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A huge focus worldwide is devoted to the production of novel tailored materials to improve electronic devices through sustainable processes. Nowadays, as reagents for the production of metal oxide–carbon composites that could be used in catalysis, sensing, and electrochemical devices, biopolymers are leading candidates. Various TiO2- based nanostructured materials fabricated using different cellulose templates such as nano and microcellulose fibres have been reported previously in the literature. Cellulose, as the most abundant renewable biopolymer, was used as well in our research to control the morphology, porosity, and therefore the properties of the derived composite samples at the nanoscale. Moreover, the tin(IV) oxide has a similar bandgap as already well-studied TiO2, while has not yet reached as wide applicability. In this work, to broaden the research in the field of SnO2 nanostructures, we investigated the properties of cellulose-immobilised SnO2 samples. Additionally, the influence of post-reaction treatment of the samples was investigated. This work focuses on the course of non-hydrolytic sol-gel freeze-drying synthesis in combination with the reductive mineralization of cellulose. Samples' post-treatment was carried out under both inert and atmospheric conditions, at three chosen temperatures (60 °C, 700 °C, and 800 °C). Thin films of the resulting composite samples were prepared and characterised using grazing incidence X-ray diffraction (GIXRD), which overall showed the degree of chemical homogeneity of studied composites. Morphologic and surface geometries were studied by scanning electron microscopy (SEM). Finally, the photocatalytic activity was investigated by photocatalytic degradation with a model micropollutant with previously calculated bandgap values from diffuse reflectance spectroscopy (DRS) measurements.

Kaolinite is a 1:1 clay mineral with the chemical formula Al2O3·2SiO2·2H2O that has a dioctahedral layer structure without charge. Each layer consists of one tetrahedral layer of silicon dioxide and one octahedral layer of aluminum oxide. The high proportion of SiO2 and Al2O3 makes kaolinite an excellent source of aluminosilicates, which is why it is one of the most commonly used natural precursors in the synthesis of geopolymers and zeolites. However, highly ordered crystalline systems are more resistant to alkaline attack than amorphous systems. Therefore, kaolin as a crystalline precursor is often used in its amorphous form - metakaolin, which requires temperature treatment, usually in the range between 600 and 800 °C. In recent years, mechanochemistry has begun to be studied as an alternative to the high-temperature processing (calcining) of kaolin into metakaolin. Due to the reduction of solvent consumption, energy, and faster chemical reactions, mechanochemistry is considered a greener approach in the synthesis of aluminosilicate materials such as geopolymers and zeolites. In this work, the possibility of mechanochemical synthesis of geopolymer-zeolite composite was investigated. The composite synthesis parameters were approximately set to a molar ratio of 1 mol Na2O: 1 mol Al2O3: 2.5 mol SiO2, while the amount of water and the curing temperature of the samples varied. The obtained samples were characterised by XRD, SEM, and ATR- FTIR analysis.

Nowadays, the need for clean energy solutions is rapidly growing. Systems of high interest include versatile nanomaterials capable of energy conversions and storage, whether as photocatalysts, battery materials or transport layers in photovoltaic devices. Such materials need to satisfy multiple criteria, depending on their application, while the method of their synthesis needs to be reproducible, low-cost, green and scalable. Here we report on a solid state synthesis of titanium oxide nanoparticles through spark plasma discharge. We obtained primary particles of sizes as low as 10 nm with a mixed phase composition. Microscopy revealed multiple stages of assembly, stemming from coalescence and aggregation to agglomeration of web like structures. All of these result point out to a highly nanoporous material with an increased number of oxygen defects introduced into the structure which will hopefully serve as a superior electron transporting layer for flexible organic solar cells.

