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Amino-alkylphosphonic acid-grafted TiO2 materials are of increasing interest in a variety of applications such as metal sorption, heterogeneous catalysis, CO2 capture, and enzyme immobilization. To date, systematic insights into the synthesis-properties-performance correlation are missing for such materials, albeit giving important know-how towards their applicability and limitations. In this work, the impact of the chain length and modification conditions (concentration and temperature) of amino-alkylphosphonic acid-grafted TiO2 on the surface properties and adsorption performance of palladium is studied. Via grafting with aminomethyl-, 3-aminopropyl-, and 6-aminohexylphosphonic acid, combined with the spectroscopic techniques (DRIFT, 31P NMR, XPS) and zeta potential measurements, differences in surface properties between the C1, C3, and C6 chains are revealed. The modification degree decreases with increasing chain length under the same synthesis conditions, indicative of folded grafted groups that sterically shield an increasing area of binding sites with increasing chain length. Next, all techniques confirm the different surface interactions of a C1 chain compared to a C3 or C6 chain. This is in line with palladium adsorption experiments, where only for a C1 chain, the adsorption efficiency is affected by the precursor concentration used for modification. The absence of a straightforward correlation between the number of free NH2 groups and the adsorption capacity for the different chain lengths indicates that other chain-length-specific surface interactions are controlling the adsorption performance. The increasing pH stability in the order of C1 < C3 < C6 can possibly be associated to a higher fraction of inaccessible hydrophilic sites due to the presence of folded structures. Lastly, the comparison of adsorption performance and pH stability with 3-aminopropyl(triethoxysilane)-grafted TiO2 reveals the applicability of both grafting methods depending on the envisaged pH during sorption. ispartof: ACS OMEGA vol:7 issue:49 pages:45409-45421 ispartof: location:United States status: published

Lithium−sulphur batteries attract increasing interest due to their high theoretical specific capacity, advantageous economy, and “eco-friendliness”. In this study, a metal-organic framework (MOF) GaTCPP containing a porphyrinic base ligand was used as a conductive additive for sulphur. GaTCPP was synthesized, characterized, and post-synthetically modified by the transition metal ions (Co2+/Ni2+). The doping of GaTCPP ensured an increase in the carbon dioxide adsorption capacities, which were measured under different conditions. Post-synthetic modification of GaTCPP with Co2+/Ni2+ ions has been shown to increase carbon dioxide storage capacity from 22.8 wt.% for unmodified material to 23.1 wt.% and 26.5 wt.% at 0 °C and 1 bar for Co2+ and Ni2+-doped analogues, respectively. As a conductive part of cathode material, MOFs displayed successful sulphur capture and encapsulation proven by stable charge/discharge cycle performances, high-capacity retention, and Coulombic efficiency. The electrodes with pristine GaTCPP showed a discharge capacity of 699 mAh g-1 at 0.2 C in the fiftieth cycle. However, the doping of GaTCPP by Ni2+ has a positive impact on the electrochemical properties, the capacity increased to 778 mAh g-1 in the fiftieth cycle at 0.2 C.

The Stöber method is one of the most important and fundamental processes for the synthesis of inorganic (nano)materials, but has the drawback of using a large amount of organic solvent. Herein, we used ethanol as an example to explore if the organic solvent in a typical Stöber method can be omitted. We found that ethanol increases the particle size of the obtained silica spheres and aids the formation of uniform silica particles rather than forming a gel. Nevertheless, the results indicated that an organic solvent in the initial synthesis mixture is not indispensable. We discovered, an initially immiscible synthesis method, which can replace the organic solvent based Stöber method to successfully synthesize silica particles with the same size ranges as the original Stöber process without addition of organic solvents. Moreover, this process can be of further value to be extended to synthesis processes of other materials based on the Stöber process.

The present research focuses on the development of porous MgAl-layered double hydroxide microspheres with high sphericity and uniform particle size distribution. This is based on the droplet coagulation technique using alginate biopolymer as a binder. To achieve this, the suspension formulation was systematically optimized based on zeta potential and rheology measurements. The structural, microtextural and porosity characteristics of the MgAl-LDH powder and the corresponding obtained microspheres were investigated by X-ray diffraction, diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy, optical and scanning electron microscopy, N-2 sorption and Hg intrusion characterization techniques. The combination of these techniques allowed us to highlight that this shaping process leads to the production of porous microspheres in which the LDH plate-like particles are held together in a calcium alginate network without altering their structural features. This research opens up new opportunities for the LDH-type materials towards packed bed applications, such as chemical reactors or sorption columns. (C) 2021 Published by Elsevier B.V.

The present work focuses on the hydrothermal synthesis and properties of porous coordination polymers of metal-porphyrin framework (MPF) type, namely, {[Pr-4 (H2TPPS)(3)]center dot 11H(2)O}(n) (UPJS-10), {[Eu/Sm(H2TPPS)]center dot H3O+center dot 16H(2)O}(n) (UPJS-11), and {[Ce-4(H2TPPS)(3)]center dot 11H(2)O}(n) (UPJS-12) (H2TPPS = 4,4',4 '',4'''-(porphyrin-5,10,15,20-tetrayptetrakisbenzenesulfonate(4)). The compounds were characterized using several analytical techniques: infrared spectroscopy, thermogravimetric measurements, elemental analysis, gas adsorption measurements, and single-crystal structure analysis (SXRD). The results of SXRD revealed a three-dimensional open porous framework containing crossing cavities propagating along all crystallographic axes. Coordination of H2TPPS4- ligands with Ln(III) ions leads to the formation of 1D polymeric chains propagating along the c crystallographic axis. Argon sorption measurements at -186 degrees C show that the activated MPFs have apparent BET surface areas of 260 m(2)g(-1) (UPJS-10) and 230 m(2) g(-1) (UPJS-12). Carbon dioxide adsorption isotherms at 0 degrees C show adsorption capacities up to 1 bar of 9.8 wt % for UPJS-10 and 8.6 wt % for UPJS-12. At a temperature of 20 degrees C, the respective CO2 adsorption capacities decreased to 6.95 and 5.99 wt %, respectively. The magnetic properties of UPJS-10 are characterized by the presence of a close-lying nonmagnetic ground singlet and excited doublet states in the electronic spectrum of Pr(III) ions. A much larger energy difference was suggested between the two lowest Kramers doublets of Ce(III) ions in UPJS - 12. Finally, the analysis of X-band EPR spectra revealed the presence of radical spins, which were tentatively assigned to be originating from the porphyrin ligands.

