groups, not being isolated by surrounding alkyl groups, interacted with the aluminophosphate framework and gave rise to 5-coordinated aluminum sites. Dipropylammonium and hydroxyl groups were also coupled to the framework through hydrogen bonds with the framework oxygen and affected the local environments of the 4-coordinated alu...

The large-pore molecular sieve MnAPO-50 of pure, greenish yellow crystals up to 100×100×300 μm was synthesized hydrothermally in the presence of di-n-propylamine. The product is thermally stable up to 250°C in air and up to 430°C in vacuum. It transforms into the dense phases Mn2P2O7 and AlPO4-tridymite at 550°C in air and at 650°C in vacuum. The single-crystal X-ray structure analysis of the as-synthesized MnAPO-50 (trigonal, P3, a=12.746(1) A, c=9.140(1) A) served as direct evidence of the very high degree of incorporation of Mn into the tetrahedral framework. The presence of Mn and Al on both of the two non-phosphorus framework tetrahedral sites was revealed: the T sites on the general position and on the threefold axis were occupied by 86% of Al, 14% of Mn and 3% of Al, 97% of Mn, respectively. Thirty-five per cent of the non-phosphorus tetrahedral framework sites were thus occupied by Mn, which is in reasonable agreement with the formula (Mn0.186(6)Al0.309(9)P0.504(2))O2, calculated on the basis of the elemental analysis.

Manganese(II)/phosphate/organic template hydrothermal reactions were investigated with the aim of preparing novel crystalline porous materials. Ethylenediamine, isopropylamine, and piperidine were explored as organics that would be able to organize oxide moieties of Mn(II) and P(V) into a porous MnPO 4 crystalline lattice. The synthesis in the presence of ethylenediamine yields a product with the double protonated organic entrapped in the void space of the crystal. However, the products obtained in the presence of isopropylamine and piperidine do not contain any organics. It seems that the only role of isopropylamine and piperidine in the crystallization of MnPO material is that of a base. Total removal of the occluded species occurs at around 300°C, after which the manganese phosphate products become X-ray amorphous.

Hydrophilic porous materials are recognized as very promising materials for water-sorption-based energy storage and transformation. In this study, a porous, zeolite-like aluminophosphate with LTA (Linde Type A) topology is inspected as an energy-storage material. The study is motivated by the material's high predicted pore volume. According to sorption and calorimetric tests, the aluminophosphate outperforms all other zeolite-like and metal-organic porous materials tested so far. It adsorbs water in an extremely narrow relative-pressure interval (0.10 < p/p0 < 0.15) and exhibits superior water uptake (0.42 g g−1) and energy-storage capacity (527 kW h m−3). It also shows remarkable cycling stability; after 40 cycles of adsorption/desorption its capacity drops by less than 2%. Desorption temperature for this material, which is one of crucial parameters in applications, is lower from desorption temperatures of other tested materials by 10–15 °C. Furthermore, its heat-pump performance is very high, allowing efficient cooling in demanding conditions (with cooling power up to 350 kW h m−3 even at 30 °C temperature difference between evaporator and environment). On the microscopic scale, sorption mechanism in AlPO4-LTA is elucidated by X-ray diffraction, nuclear magnetic resonance measurements, and first-principles calculations. In this aluminophosphate, energy is stored predominately in hydrogen-bonded network of water molecules within the pores.

A new two-component (composite) water sorbent CaCl2-FeKIL2 has been developed for sorption-based solar thermal energy storage. The matrix of the composite is FeKIL2 material with disordered mesopores, high surface area of 712 m2/g and mesopore dimensions between 4 and 29 nm. The composite, prepared by wet impregnation of FeKIL2 with CaCl2, has lower surface area (418 m2/g) and similar mesopore dimensions as the matrix. The maximum water sorption capacity of FeKIL2 is 0.21 g/g, while the composite possesses 3 times higher maximum water sorption capacity due to the presence of the salt in the matrix. Heat of adsorption of the composite is 50.4 kJ/mol. A short-term cycling test between temperatures of 150 and 40 °C at a water vapour pressure of 5.6 kPa confirms a comparatively good hydrothermal stability of the composite.

A two-step synthesis of a novel mesostructured silicate, KIL-2, and its manganese-containing analogue, Mn/KIL-2, has been developed. KIL-2 possesses interparticle mesopores with pore dimensions between 5 and 60 nm and a surface area of 448 m2. The mesopores are formed by the aggregation of silica nanoparticles, which creates a network with interparticle voids. The particle size and the pore diameters depend on the temperature of the ageing step (first step) and on the solvothermal treatment in ethanol (second step), respectively. Mn/KIL-2 contains octahedrally coordinated Mn3+ (80 %) and tetrahedrally coordinated Mn2+ (20 %) ions. Mn3+ ions are present in the extra-framework MnOx nanoparticles with typical dimensions of 2 nm, which are homogeneously distributed throughout the material. Mn2+ ions occur as isolated manganese framework sites. The material is also able to retain its structure characteristics after the hydrothermal treatment in boiling water. Because of its non-toxic nature and cost-effective synthesis, Mn/KIL-2 thus exhibits properties that are needed for an environment-friendly catalyst.

A two-step synthesis of a novel mesostructured silicate, KIL-2, and its manganese-containing analogue, Mn/KIL-2, has been developed. KIL-2 possesses interparticle mesopores with pore dimensions between 5 and 60 nm and a surface area of 448 m(2). The mesopores are formed by the aggregation of silica nanoparticles, which creates a network with interparticle voids. The particle size and the pore diameters depend on the temperature of the ageing step (first step) and on the solvothermal treatment in ethanol (second step), respectively. Mn/KIL-2 contains octahedrally coordinated Mn(3+) (80%) and tetrahedrally coordinated Mn(2+) (20%) ions. Mn(3+) ions are present in the extra-framework MnO(x) nanoparticles with typical dimensions of 2 nm, which are homogeneously distributed throughout the material. Mn(2+) ions occur as isolated manganese framework sites. The material is also able to retain its structure characteristics after the hydrothermal treatment in boiling water. Because of its non-toxic nature and cost-effective synthesis, Mn/KIL-2 thus exhibits properties that are needed for an environment-friendly catalyst.