The insulation of buildings and transportation systems has emphasized the necessity to develop advanced materials taking concern to the comfort of modern society ; to noise reduction. A special class of advanced porous materials, i.e. aerogels, can be prepared from inorganic matter, synthetic or natural polymers, as well as inorganic/organic composites and hybrids. Among a variety of different porous materials, aerogels attract much attention due to their excellent properties such as high porosity (>90%), high specific surface area, a variety of macro- and mesopores, etc. The mechanisms of sound absorption are partly different from those of conventional porous absorbers with large macropores (different foams and fibrous materials). The understanding of the acoustic properties of aerogels is far from complete, and experimental results remain dispersed. The list of properties of aerogel materials could be extended to include non-toxic, biocompatible, renewable, and widely available materials. Most importantly, aerogels offer the possibility of functionalization of hydroxyl groups on the polymer backbone [1–3]. In this work, we prepared monolithic cellulose aerogels by the sol-gel procedure followed by their thorough characterization in terms of density, specific surface area and morphology. Samples are shaped to fit an impedance tube (29 mm diameter) to be tested as sound absorbers. Frequency sweeps were performed, and data were recorded from 500 to 6000 Hz. Cellulose concentrations were varied from 4 wt% microcrystalline cellulose (MCC) to 7 wt% MCC, and additionally samples were mixed with sodium sulphate during the preparation procedure to impact pore size, which consequently affects the sound insulation properties, see Figure 1.

Metakaolin is one of the most commonly used precursors for the geopolymer and zeolite preparation due to its high aluminosilicate content, and chemical purity. Generally, metakaolin is obtained by dehydroxylation of kaolinite structure by thermal activation. In this work, we prepared metakaolin through different activation routes, thermal and mechanochemical, respectively. Mechanochemically activated kaolinite (metakaolin) was chosen because it tends to follow the rules of green chemistry, by avoiding energy dissipation when high-temperatures are used. Geopolymers were additionally prepared using the conventional method of alkaline activation of metakaolin with sodium silicate solution. Zeolites were also prepared according to green chemistry rules and by mechanochemical activation instead of the commonly used, hydrothermal one. During the synthesis, both the water amount, and curing temperature were varied. First, the activation reactions were optimized, by monitoring the process and obtaining perfect values for most efficient parameters in terms of time, and other parameters such as temperature and milling speed. Furthermore, the correlation and difference between metakaolin prepared by two different methods were monitored. All prepared samples were thoroughly characterised. For the precursor, we monitored the degree of dihydroxylation, i.e., the degree of activation of the kaolin, or metakaolin preparation. For this purpose, we used the X-ray diffraction method (XRD) as a function of reaction time (milling or thermal activation). Following characterisation was performed using Fourier Transformed Infrared Spectroscopy (FTIR), which again allowed us to gain insight into the dihydroxylation rate and, to confirm characteristic aluminosillicate bonds present in our samples. Finally, we used Scanning Electron Microscopy to monitor microstructure of our samples, precursors and prepared geopolymes/zeolites.

Zinc oxide (ZnO) and titanium oxide (TiO2) are two widely studied metal oxide semiconductors due to their unique optical, electronic, and catalytic properties. These materials have attracted considerable interest in the development of advanced electronic device like sensors, solar cells, and photocatalysts, among other applications. Nanostructured thin films of ZnO and TiO2, with thicknesses ranging from a few to several hundred nanometres, have received increasing attention in recent years due to their exceptional properties arising from the quantum confinement and large surface area-to-volume ratio. These properties include enhanced optical absorption, improved charge transport, and increased reactivity, making them suitable for the above-mentioned various applications. In this work several chemical and physical methods of synthesis were utilized to produce nanostructured thin films, which were thoroughly characterized by SEM, STEM, TEM, AFM, GIXRD, UV- Vis, DLTS and ss-IS, and used in advanced configurations of thin-film based solar cells (perovskite) and as immobilized photocatalysts.