Modification of metal oxides with organophosphonic acids (PAs) provides the ability to control and tailor the surface properties. The metal oxide phosphonic acid bond (M-O-P) is known to be stable under harsh conditions, making PAs a promising candidate for the recovery of metals from complex acidic leachates. The thiol functional group is an excellent regenerable scavenging group for these applications. However, the research on organophosphonic acid grafting with thiol groups is very limited. In this study, four different metal sorbent materials were designed with different thiol surface coverages. An aqueous-based grafting of 3-mercaptopropylphosphonic acid (3MPPA) on mesoporous TiO

Amino-alkylphosphonic acid-grafted TiO

The application of dielectric barrier discharge (DBD) plasma reactors is promising in various environmental and energy processes, but is limited by their low energy yield. In this study, we put a number of stainless steel rings over the inner electrode rod of the DBD reactor to change the local discharge gap and electric field, and we studied the dry reforming performance. At 50 W supplied power, the metal rings mostly have a negative impact on the performance, which we attribute to the non-uniform spatial distribution of the discharges caused by the rings. However, at 30 W supplied power, the energy yield is higher than at 50 W and the placement of the rings improves the performance of the reactor. More rings and with a larger cross-sectional diameter can further improve the performance. The reactor with 20 rings with a 3.2 mm cross-sectional diameter exhibits the best performance in this study. Compared to the reactor without rings, it increases the CO2 conversion from 7% to 16 %, the CH4 conversion from 12% to 23%, and the energy yield from 0.05 mmol/kJ supplied power to 0.1 mmol/kJ (0.19 mmol/kJ if calculated from the plasma power), respectively. The presence of the rings increases the local electric field, the displaced charge and the discharge fraction, and also makes the discharge more stable and with more uniform intensity. It also slightly improves the selectivity to syngas. The performance improvement observed by placing stainless steel rings in this study may also be applicable to other plasma-based processes.

The effect of pore size on plasma catalysis is crucial but still unclear. Studies have shown plasma cannot enter micropores and mesopores, so catalysts for traditional thermocatalysis may not fit plasma catalysis. Here, 3D porous Cu and CuO with different pore sizes were prepared using uniform silica particles (10–2000 nm) as templates, and compared in plasma-catalytic dry reforming. In most cases, the smaller the pore size, the higher the conversion of CH4 and CO2. Large pores reachable by more electrons did not improve the reaction efficiency. We attribute this to the small surface area and large crystallite size, as indicated by N2-sorption, mercury intrusion and XRD. While the smaller pores might not be reachable by electrons, due to the sheath formed in front of them, as predicted by modeling, they can still be reached by radicals formed in the plasma, and ions can even be attracted into these pores. An exception are the samples synthesized from 1 μm silica, which show better performance. We believe this is due to the electric field enhancement for pore sizes close to the Debye length. The performances of CuO and Cu with different pore sizes can provide references for future research on oxide supports and metal components of plasma catalysts.

The titanium dioxide nanocatalyst (TiO2:NC) was fabricated by chemical precipitation method and annealed at different temperatures. The texture parameters was estimated by Barrett–Joyner–Halenda (BJH) and Brunauer–Emmett–Teller (BET) utilizing nitrogen adsorption–desorption data. The crystal phase transition, enhanced crystallinity and increase in crystallite sizes with temperature were studied by using X-ray diffractograms (XRD). Coinciding with an increase in crystallite size supervising annealing temperatures, the surface area of the TiO2:NC decreases. The average grain size as calculated from scanning electron microscopy (SEM) initially decreases with increasing annealing temperature (300 °C), whereas further increase in annealing temperature (600 °C), is accompanied by the increase in grain size. A red shift was observed in the diffuse reflectance spectra (DRS) caused by a decrease in band gap energy with rising annealing temperatures. The chemical composition was examined by using Fourier transform infrared (FTIR) and energy dispersive X-ray (EDX) spectroscopies. All the annealed TiO2:NC samples were used as photocatalysts for the degradation of rhodamine 6G (R6G) under simulated solar light source. The TiO2:NC annealed at 600 °C have a higher degradation rate constant than the other samples.

Plasma (catalysis) reactors are increasingly being used for gas-based chemical conversions, providing an alternative method of energy delivery to the molecules. In this work we explore whether classical concepts such as equilibrium constants, (overall) rate coefficients, and catalysis exist under plasma conditions. We specifically investigate the existence of a so-called partial chemical equilibrium (PCE), and how process parameters and packing properties influence this equilibrium, as well as the overall apparent rate coefficient, for CO2 splitting in a DBD plasma reactor. The results show that a PCE can be reached, and that the position of the equilibrium, in combination with the rate coefficient, greatly depends on the reactor parameters and operating conditions (i.e., power, pressure, and gap size). A higher power, higher pressure, or smaller gap size enhance both the equilibrium constant and the rate coefficient, although they cannot be independently tuned. Inserting a packing material (non-porous SiO2 and ZrO2 spheres) in the reactor reveals interesting gap/material effects, where the type of material dictates the position of the equilibrium and the rate (inhibition) independently. As a result, no apparent synergistic effect or plasma-catalytic behaviour was observed for the non-porous packing materials studied in this reaction. Within the investigated parameters, equilibrium conversions were obtained between 23 and 71%, while the rate coefficient varied between 0.027 s−1 and 0.17 s−1. This method of analysis can provide a more fundamental insight in the overall reaction kinetics of (catalytic) plasma-based gas conversion, in order to be able to distinguish plasma effects from true catalytic enhancement.

Hybrid titania phosphonate materials can demonstrate a high added value as tailored sorption materials. They combine high chemical stability with great structural versatility, given the wide diversity of functional groups that can be incorporated. Hereto, a fundamental understanding of the synthesis strategies influencing the material performance is required. Therefore three porous TiO2 phosphonate hybrid structures with different functional groups (octyl, propyl, and phenyl) were evaluated in a solid-phase extraction application aimed towards solvent separation. The synthesis was performed by mixing bridged diphosphonic acids (DPAs) with Ti(OBu)4 in a water-ethanol mixture at 30 °C, followed by a hydrothermal post-treatment at 120 °C. The materials were characterized by ICP-AES, 31P solid-state CP/MAS NMR, Raman and FTIR spectroscopy, X-ray diffraction, N2-sorption, and transmission electron microscopy. It is shown that the diphosphonic acids are quantitatively incorporated in the hybrid structures, leading to nanosized particles with a complex but uniquely functionalized surface. A study of the pore structure as a function of the incorporated DPA amount showed materials with a maximum BET surface area of 379 m2/g. The alkyl functionalized hybrid titania phosphonates demonstrated excellent and tunable sorption behavior.