Metakaolin is one of the most researched aluminosilicate minerals due to its simple structure and high (pozzolanic) reactivity. It is often used as a pure precursor in the synthesis of metastable zeolites (geopolymers) and zeolites themselves. However, metakaolin is a dehydroxylated form of kaolin clay and therefore needs high-temperature processing (usually between 600 and 800 °C). Mechanochemical synthesis represents a green approach in modern chemistry due to the reduced consumption of solvents, energy, and faster kinetics. By applying a mechanochemical approach in the synthesis of zeolites, hydrothermal conditions can be avoided, which is eco-friendlier. During the mechanochemical synthesis of zeolite from kaolin, the structure is disturbed through the dehydroxylation (amorphisation) of kaolin due to mechanical grinding, and at the same time, the reaction of alkaline ions and (meta)kaolin occurs, which results in the formation of zeolite and zeolite-like structures. Zeolites as 3D aluminosilicate structures, due to the defined sizes of the entrances of pores and channels, behave like molecular sieves that have very pronounced ion-exchange and adsorption properties. The ability to diffuse cations into the nanopores of the zeolite structure gives the possibility of high ionic conductivity, which opens up the possibility of using zeolites and zeolite-like structures in photovoltaic devices. In this work, the possibility of mechanochemical synthesis of zeolite was investigated, as well as the possibility of performance and applicability of thin-layer configurations of zeolite film in photovoltaic devices. The zeolite synthesis parameters were set to a molar ratio of 1 mol Na2O: 1 mol Al2O3: 2 SiO2, which correspond to zeolite A (LTA). Tape casting was used for the production of thin films, while the amount of water and the curing temperature of the samples was varied. The obtained thin film samples were characterized by XRD, ss-IS, and SEM analysis.

Transparent conductive layers conduct electrical charge in efficient and stable manner while transmit light in the visible part of the spectrum. TCOs are broadly used in optoelectronics, particularly indium doped tin oxide (ITO), at a high production cost. Alternatively, zinc oxide (ZnO) n-type semiconductor can be Al doped (AZO) to improve its electrical properties. AZO films can be derived by various chemical and physical methods of deposition, for example by DC or RF magnetron sputtering commonly yielding uniform films with sufficient conductivity and transparency, with disadvantageous requirements for high vacuum and thermal post-processing MS grown AZO thin films greatly depend on the deposition parameters used during magnetron sputtering ; there is no consensus on how to prepare AZO films using MS. We investigated the films derived by DC MS (from two targets: ZnO and Al with individual power variation and subsequent thermal treatment) using various methods (GID, GISAXS, FEG-SEM, AFM, Raman, UV-VIS, contact angle, solid state impedance spectroscopy) It was shown, that for a deposition type, power and temperature play a crucial role on the resulting properties of prepared AZO films. We think that observed course of deposition and derivative parameters are the consequence of interplay of parameters, all of which are related with domain size. Each individual sample series can be described between extremes being: Al doped ZnO structure with inhomogeneous distribution of residual Al in the material at lower deposition powers and with more structurally disrupted ZnO with more homogeneous Al distribution facilitating better functionality.

Geopolymers or inorganic polymers, initially reported by Davidovits, are generally synthesized by exposing aluminosilicate precursor powders to alkaline silicate solution or phosphoric acid solution under ambient or slightly increased temperature. Despite phosphorus geopolymers have been known for almost as long as alkaline geopolymers and despite the properties of phosphate geopolymers such as better acid- resistant, thermal and dielectric behaviour surpass the properties of their alkaline analogues, phosphate geopolymers still have not matched scientific attention and industrial application comparable to their alkaline analogues. One of the reasons is certainly the use of more expensive phosphoric acid compared to alkaline sodium silicate solution. Here we conducted a synthesis and structural characterization (XRD, ATR-FTIR, TG/DTG/DTA) of phosphorus geopolymer derived from metakaolin and phosphoric acid solution, with the aim of high- tech application of phosphorus geopolymers in electronic devices. According to the available literature, the main parameter in reaction for phosphate-based geopolymers is the Al:P atomic ratio with optimal value of 1. Therefore, in this work, atomic ratio Al:P is set to approximately 1 and the water-to-binder ratio, as a measure of workability of geopolymer paste, is set to 0.5.

Squaraine dyes are a class of electron-donating (p- type) organic molecules, which when blended with appropriate electron acceptors, form bulk heterojunction active layers in small molecule donor organic solar cells (SMD-OSCs). Their thermal and potochemical stability, high utilization of the solar spectrum that extends into the NIR region and ease of synthesis make them excellent candidates for the fabrication of cost efficient, flexible and large area solar panels. In this work, we present squaraine (SQ) donor and fullerene (PC71BM) acceptor solar cells composed from 2, 4-Bis[4-(N, N-diisobutylamino)-2, 6- dihydroxyphenyl] squaraine dye (DIB- SQ). The DIB-SQ wassynthesized using a novel, improved and eco-friendly procedure. Model solar cells of DIB-SQ:PCBM in a ratio of 1:3 were subjected to an extensive optimization through solvent selection (chlorobenzene, chloroform and various mixtures of the two solvents) and spin coating parameters in an ITO/ZnO/SQ:PC71BM/MoO3/Ag inverted structure. Through the course of optimization, the magnitude of influence of certain parameters was elucidated. UV-Vis absorption, recorded on both solutions and thin films, confirmed major differences in absorption behavior for compounds dissolved in different solvents and was further utilized to indicate the degree of SQ dispersion throughout the PC71BM matrix. Solar cells were electrically characterized by means of light intensity dependence measurements, which in combination with extended J/V and EQE measurements gave an insight as to which charge recombination mechanism is dominant in the devices. . Furthermore when this was put in context with morphological studies, i.e. AFM (atomic force microscopy) and TEM (transmission electron microscopy) the influence of processing solvent, spin coating parameters and post process treatment on the morphology and size domains of SQ in BHJ configuration was further clarified and correlated very well to JSC, VOC, FF and PCE. The results gave significant insight on the overall methodology of optimizing new squaraine derivatives for photovoltaic application.

Alkali-activated aluminosilicates or so-called geopolymers (GP) have well cross-linked, 3D, fully polymerized aluminosilicate networks. In terms of pores, following properties could vary, and the most studied cations are potassium, sodium and even lithium. GPs are nowadays enforced as alternatives to concrete materials since their preparation minimally contributes to the energy and environmental problems worldwide. In particular, GPs give rise to new approach that could also boost energy savings. A particularly neat contribution in the overlapping fields of construction and energy materials could arise from the production of GP in the form of a paste that can be further developed into thin films. Such conductive and transparent thin-films could broaden the range of applicability in photovoltaic devices from horizontal mounting only to vertical mounting as well. In this work, we focus on chemical and (micro)structural changes occurring during the mullite-based geopolymer curing. Several factors influence changes, such as Al-to- Si ratio in the precursors and curing temperature. With this in mind, we study the conditions behind the geopolymerisation to obtain optimized samples characterised by XRD, DTA-TGA, FTIR, SEM and IS. Particular attention was paid to the NMR study of the evolution of the GP system as a function of curing temperature. Obtained results allowed a better understanding of the influence of chemical composition and homogeneity of constituents on the following structural, microstructural and electrical characteristics of studied samples. We have also demonstrated an interesting development involving a shift from relatively porous bulk to thin-film configuration, in order to spread the applicability of geopolymers for vertical facade photovoltaic systems.

Recent advantages in ability to prepare materials with their constituting domains in the nanometre range, surely proved beneficial for plethora of semiconducting oxides [1]. Among various systems, ceria nanoparticle having greater surface and pore exposure proved efficient for gas sensing [2]. Here we demonstrate a simple one pot solvothermal synthesis, to derive powders that can be used for room temperature humidity sensing. All samples were broadly characterized using structural (PXRD, GIXRD), morphological (SEM, AFM) and electrical (solid state impedance spectroscopy) methods in a wide range of temperature, frequency and humidity conditions. Initial powders show monophasic crystalline ceria in form of slightly agglomerated spherical particles. Using dry powders, we prepared intermediate slurries and thin-films were tape cast thereof. The thin-films display depth profiling homogeneity and low-roughness. For the electrical characterisation different measurement setups were used employing surface geometry and cross-section geometry. Interestingly, from the impedance spectroscopy it is possible to confirm that the electrical properties are governed by the initial composition and by the film thickness. Derivatively the same processes govern the humidity sensing properties. Under controlled humidity, the shape of the conductivity spectrum remains the same. The relaxation is slow, as the thickness of the pellet slows down the return of conductivity values. Evidently, the thin-film thickness impacts the shape of spectra for surface measurement setup. Consequently, the surface measurement setup proved to be more sensitive to humidity changes.