Titanium dioxide (TiO2) is a unique material for biosensing applications due to its capability of hosting enzymes. For the first time, we show that TiO2 can accumulate reactive oxygen species (ROS) under daylight irradiation and can support the catalytic cycle of horseradish peroxidase (HRP) without the need of H2O2 to be present in the solution. Phenolic compounds, such as hydroquinone (HQ) and 4-aminophenol (4-AP), were detected amperometrically in flow-injection analysis (FIA) mode via the use of an electrode modified with TiO2 impregnated with HRP. In contrast to the conventional detection scheme, no H2O2 was added to the analyte solution. Basically, the inherited ability of TiO2 to generate reactive oxygen species is used as a strategy to avoid adding H2O2 in the solution during the detection of phenolic compounds. Electron paramagnetic resonance (EPR) spectroscopy indicates the presence of ROS on titania which, in interaction with HRP, initiate the electrocatalysis toward phenolic compounds. The amperometric response to 4-AP was linear in the concentration range between 0.05 and 2 μM. The sensitivity was 0.51 A M–1 cm–2, and the limit of detection (LOD) 26 nM. The proposed sensor design opens new opportunities for the detection of phenolic traces by HRP-based electrochemical biosensors, yet in a more straightforward and sensitive way following green chemistry principles of avoiding the use of reactive and harmful chemical, such as H2O2.

The stability of metal-organic frameworks (MOFs) typically decreases with an increasing number of defects, limiting the number of defects that can be created and limiting catalytic and other applications. Herein, we use a hemilabile (Hl) linker to create up to a maximum of six defects per cluster in UiO-66. We synthesized hemilabile UiO-66 (Hl-UiO-66) using benzene dicarboxylate (BDC) as linker and 4-sulfonatobenzoate (PSBA) as the hemilabile linker. The PSBA acts not only as a modulator to create defects but also as a coligand that enhances the stability of the resulting defective framework. Furthermore, upon a postsynthetic treatment in H2SO4, the average number of defects increases to the optimum of six missing BDC linkers per cluster (three per formula unit), leaving the Zr-nodes on average sixfold coordinated. Remarkably, the thermal stability of the materials further increases upon this treatment. Periodic density functional theory calculations confirm that the hemilabile ligands strengthen this highly defective structure by several stabilizing interactions. Finally, the catalytic activity of the obtained materials is evaluated in the acid-catalyzed isomerization of α-pinene oxide. This reaction is particularly sensitive to the Brønsted or Lewis acid sites in the catalyst. In comparison to the pristine UiO-66, which mainly possesses Brønsted acid sites, the Hl-UiO-66 and the postsynthetically treated Hl-UiO-66 structures exhibited a higher Lewis acidity and an enhanced activity and selectivity. This is further explored by CD3CN spectroscopic sorption experiments. We have shown that by tuning the number of defects in UiO-66 using PSBA as the hemilabile linker, one can achieve highly defective and stable MOFs and easily control the Brønsted to Lewis acid ratio in the materials and thus their catalytic activity and selectivity. ispartof: JOURNAL OF THE AMERICAN CHEMICAL SOCIETY vol:142 issue:6 pages:3174-3183 ispartof: location:United States status: published

FeCO3 scaling is utilised in a system of closely packed wet Fe-particles (10 μm) to prepare blocks composed of unreacted Fe-cores connected by a ‘cementing matrix of FeCO3 scales’. Within four hours of carbonation at different temperatures (30 °C – 90 °C) and CO2-pressures (1 barg–20 barg), a compressive strength of up to 160 MPa, and a siderite (FeCO3) content of up to 28 % is observed. Typical rhombohedral and atypical needle-shaped FeCO3 crystal morphologies are observed. The dependence of phase composition/morphologies on reaction conditions/processes is discussed. This study is proposed as a prelude towards utilisation of Fe-rich industrial wastes for cementation.

Despite the intensive research on protein adsorption in mesoporous materials, the effect of (de)hydration and confinement on the adsorbed protein's stability and activity is poorly understood. In this paper, we study the effect of differences in structural features (pore size) and drying time on the adsorption and structural stability of horse heart myoglobin (hhMb) on mesoporous titanium dioxide. Infrared spectroscopy (DRIFT) and thermal analysis (TGA) coupled to a quadrupole mass spectrometer (TGA-MS) were used to evaluate the impact of the confinement in different pores and hydration on the myoglobin secondary structure. Electron paramagnetic spectroscopy (EPR) was applied to identify the changes in the heme and its close surrounding. The peroxidase-like activity of myoglobin toward 2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) in the presence of hydrogen peroxide allowed us to detect changes in the protein activity after adsorption in pores with different sizes and drying for different periods of time. The results show a clear effect of the pore size and drying time on the secondary structure of hhMb, which is confirmed by differences induced in the catalytic activity of the adsorbed proteins. Therefore, we recommend evaluating the effect of both hydration and confinement in future applications involving biomolecule adsorption in porous matrices. We are grateful to Guy Reggers (University of Hasselt) for performing the TGA-MS analysis and to Nick Gys (VITO) for measuring the zeta potential of MT8 and MT17. This work was supported by the Research Foundation-Flanders (FWO) (Grant G.0687.13) and the University of Antwerp (GOA-BOF project 28312).

Selective oxidation of methane in a micro fixed-bed reactor by using aqueous H2O2 solution as oxidant was studied. Sub-micrometer sized crystals of HZSM-5 and silicalite-1 with Fe contents below 10 ppm were synthesized. Different methods were used to introduce iron to produce Fe/ZSM-5 zeolites with similar but defined Fe contents. Commercial ZSM-5 with trace amount (175 ppm) of Fe impurity showed considerable methane conversion while over the own nearly Fe-free HZSM-5 no conversion could be measured. Fe/ZSM-5 catalysts prepared by different methods starting from the own nearly Fe-free HZSM-5 showed similar methane conversions and catalysts based on Fe(II) as the precursor exhibited a better performance with regard to retarding over-oxidation. The productivities of oxygenates were enhanced more than two orders of magnitude while at the same time obtaining high turnover frequencies (TOFs) of 303 h−1. A methane conversion as high as 23.5% together with oxygenates selectivity of 90.1% was reached. In contrast to Fe/ZSM-5, Fe/silicalite-1, prepared from Fe-free silicalite-1 by activation via the same post-synthetic preparation methods that were also used to prepare Fe/ZSM-5 and having similar Fe contents, never led to an active catalyst.

Low to negative cost fine industrial metallic iron-rich waste powders are available in large amounts all over the world and are currently often landfilled. The goal of this paper is to investigate the applicability of such waste powders as raw materials for a recently developed hydrothermal hydrogen gas production method, optimised for pure metallic iron powder and operating at a mild hydrothermal temperature of 160 degrees C for 16 h. The influence of several metallic, oxide and salt compounds of elements (M) that are commonly present in metallic iron-rich powder wastes was systematically investigated for two concentration levels, (M:Fe)(low) and (M:Fe)(high). The kinetics of hydrogen gas formation was measured during reaction and the obtained solid residues were analysed. This work shows that the oxidation of metallic iron particles and the consequent H-2 gas production in the investigated hydrothermal reaction system were inhibited through three main effects by the here studied contaminants, namely passivation of the reaction surface, carbonate precipitation and/or redox effects. On the other side, Ni addition promotes the reaction kinetics and acts as a catalyst. However, an excess of Ni inhibits complete iron oxidation through fast precipitation of Fe3O4 on the metallic iron particle surface, forming a passivation layer. Finally, three industrial iron waste powders were treated according to the same hydrothermal treatment Hydrogen gas formation for an iron-rich foundry sand (IWP-A) was inhibited by the formation of a silicate deposit on the iron particles, while the hydrogen gas production from iron works' waste powders (IWP-B and IWP-C) increased with decreasing particle size of the metallic iron particles in the powder. (C) 2018 Elsevier Ltd. All rights reserved.

The impact of waste composition and morphology on the properties of the mullite microstructure were studied by reaction sintering two types of siliceous waste powders with calcined alum sludge. Stoichiometric mixtures of fly ash or rice husk ash with the alum sludge were shaped into mullite microspheres by droplet coagulation. The mullitization reaction was followed by HT-XRD with a distinct difference in onset temperature. The specific powder composition of fly ash (presence of primary mullite) shifted the onset temperature to higher values as compared to the rice husk ash mixture. After sintering at 1600 degrees C, the mullitization reaction resulted in the same yield for both samples. Although the mullite content in the microspheres was equal, distinct differences on the microstructure could be observed. Reaction sintering of the fly ash mixture resulted in lower total porosity with smaller pore sizes.

Carbonation-cementation and bulk reaction mechanisms are studied in systems containing closely packed mixes of particulate Fe (0) (~10 μm) and Ca(OH)2 (0%, 5%, 10% and 15% w/w of Ca(OH)2) subjected to elevated CO2-pressure (1, 5, 10, and 20 barg) and temperature (30 °C and 60 °C). Solid solutions of (CaxFe1-x)CO3 series minerals are observed through shifting and broadening of XRD-reflections with variations in Ca(OH)2 content, CO2-pressure and temperature. The product morphologies varied from rhombohedral in non-Ca(OH)2 systems, to distorted rhombohedral (at 60 °C) and scalenohedral (at 30 °C) in the systems containing Ca(OH)2. An X-ray diffraction-based interpolation method is developed to discern mixed and end-member carbonates for more accurate bulk phase quantification. Based on these observations, variations in cementation performances are explained. Exceptional formation of an Fe-LDH and a (Ca,Fe)-LDH has also been observed in some systems. Interestingly, these LDH phases were stable even after being exposed to ambient conditions for more than 75 days.

Selective oxidation of methane by using aqueous hydrogen peroxide solution as oxidant was investigated. Colloidal nanosized Cu-Fe-silicalite-1 was prepared and a micro reactor was used to intensify mass transport. It was found that the oxygenate productivity could be enhanced nearly three orders of magnitude while simultaneously ensuring high turn-over-frequencies of some 100h(-1). However, the main product in liquid phase was not methanol, but formic acid. At optimized reaction conditions, a selectivity to formic acid of 96.7% at a methane conversion of 10.3% could be achieved.

A DFT study on the adsorption of a series of phosphonic acids (PAs) on the TiO2 anatase (101) and (001) surfaces was performed. The adsorption energies and geometries of the most stable binding modes were compared to literature data and the effect of the inclusion of dispersion forces in the energy calculations was gauged. As the (101) surface is the most exposed surface of TiO2 anatase, the calculated chemical shifts and vibrational frequencies of PM adsorbed on this surface were compared to experimental 31P and 170 NMR and IR data in order to assign the two possible binding modes (mono- and bidentate) to peaks and bands in these spectra; due to the corrugated nature of anatase (101) tridentate binding is not possible on this surface. Analysis of the calculated and experimental 31P chemical shifts indicates that both monodentate and bidentate binding modes are present. For the reactive (001) surface, the results of the calculations indicate that both bi- and tridentate binding modes result in stable systems. Due to the particular sensitivity of 170 chemical shifts to hydrogen bonding and solvent effects, the model used is insufficient to assign these spectra at present. Comparison of calculated and experimental IR spectra leads to the conclusion that IR spectroscopy is not suitable for the characterization of the different binding modes of the adsorption complexes. All calculations were performed using the Hopper HPC infrastructure at the CalcUA core facility of the University of Antwerp, a division of the Flemish Supercomputer Center VSC, funded by the Hercules Foundation, the Flemish Government (department EWI) and the University of Antwerp. The computational resources and services used in this work were provided by the VSC (Flemish Supercomputer Center), funded by the Research Foundation - Flanders (FWO) and the Flemish Government – department EWI. This research was financially supported by FWO (Fonds Wetenschappelijk Onderzoek) via project GO12712N.