Ordinary Portland Cement (OPC) is currently the predominant building material in the construction industry, which heavily affecs the environment in series of ways. It would be great to replace OPC with a cheap and reliable material with less pronounced environmental impact. Hence, geopolymers are nowadays considered as the third generation of cements due to their sustainability. Specifically, a much lower CO2 footprint is presented which significantly benefits mitigation of environmental issues. In this work, we focused on chemical and (micro)structural changes that occur during the curing of (pre)mullite-based geopolymers. The influence of various factors was tested, such as the type of ions present in the activation solution and presence of additives for acgieveing desired properties of the composite. Moreover, samples were prepared in bulk and thin- film configuration which were further characterized by DTA-TGA, XRD, SEM, solid state NMR and SS-IS. Particular attention was devoted to improving conductivity by adding various conductive polymers to the geopolymer matrix. Obtained results enabled a better understanding of the patway towards desired properties. A challenging shift from relatively porous bulk to thin-films is presented, broadening the applicability of geopolymers to vertically mounted solar-cells.

A recent investigation of doped ceria catalyst, as well as advanced synthesis methods of ceria catalyst support will be presented. First, the optimization of the hydrothermal synthesis process in order to obtain as small crystallites as possible, as well as testing of the catalytic activity of the prepared nanocatalysts will be described. Then, the properties of ceria doped with various transition metal ions will be presented, after which the focus will be on ceria doped with manganese and copper, which have proven to be the most effective catalysts. Particularly, crystal phases and distribution of manganese, grain growth kinetics, properties and catalytic activity of manganese doped hydrothermally derived ceria, as well as doping levels, thermal stability, properties and catalytic activity of copper doped hydrothermally derived ceria will be presented. Other synthesis procedures such as sol- gel and mechanochemical synthesis will be also presented, as well as the use of doped ceria for other purposes such as UV filter, with focus on cell toxicity, and humidity sensing thin films. Finally, several possible directions of research in the field of synthesis, utilization and properties of ceria and doped ceria nanomaterials will be proposed.

Phosphate-based geopolymers (PGP) are a new type of geopolymers that have recently been studied due to the unresolved formation mechanism, as-achieved (micro)structure and possible applications. Thanks to their non-alkaline environment, PGPs have many advantages over alkaline analogues such as lack of efflorescence and better thermal properties. PGPs resemble to human bones and teeth (whose main constituents are calcium phosphates) stressing out their biocompatible application. PGP are usually obtained by mixing an aluminosilicate precursor with an acidic source of phosphate. In this work, we investigated the feasibility of preparing porous PGP from metakaolin and phosphoric acid via replica shaping. Polyurethane (PU) template was infiltrated by the geopolymer paste until a homogeneous green body was achieved. Green bodies were cured in a sealed vessel at 60 ℃ for 24 h in order to solidify their shape, while thereafter porous geopolymer ceramics were obtained by heat treatment to 600 °C at a rate of 1 ℃ min-1 enabling PU burnout. Samples were characterized through their porosity and morphology (SEM and adsorption behaviour) and chemical structure (XRD and ATR-FTIR). Consequently, with all of the aforementioned advantages, PGPs porous bodies were shown worthy of further investigation for fostering biomedical application.

In fields such as sensing, catalysis, and optoelectronics, it is crucial to find a way to design and fabricate nanocomposites based on semiconducting oxides with improved functional performances. In this context, SnO2 is interesting material, as it is an earth-abundant and widely used semiconductor with a bandgap of 3.6 eV and is known as a part of the transparent conductive oxide (TCO) family used in solar cells. The raw materials required for SnO2 are affordable, thus fostering continuous interest in exploring synthetic routes to SnO2 nanocrystals and nanostructures, including flame pyrolysis, thermal evaporation, hydrothermal synthesis, and various sol-gel methods. In this work, we report on a novel synthesis approach and combination of different methods to characterize SnO2 nanoparticles and nanostructured thin-films in order to control size and morphology through variation of reaction conditions. The samples prepared in the form of bulk and films with diverse morphology were thoroughly (micro)structurally characterized using X-ray diffraction along with AFM and SEM. In view of the potential application of prepared films as a layer in solar cells, the electrical characterization was carried out using Solid-State Impedance Spectroscopy (SS-IS) in a wide range of temperatures and frequencies. The obtained results show a high degree of chemical and structural homogeneity, see Fig. 1. An attempt was made to elucidate the processes behind the formation and growth of nanostructures as a function of the reaction settings. Moreover, the correlation between the (micro)structure and electrical features of prepared materials is discussed in detail. We seek to better control the SnO2 surface properties, including thin-film quality and homogeneity to facilitate charge transfer and mitigate recombination.