Despite the numerous studies on the adsorption of different proteins onto mesoporous titanium dioxide and indications on the important role of buffer solutions in bioactivity, a systematic study on the impact of the buffer on the protein incorporation into porous substrates is still lacking. We here studied the interaction between a commercial mesoporous TiO2 and three of the most used buffers for protein incorporation, i.e. HEPES, Tris and phosphate buffer. In addition, this paper analyzes the adsorption of horse heart myoglobin (hhMb) onto commercial mesoporous TiO2 as a model system to test the influence of buffers on the protein incorporation behavior in mesoporous TiO2. N2 sorption analysis, FT-IR and TGA/DTG measurements were used to evaluate the interaction between the buffers and the TiO2 surface, and the effect of such an interaction on hhMb adsorption. Cyclic voltammetry (CV) and electron paramagnetic resonance (EPR) were used to detect changes in the microenvironment surrounding the heme. The three buffers show a completely different interaction with the TiO2 surface, which drastically affects the adsorption of myoglobin as well as its structure and electrochemical activity. Therefore, special attention is required while choosing the buffer medium to avoid misguided evaluation of protein adsorption on mesoporous TiO2.

Hybrid materials are being developed to add organic functionalities to inorganic materials. Here, titanium dioxide is modified with organophosphonic acids (PAs). In several applications, the surface properties of the material play a key role in their performance (e.g. separation, sorption, catalysis). Hence, the surface properties of these materials need to be specifically adjusted to meet the requirements of each application (e.g. in membrane separation or chromatography). As the synthesis conditions have an important influence on the obtained surface properties, it is necessary to understand the impact and differences introduced by altering synthesis conditions. Different solvents are being applied for modification, but a comparative study of the impact of this change in environments is missing in literature. Therefore, our aim is to study the impact of concentration, temperature and pH in water and toluene on the properties of TiO 2 modified with propylphosphonic acid (3PA). By combining complementary techniques (DRIFT, TGA and 31 P/CP MAS NMR), clear differences induced by the solvent can be found. Moreover, in toluene a lower concentration of 3PA is required to obtain closed packed monolayers than in water. Furthermore, both solvent and concentration are influencing the modification degree and binding type formed on the surface. Moreover, only in water, next to the concentration, also the temperature and pH have a strong impact on the binding type of 3PA. A clear difference in thermal stability of 70 °C was found between both binding types.

The paper reports the observation that siderite (FeCO3 mineral) cementation occurs when compacted Fe-powder (10 µm in this study) is subjected to aqueous carbonation. It is further shown that the siderite contents of the reaction products vary based on the temperature and the CO2-pressure conditions under which they are carbonated. Using SEM-SE observations, two different types of morphologies of siderite crystals are observed based on the temperature are which the aqueous carbonation of iron is performed. The XRD-Rietveld observations and the SEM-SE observations are combined to infer that dendritic Fe-oxide crystals are formed away from the Fe surfaces, and that the siderite crystals grow as scales at the carbonating Fe surfaces. The concurrence of the variation in the siderite content and compressive strength is observed based on XRD-Rietveld analysis. The results of XRD-Rietveld analysis and MIP are combined to show that pore filling and refinement may not be a suitable indicator of compressive strength in such systems.

Plasma catalysis, a promising technology for conversion of CO2 into value-added chemicals near room temperature, is gaining increasing interest. A dielectric barrier discharge (DBD) plasma has attracted attention due to its simple design and operation at near ambient conditions, ease to implement catalysts in the plasma zone and upscaling ability to industrial applications. To improve its main drawbacks, being relatively low conversion and energy efficiency, a packing material is used in the plasma discharge zone of the reactor, sometimes decorated by a catalytic material. Nevertheless, the extent to which different properties of the packing material influence plasma performance is still largely unexplored and unknown. In this study, the particular effect of synthesis induced differences in the morphology of a TiO2 shell covering a SiO2 core packing material on the plasma conversion of CO2 is studied. TiO2 has been successfully deposited around 1.6–1.8 mm sized SiO2 spheres by means of spray coating, starting from aqueous citratoperoxotitanate(IV) precursors. Parameters such as concentration of the Ti(IV) precursor solutions and addition of a binder were found to affect the shells’ properties and surface morphology and to have a major impact on the CO2 conversion in a packed bed DBD plasma reactor. Core-shell SiO2@TiO2 obtained from 0.25 M citratoperoxotitante(IV) precursors with the addition of a LUDOX binder showed the highest CO2 conversion 37.7% (at a space time of 70 s corresponding to an energy efficiency of 2%) and the highest energy efficiency of 4.8% (at a space time of 2.5 s corresponding to a conversion of 3%).

Plasma reactors are interesting for gas-based chemical conversion but the fundamental relation between the plasma chemistry and selected conditions remains poorly understood. Apparent kinetic parameters for the loss and formation processes of individual components of gas conversion processes, can however be extracted by performing experiments in an extended residence time range (2–75 s) and fitting the gas composition to a first-order kinetic model of the evolution towards partial chemical equilibrium (PCE). We specifically investigated the differences in kinetic characteristics and PCE state of the CO2 dissociation and CH4 reforming reactions in a dielectric barrier discharge reactor (DBD), how these are mutually affected when combining both gases in the dry reforming of methane (DRM) reaction, and how they change when a packing material (non-porous SiO2) is added to the reactor. We find that CO2 dissociation is characterized by a comparatively high reaction rate of 0.120 s−1 compared to CH4 reforming at 0.041 s−1; whereas CH4 reforming reaches higher equilibrium conversions, 82% compared to 53.6% for CO2 dissociation. Combining both feed gases makes the DRM reaction to proceed at a relatively high rate (0.088 s−1), and high conversion (75.4%) compared to CO2 dissociation, through accessing new chemical pathways between the products of CO2 and CH4. The addition of the packing material can also distinctly influence the conversion rate and position of the equilibrium, but its precise effect depends strongly on the gas composition. Comparing different CO2:CH4 ratios reveals the delicate balance of the combined chemistry. CO2 drives the loss reactions in DRM, whereas CH4 in the mixture suppresses back reactions. As a result, our methodology provides some of the insight necessary to systematically tune the conversion process.

Amphiphilic Grignard modified ceramic nanofiltration membranes have been demonstrated to perform well for a wide range of solvents in organic solvent nanofiltration (OSN). The purpose of this study is to obtain a better understanding of the influence of the solvent-membrane-solute interactions governing the OSN membrane performance. This was achieved by performing an extensive retention study on two types of Grignard functionalised membranes, in many different solvents with a wide variety of polarity, and choosing three PEG molecules and polystyrene as solutes, all with almost the same size but different polarities. To unravel the transport mechanism properly, also the pressure effect on flux and retentions was thoroughly investigated. The retention results showed in general a very different behavior in different ranges of solvent polarity: at low solvent polarity, retentions are relatively low, varying with pressure and solvent polarity; at high solvent polarity, retentions are relatively high, and independent of pressure and solvent polarity. The Spiegler-Kedem theory, taking into account both diffusion and convection transport mechanisms, appears to be a very good basis for a fundamental explanation of all results. This knowledge shows also how membrane-solvent-solute interactions can be manipulated to enhance the membrane performance.

Immobilization of redox proteins on electrode surfaces is of special interest for mechanistic studies and applications, because of the well-controlled redox state of protein molecules at a polarized electrode and fast electron-transfer kinetics that are free from diffusion limitation. Here, bis-organosilane [1,2-bis(trimethoxysilyl)ethane] was used as a fresh solution in a pH 7 phosphate buffer without the use of any organic solvent, sol-gel, or mesoporous bulk matrix. A short aging period of 30 min before deposition on the electrodes was optimal for the immobilization of proteins. Three redox proteins (cytochrome c, neuroglobin, and GLB-12) were confined to the gold surface of electrodes with high coverages and stabilities, indicating that the suggested technique is simple, efficient, and generic in nature.

In the expansive world of porous hybrid materials, a category of materials that has been rather less explored than others and is gaining attention in development is the porous metal phosphonates. They offer promising features towards applications which demand control over the inorganic–organic network and interface, which is critical for adsorption, catalysis and functional devices and technology. The need to establish a rationale for new synthesis approaches to make these materials in a controlled manner is by itself an important motivation for material chemists. In this review, we highlight the various synthetic strategies exploited, discussing various metal phosphonate systems and how they influence the properties of porous metal phosphonates. We discuss porous metal phosphonate systems based on transition metals with an emphasis on addressing challenges with tetravalent metals. Finally, this review provides a brief description of some key areas of application that are ideally suited for porous metal phosphonates.

Exploitation of engineered nanomaterials with unique properties has been dynamically growing in numerous fields, including the agricultural sector. Due to the increasing resistance of phytopathogenic microbes, human control over various plant pathogens in crop production is a big challenge and requires the development of novel antimicrobial materials. Photocatalytic active nanomaterials could offer an alternative solution to suppress the plant pathogens. In this work, titanium dioxide nanoparticles (TiO2 NPs) with high photocatalytic activity were synthesized by hydrothermal post-treatment of amorphous titania at different temperatures (250 &deg, C or 310 &deg, C) without using any additives or doping agents. The obtained samples were investigated through X-ray diffraction, N2-sorption measurements, diffuse reflectance UV-Vis spectroscopy, transmission electron microscopy, electron paramagnetic resonance spectroscopy, and X-ray photoelectron spectroscopy. The applied hydrothermal treatment led to the formation of TiO2 nanocrystallites with a predominant anatase crystal phase, with increasing crystallinity and crystallite size by prolonging treatment time. The photocatalytic activity of the TiO2 NPs was tested for the photo-degradation of phenol and applied for the inactivation of various plant pathogens such as Erwinia amylovora, Xanthomonas arboricola pv. juglandis, Pseudomonas syringae pv. tomato and Allorhizobium vitis. The studied bacteria showed different susceptibilities, their living cell numbers were quickly and remarkably reduced by UV-A-irradiated TiO2 NPs. The effectiveness of the most active sample prepared at 310 &deg, C was much higher than that of commercial P25 TiO2. We found that fine-tuning of the structural properties by modulating the time and temperature of the hydrothermal treatment influenced the photocatalytic properties of the TiO2 NPs considerably. This work provides valuable information to the development of TiO2-based antimicrobial photocatalysts.

This work proposes to use core-shell structured spheres to evaluate whether it allows to individually optimize bulk and surface effects of a packing material, in order to optimize conversion and energy efficiency. Different core-shell materials have been prepared by spray coating, using dense spheres (as core) and powders (as shell) of SiO2, Al2O3, and BaTiO3. The materials are investigated for their performance in CO2 dissociation and compared against a benchmark consisting of a packed-bed reactor with the pure dense spheres, as well as an empty reactor. The results in terms of CO2 conversion and energy efficiency show various interactions between the core and shell material, depending on their combination. Al2O3 was found as the best core material under the applied conditions here, followed by BaTiO3 and SiO2, in agreement with their behaviour for the pure spheres. Applying a thin shell layer on the cores showed equal performance between the different shell materials. Increasing the layer thickness shifts this behaviour, and strong combination effects were observed depending on the specific material. Therefore, this method of core-shell spheres has the potential to allow tuning of the packing properties more closely to the application by designing an optimal combination of core and shell.

A huge variety of template-assisted mesoporous powder syntheses are known in literature, but the conditions are not directly transferable to thin films. The present study discusses the differences and similarities between the titania powder and thin film synthesis for the preparation of mesoporous titania materials by means of evaporation induced self-assembly. Kr adsorption at -186 degrees C is a sufficient method to analyze the porosity of thin films and is traceable to the N-2 adsorption porosity data obtained at -196 degrees C. Next, problems concerning the macroscopic homogeneity of the thin film are discussed as well as the deposition of the porous layer. Finally, the thermal stabilization and calcination process are compared. In contrast to the powder sample, no nanocrystal formation is observed during the thermal stabilization of the thin film. And thus the average pore size of the thin film is independent of the thermal stabilization in the here investigated range and is in all cases 3.4 nm. Furthermore, the thin film synthesis leads to a better organized and more uniform pore structure as compared to the powder synthesis. Similar to the powder synthesis, uncontrolled crystallization during calcination may lead to a structural collapse of the mesostructure. Although the crystal size after calcination is much smaller for thin films, it seems that the critical crystal size for a structural collapse is smaller for the thin films as compared to the powders. The present study facilitates the transition from optimal powder to optimal thin film synthesis conditions, which could be useful for example in the synthesis of membranes with uniform pores starting from much more extended literature on solid powders certainly with respect to synthesis-structural property correlation. (C) 2015 Elsevier B.V. All rights reserved.