Geopolymers are nowadays considered as the third generation of concrete due to their sustainability in the preparation of cement. Specifically, a much lower environmental footprint is present which significantly reduces CO2 emission and helps in terms of resolving environmental issues worldwide. Certain contributions in the overlapping area of construction and energy materials could arise from preparing geopolymers in the form of a paste, which is then further developed into thin-films. In this work, we focused on chemical and (micro)structural changes that occur during the curing of (pre)mullite-based geopolymers. The influence of various factors was tested, such as the presence of ions in the activation solution and presence of additives for acgieveing desired properties of the composite. Therefore, we prepared samples in bulk and thin- film configuration which were characterized by DTA-TGA, XRD, SEM, MAS NMR and SS-IS. Particular attention was devoted to improving conductivity by adding various conductive polymers to the geopolymer matrix. Obtained results enabled a better understanding of the patway towards desired properties. We present a challenging shift from relatively porous bulk to thin-films, broadening the applicability of geopolymers to vertically mounted solar-cells.

By a simple electrochemical etching process, it is possible to anodize titanium substrate and grow ordered vertically aligned arrays of titanium oxide nanotubes. Titanium oxide is a well know and widely used semiconductor, whereas achieving titania in such nanostructured arrays significantly boosts the materials performance. Just by varying synthesis parameters like pH, reaction time, electrolyte, etc. the morphology and thereof functional properties can be easily modified and controlled to an extent. In this work we examined the effect of reaction temperature during the anodization process, ranging from 4°C, 25°C to 60 °C. Samples were examined by grazing incidence X-ray diffraction (GIXRD), scanning electron (SEM) and atomic force (AFM) microscopy, diffuse reflectance spectroscopy (DRS), to define the critical structural, microstructural, optical and surface properties of derived and modified titania films. The effect of the applied temperature was fairly obvious on the morphology of the samples. The appearance varied from fully ordered and well defined nanotubes to poorly grown tubular nanoporous surface. Also for the achieved nanotubes different circumferences and wall thicknesses were observed. Due to the high specific surfaces of the films, they were tested as immobilized photocatalysts for the degradation of waste pharmaceuticals. They have proven effective.

Perovskite solar cells (PSCs) have attracted much research interest due to their advantageous photovoltaic performance. Their properties include for example high carrier mobility, wide optical absorption range, and high power conversion efficiency (PCE). In commonly used planar PSCs, the perovskite layer is sandwiched between the electron and hole transport layers (ETL and HTL). Usually, various inorganic metal oxides, such as TiO2, ZnO, and SnO2, are used as ETLs in PSCs. TiO2, the most studied ETL material, can be fabricated by various methods to produce the final titania layer with different shapes and morphology. For advantageous nanostructured titania, a simple and cheap preparation procedure, by electrochemical oxidation of Ti-foil or a Ti- film yields a high-quality dense array of vertically aligned titania nanotubes. Here we identified that the properties of the titanium substrate are important for the final properties of the ETL, and thus for the solar cell itself. In this work, the synthesis of TiO2 nanotubes by the anodization method is reported, as well as the influence of the (pre)treatment conditions on the resulting samples. We compare the TiO2 nanotubes prepared by electrochemical oxidation of titanium- foils and Ti-film generated by magnetron sputtering on glass substrates. The samples were prepared by pretreating the substrates in different atmospheres and at different temperatures, which provided better insight into the resulting shape and length of the prepared nanotubes, as well as their subsequent features. In the microscopy results we describe the morphology of the titania nanostructures obtained by anodization process. Different methods such as grazing incidence X-ray diffraction (GIXRD) and Kelvin probe force microscopy (KPFM) were employed for systematic characterization. Finally, the electrical properties of the samples were investigated using the solid-state impedance spectroscopy (SS-IS) method.