This paper demonstrates that the CO2 conversion in a dielectric barrier discharge rises drastically upon addition of Ar or He, and the effect is more pronounced for Ar than for He. The effective CO2 conversion, on the other hand, drops upon addition of Ar or He, which is logical due to the lower CO2 content in the gas mixture, and the same is true for the energy efficiency, because a considerable fraction of the energy is then consumed into ionization/excitation of Ar or He atoms. The higher absolute CO2 conversion upon addition of Ar or He can be explained by studying in detail the Lissajous plots and the current profiles. The breakdown voltage is lower in the CO2/Ar and CO2/He mixtures, and the discharge gap is more filled with plasma, which enhances the possibility for CO2 conversion. The rates of electron impact excitation–dissociation of CO2, estimated from the electron densities and mean electron energies, are indeed higher in the CO2/Ar and (to a lower extent) in the CO2/He mixtures, compared to the pure CO2 plasma. Moreover, charge transfer between Ar+ or Ar2+ ions and CO2, followed by electron-ion dissociative recombination of the CO2+ ions, might also contribute to, or even be dominant for the CO2 dissociation. All these effects can explain the higher CO2 conversion, especially upon addition of Ar, but also upon addition of He.

Membrane technology is becoming more important as a low energy separation process that can replace or enhance the efficiency of currently often costly and energy-consuming separation processes. After an introduction on the potential of hybrid materials for membranes, we highlight and categorize the wide diversity of hybrid organic-inorganic membranes. In this review, we focus on the preparation and application of class II hybrid organic-inorganic membranes with mechanically stable inorganic supports. Class II points to the presence of covalent bonds between organic and inorganic moieties. The variety of synthesis approaches applied to prepare such separation layers can be divided into 2 types, i.e. direct coating of a pre-formed hybrid solution, and post-synthesis grafting of organic groups. In the last part, we focus on strategies delivering hybrid organic-inorganic membranes that show promise for enhanced molecular separations in gas separation, hydrophilic and organophilic pervaporation and organic solvent nanofiltration. In addition, we will discuss the use of organically modified inorganic RO (reverse osmosis), UF (ultrafiltration) and MF (microfiltration) membranes for ameliorated pressure driven water filtration, membrane contactors, and low-fouling oil/water separation.

In this paper the use of functionalised ceramic nanofiltration membranes in solvent filtration is described. The membranes were grafted using a novel method for surface modification based on Grignard chemistry. Commercially available 1 nm TiO 2 membranes were differently functionalised with a series of alkyl groups (methyl, pentyl, octyl, dodecyl) in order to generate a more hydrophobic membrane surface. The properties of the modified membranes were examined by physico-chemical characterisation (contact angle measurements, micro-ATR/FTIR-spectroscopy) in addition to performance characterisation (flux measurements for solvents ranging from highly polar to non-polar, next to polyethylene glycol retentions in water and polystyrene retentions in acetone). All observations for modified membranes are consistent with the assumed partial replacement of the OH-groups on the membrane surface and the consequent amphiphilic character of the modified membrane surface. The retentions of modified and unmodified membranes in acetone confirm the recent findings in organic solvent nanofiltration (OSN): an increase in the hydrophobicity of the membrane leads to an increase in the retentions. A comparison with reference polymeric membranes shows that the newly developed membranes are a good alternative, having the advantage of the absence of effects of swelling. This new grafting technique for ceramic membranes allows to further explore solvent–membrane–solute interactions in OSN in a controlled way without the extra complexity of swelling.

Despite great efforts in the research area of zeolite nanoparticles and their use in the synthesis of bimodal materials, still little is known about the impact of the synthesis conditions of the zeolite nanoparticles on its own characteristics, and on the properties and the formation mechanism of the final bimodal materials. A zeolite β nanoparticles solution is applied in a mesotemplate-free synthesis method, and the influence of the hydrothermal ageing temperature of the nanoparticles solution on both the zeolitic and porosity characteristics of the final bimodal material has been studied. Transmission electron microscopy in combination with 3-dimensional reconstructions obtained by electron tomography revealed that the zeolite β nanoparticles are connected by neck-like structures, thus creating a wormhole-like mesoporous material. Considering the zeolitic properties, a clear threshold is observed in the synthesis temperature series at 413 K. Below and at this threshold, the biporous materials show no apparent zeolitic characteristics, although these materials exhibit a more condensed and uniform Si–O–Si network in comparison to Al-MCF. Synthesis temperatures above the threshold lead to bimodal structures with defined zeolitic properties. Moreover, the dimensions of the nanoparticles are studied by TEM, revealing an increasing particle size with increasing temperature under the threshold of 413 K, which is in agreement with a sol-mechanism. This mechanism is disturbed after the threshold due to the start of the crystallisation process.

State‐of‐the‐art commercial membranes are made with the sol–gel method. But the pore size is somewhat restricted to control in a reproducible way. Furthermore, the synthesis of uniform pores via the sol–gel method is challenging, and therefore the resulting membranes often exhibit a limited selectivity. In contrast, the template‐assisted method (evaporation‐induced self‐assembly) described herein is able to form defect‐free membranes and thin films with more narrow pore size distributions and thus sharper cutoff curves in a more reproducible way. Moreover, the effect of different templates (Brij 58, Brij 56, Brij 78, Brij 76) and concentrations on the porosity of the titania top layer and separation performance is thoroughly investigated. The pore formation mechanism of the template‐assisted method is discussed. Under the synthesis conditions described herein, the Brij templates act as a separator, whereby the final pore size can be easily controlled by adjusting the amount of template used. Furthermore, the pores obtained with this template‐assisted method are more uniform. Such defect‐free, reproducible small pore ultrafiltration membranes with controllable pore size and narrow pore size distribution can open the path to further process intensification and more sustainable production by separating molecules with a small difference in molecular weight.

We show the possibility to tune the pore size of mesoporous TiO2 templated by non-ionic block copolymers by adding different inorganic acids at well-chosen concentration. The effect of the inorganic anions on both the TiO2 cluster formation and the non-ionic block copolymers micelles is investigated to explain the experimental results.

The hydrothermal, mechanical and chemical stability of various mesoporous materials have been studied in detail, using X-ray diffraction and nitrogen sorption. Pure siliceous nanoporous powders (MCM-41 and SBA-15) are evaluated against their hybrid counterparts; namely 2 types of periodic mesoporous organosilicas (benzene and ethane bridged PMOs) and an organosilane grafted MCM-41 material. In primary tests, the stability of the hybrid materials is found to be superior compared to that of the pure siliceous ones. The stability of the materials was correlated to their hydrophobicity via immersion calorimetry, applied for the first time in this context. Based on these results, a clear correlation between the hydrophobicity of a material and its stability has been revealed. In addition, with 29Si-MAS-NMR and vacuum experiments, the mechanism of the structural deterioration in the three different stability treatments could be unambiguously identified as the hydrolyzation of the siloxane bonds. The homogeneity of the hydrophobic groups throughout the entire network was found to be of great importance, irrespective of the hydrophobic nature at the surface as determined by calorimetric measurements. The results reveal that the most stable material can withstand (a) a pressure of 740 MPa during 5 min, (b) a 2 h stirring in a 2 M NaOH solution and (c) a 3 day steaming treatment at 393 K.