Developing an easy, low cost method of titanium oxide thin film preparation has been of significant importance in the last decade as they show beneficial functional properties such as good transparency, thermally activated conductivity, wide bandgap and low work function making them suitable for photovoltaic devices, transistors, sensors, etc. [1]. Here we report on the potential use of reactive spark ablation, a novel, low cost and clean method, to produce amorphous titanium oxide thin films suitable for optoelectronic applications by fine tuning the deposition parameters. All of the deposited thin films were characterized at synchrotron X-ray diffraction beamline, also by AFM and SEM which confirmed amorphous structural organisation and meso- nanoporous morphology. XPS spectroscopy was used to determine the Ti:O ratio, while optical bandgap and temperature dependent conductivity were obtained by DRS and electrical measurements using an electrometer.

Due to their similarity, geopolymers and zeolites can be classified in the same category of alkali- aluminosilicate materials. It can be said that the main difference and the key parameter for the formation of zeolite are the hydrothermal conditions: elevated temperature/pressure and the amount of available water. Therefore, geopolymers can be considered an amorphous form of zeolite or metastable zeolites. In this research, the possibility of using the so- called "two-step method" for obtaining zeolite through intermediate product of geopolymer was investigated. The main advantage of this route is simple structural manipulation that can be used in a wide range of applications such as the development of dielectric materials, membranes, adsorption and immobilization of heavy metals, building materials, etc. Another advantage of this method is the possibility of making the desired shape of the material by geopolymer synthesis route at atmospheric pressure and temperatures below 80 ℃, which results in the formation of amorphous alkali-aluminosilicate material. Then, in hydrothermal conditions, the surface of the resulting material can be reorganized into an ordered crystalline structure. Metakaolin under the commercial name Metamax (BASF) and various water glasses (Na, Na/K and K) manufactured by Vodní sklo were used to obtain the geopolymer. While in hydrothermal synthesis, the influence of alkali metal oxides and silicon dioxide on the formation of zeolite structures at constant temperature was studied. The obtained samples were characterized by SEM, XRD and FTIR technique.

Iron phosphate-based glasses (IPGs) belong to a family of electronically conducting amorphous materials. Due to the presence of transition metal (TM) ions, e.g. iron, in more than one valence state, the conduction mechanism of small polaron hopping (SPH) is present. These materials are of boundless scientific interest due to their potential application as electrode materials for batteries, electronic circuit elements, etc. Here, we report the effect of the addition of modifiers and network formers on the polaronic transport in binary IP glass. The electrical properties of two glass systems HfO2–B2O3–Fe2O3–P2O5 are studied in detail by Solid State Impedance Spectroscopy (SS-IS) over a wide range of frequencies and temperatures, revealing interesting features behind the polaronic transport. The addition of oxides significantly alters the Fe2+/Fetotal ratio, which directly affects the polaron number density and strongly controls the DC conductivity trends for both series. In addition, we found that short-range polaron dynamics are also under the influence of structural changes. Therefore, we studied them in detail using relatively simple but very informative model-free scaling procedures, namely Summerfield and Sidebottom scaling. Both procedures on the conductivity spectra confirmed the validity of the time-temperature superposition (TTS) principle for all glasses. An attempt to construct a super-master curve revealed that hopping lengths of the polarons also change, and Sidebottom scaling results in a super-master curve. In the next step, the spatial extent of the localized motion of the polarons is correlated with the polaron number density and two distinct regions with low and high polaron concentration glasses are confirmed. The transition between these regions is not only related to the polaron number density, but also to the combination of glass compositions and parameters that have an impact on the polaron motions. The relationship between the structural changes and conductivity mechanism is discussed in detail. The obtained results provide new valuable information about the resulting mixed glass network and its effect on the polaron formation and its dynamics.