Nanofiltration (NF) membrane fouling by DOM remains a major and poorly understood issue. To acquire a better insight we studied the fouling of the DOM fractions humic acids (HAs) and fulvic acids (FAs), with and without Ca2+, on native and grafted ceramic NF membranes. Grafting with two methods and three different grafting groups allowed to create a range of membranes with a variety of surface chemistries, and a wide range of surface polarity, much broader than ever used in previous studies. A typical polymer (polyamide) NF membrane was included for comparison. All obtained results reveal that membrane fouling is not determined by membrane hydrophilicity/hydrophobicity as a general and sole criterion, but rather on the whole of the surface chemistry determining the amount and strength of the possible foulantmembrane interactions. As a consequence the effect of inorganic ions on the fouling is also dependent on the surface chemistry. Important new insight in the DOM fouling mechanism was acquired, shedding new light on the state-of-the-art knowledge.

In this study the effects of the heating rate and heating time on the formation of crystal-like benzene bridged periodic mesoporous organosilicas (PMOs) are investigated. The time needed to heat up an autoclave during the hydrothermal treatment has shown to be crucial in the synthesis of PMOs, while the total duration of heating gave rise to only minor differences. By choosing a smart heating profile, superior PMO materials can be obtained in a short time. Different heating profiles in a range from one minute to one hour are adopted by microwave equipment and compared with conventional heating methods. The heating rate has a large influence on the porosity characteristics and the uniformity of the obtained particles. Moreover, two new alternative synthetic strategies to adopt the smart heating profile are presented, in order to give some possible solutions for the expensive microwave equipment.

In the field of photocatalytic air purification, the immobilisation of catalyst particles on support surfaces without loss of photon efficiency is an important challenge. Therefore, an immobilisation method involving a one-step suspension coating of pre-synthesised photocatalysts on glass beads was applied. The various benefits are exemplified in the gas phase photodegradation of ethylene. Coating of glass beads is easy, fast, cheap and offers a more efficient alternative to bulk catalyst pellets. Furthermore, this coating procedure allows to use porous, pre-synthesised catalysts to their full potential, as the surface area and morphology of the initial powder is barely altered after coating, in strong contrast to pelletising. With this technique it became possible to study the gas phase photocatalytic activity of commercial titanium dioxide, trititanate nanotubes and mixed phase anatase/trititanate nanotubes in a packed bed reactor towards the degradation of ethylene without changing the catalyst properties. Coating of glass beads with the photocatalyst revealed the superior activity of the as-prepared nanotubes, compared to TiO 2 Aerolyst ® 7710 in gaseous phase.

Zeolitic growth is often absent or occurs in separate phases when synthetic strategies based on the combination of zeolite templates and mesopore templating agents are applied. In this work, zeolitic growth and mesopore formation have been investigated at different temperatures by applying a one-pot templating approach, based on a TS-1 zeolite synthesis whereby part of the microtemplate (tetrapropylammonium hydroxide, TPAOH) is replaced by a mesotemplate (hexadecyltrimethylammonium bromide, CTMABr). Moreover, the synthesis duration and the molar ratio of the microtemplate/mesotemplate have also been studied. The different syntheses clearly show the inherent competitive mechanism between zeolitic growth and mesopore formation. These insights have led to the conclusion that by following a one-pot templating strategy with standard, nonexotic commercial templates, i.e. CTMABr and TPAOH, it is not possible to develop a true hierarchical mesoporous zeolite, meaning a mesoporous siliceous material with highly crystalline zeolitic walls. The resultant materials are instead combined zeolitic/mesoporous composite structures with, however, highly tuneable and controllable porosity characteristics.

Based on a facile one-pot templating synthesis, using a TS-1 zeolite recipe whereby part of the zeolite structure directing agent is replaced by a mesopore templating agent, a trimodal material is formed. The resulting meso-TSM material combines mesoporosity (Ti-MCM-41) with zeolitic features (TS-1) and a unique sheet-like morphology with uniform macroporous voids (macroholes). Moreover, the macrohole formation, mesoporosity and zeolitic properties of the meso-TSM material can be controlled in a straightforward way by adjusting the length of the hydrothermal treatment. This newly developed material may imply great potential for catalytic redox applications and diffusion limitated processes because of its highly tunable character in all three dimensions (micro-, meso- and macroporous scale).

Vanadium silicalite-1 (VS-1) nanoparticles dispersed onto the mesoporous walls of SBA-15 silica have characteristics different from those of the full-grown VS-1. In particular, the vanadium-binding site differs extensively. Here, we monitor the local environment of VO2+ with different electron paramagnetic resonance (EPR) techniques to obtain information about the heterogeneity of the vanadyl sites, the effect of a calcination/reduction cycle, and the subsequent adsorption of 13CO2 and NH3 to the vanadyl sites for both full-grown VS-1 and VS1-SBA15. Furthermore, two-cycle CO2 and NH3 adsorption experiments were performed. While the latter showed no chemisorption of CO2 at 373 K for both materials, clear evidence was found for ligation of CO2 to vanadyl in full-grown VS-1 by the detection of a strong 13C hyperfine value. This strong binding was not detected for the vanadyl centers in VS1-SBA15. Chemisorption of NH3 was detected for all samples both by two-cycle adsorption experiments and by EPR.

A simple solvothermal impregnation method was used to prepare ZnO nanoparticles supported on MCM-41 and SBA-15. X-ray powder diffraction, N2 adsorptiondesorption, Electron Probe Micro Analysis (EPMA), and UVvis spectroscopy were used to characterize the prepared materials. The influence of the ZnO loading of different supports on the structural characteristics and the photocatalytic activity toward degradation of methylene blue in water under ultraviolet irradiation were investigated. Wide angle X-ray diffraction and UVvis Diffuse Reflectance confirmed the existence of ZnO phase. A much smaller influence of impregnation with ethanolic zinc salt solution on the porosity was observed for SBA-15 compared with MCM-41. Finally, the adsorption and photocatalytic activity of the ZnO/mesoporous materials depend on porous characteristics of the support materials.