Advances in Functional Inorganic Materials Prepared by Wet Chemical Methods

A special issue of Crystals (ISSN 2073-4352). This special issue belongs to the section "Inorganic Crystalline Materials".

Deadline for manuscript submissions: closed (1 May 2021) | Viewed by 34558

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Institute of Chemistry, Faculty of Chemistry and Geosciences, Vilnius University, Naugarduko 24, LT-03225 Vilnius, Lithuania
Interests: functional inorganic materials; mixed metal oxides; inorganic biomaterials; nanomaterials; thin films; ceramics
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Institute of Chemistry, Vilnius University, LT-03225 Vilnius, Lithuania
Interests: multifunctional metal oxides; catalysts; microstructure; physical properties; nanoparticles; nanoclusters; nanocomposites; solid-state chemistry
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Dear Colleagues,

Functional inorganic materials are an indispensable part of innovative technologies, which are essential to the development of many fields of industry. The use of new materials, nanostructures, or multicomponent composites with specific chemical or physical properties promotes technological progress in electronics, optoelectronics, catalysis, biomedicine, and many other areas that are concerned with plenty of aspects of human life. Due to the broad and diverse range of potential applications of functional inorganic materials, the development of superior synthesis pathways, reliable characterization, and a deep understanding of the structure–property relationships in materials are rightfully considered to be fundamentally important scientific issues. Only synergetic efforts of scientists dealing with the synthesis, functionalization, and characterization of materials will lead to the development of future technologies.

The scope of this Special Issue of Crystals, entitled “Advances in Functional Inorganic Materials Prepared by Wet Chemical Methods”, includes, but is not limited to, the preparation routes, characterization, and application of functional inorganic materials, as well as hybrid materials that are important in the fields of electronics, optics, and biomedicine, among others. We would like to invite you to submit your work in the form of an original research article or a review paper related to the investigation of bulk materials, nanomaterials, or thin films.

Dr. Aleksej Zarkov
Dr. Aivaras Kareiva
Dr. Loreta Tamasauskaite-Tamasiunaite
Guest Editors

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Keywords

  • Multifunctional materials
  • Magnetic materials
  • Ferroelectric materials
  • Piezoelectric materials
  • Optical materials
  • Processing routes
  • Ceramics

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Published Papers (11 papers)

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Editorial

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3 pages, 163 KiB  
Editorial
Advances in Functional Inorganic Materials Prepared by Wet Chemical Methods
by Aleksej Zarkov, Aivaras Kareiva and Loreta Tamasauskaite-Tamasiunaite
Crystals 2021, 11(8), 943; https://doi.org/10.3390/cryst11080943 - 13 Aug 2021
Cited by 1 | Viewed by 1457
Abstract
Functional inorganic materials are an indispensable part of innovative technologies, which are essential to the development of many fields of industry [...] Full article

Research

Jump to: Editorial

13 pages, 2721 KiB  
Article
Effect of Poly(Titanium Oxide) on the Viscoelastic and Thermophysical Properties of Interpenetrating Polymer Networks
by Tamara Tsebriienko and Anatoli I. Popov
Crystals 2021, 11(7), 794; https://doi.org/10.3390/cryst11070794 - 7 Jul 2021
Cited by 45 | Viewed by 3440
Abstract
The influence of poly(titanium oxide) obtained using the sol-gel method in 2-hydroxyethyl methacrylate medium on the viscoelastic and thermophysical properties of interpenetrating polymer networks (IPNs) based on cross-linked polyurethane (PU) and poly(hydroxyethyl methacrylate) (PHEMA) was studied. It was found that both the initial [...] Read more.
The influence of poly(titanium oxide) obtained using the sol-gel method in 2-hydroxyethyl methacrylate medium on the viscoelastic and thermophysical properties of interpenetrating polymer networks (IPNs) based on cross-linked polyurethane (PU) and poly(hydroxyethyl methacrylate) (PHEMA) was studied. It was found that both the initial (IPNs) and organo-inorganic interpenetrating polymer networks (OI IPNs) have a two-phase structure by using methods of dynamic mechanical analysis (DMA) and differential scanning calorimetry (DSC). The differential scanning calorimetry methods and scanning electron microscopy (SEM) showed that the presence of poly(titanium oxide) increases the compatibility of the components of IPNs. It was found that an increase in poly(titanium oxide) content leads to a decrease in the intensity of the relaxation maximum for PHEMA phase and an increase in the effective crosslinking density due to the partial grafting of the inorganic component to acrylate. It was shown that the topology of poly(titanium oxide) structure has a significant effect on the relaxation behavior of OI IPNs samples. According to SEM, a uniform distribution of the inorganic component in the polymer matrix is observed without significant aggregation. Full article
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14 pages, 2795 KiB  
Article
Synthesis of Carbon-Supported MnO2 Nanocomposites for Supercapacitors Application
by Jolita Jablonskiene, Dijana Simkunaite, Jurate Vaiciuniene, Giedrius Stalnionis, Audrius Drabavicius, Vitalija Jasulaitiene, Vidas Pakstas, Loreta Tamasauskaite-Tamasiunaite and Eugenijus Norkus
Crystals 2021, 11(7), 784; https://doi.org/10.3390/cryst11070784 - 5 Jul 2021
Cited by 12 | Viewed by 2705
Abstract
In this study, carbon-supported MnO2 nanocomposites have been prepared using the microwave-assisted heating method followed by two different approaches. The MnO2/C nanocomposite, labeled as sample S1, was prepared directly by the microwave-assisted synthesis of mixed KMnO4 and carbon powder [...] Read more.
In this study, carbon-supported MnO2 nanocomposites have been prepared using the microwave-assisted heating method followed by two different approaches. The MnO2/C nanocomposite, labeled as sample S1, was prepared directly by the microwave-assisted synthesis of mixed KMnO4 and carbon powder components. Meanwhile, the other MnO2/C nanocomposite sample labeled as S2 was prepared indirectly via a two-step procedure that involves the microwave-assisted synthesis of mixed KMnO4 and MnSO4 components to generate MnO2 and subsequent secondary microwave heating of synthesized MnO2 species coupled with graphite powder. Field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and inductively coupled plasma optical emission spectroscopy have been used for characterization of MnO2/C nanocomposites morphology, structure, and composition. The electrochemical performance of nanocomposites has been investigated using cyclic voltammetry and galvanostatic charge/discharge measurements in a 1 M Na2SO4 solution. The MnO2/C nanocomposite, prepared indirectly via a two-step procedure, displays substantially enhanced electrochemical characteristics. The high specific capacitance of 980.7 F g−1 has been achieved from cyclic voltammetry measurements, whereas specific capacitance of 949.3 F g−1 at 1 A g−1 has been obtained from galvanostatic charge/discharge test for sample S2. In addition, the specific capacitance retention was 93% after 100 cycles at 20 A g−1, indicating good electrochemical stability. Full article
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10 pages, 2494 KiB  
Article
Characterization of GAGG Doped with Extremely Low Levels of Chromium and Exhibiting Exceptional Intensity of Emission in NIR Region
by Greta Inkrataite, Gerardas Laurinavicius, David Enseling, Aleksej Zarkov, Thomas Jüstel and Ramunas Skaudzius
Crystals 2021, 11(6), 673; https://doi.org/10.3390/cryst11060673 - 11 Jun 2021
Cited by 8 | Viewed by 3943
Abstract
Cerium and chromium co-doped gadolinium aluminum gallium garnets were prepared using sol-gel technique. These compounds potentially can be applied for NIR-LED construction, horticulture and theranostics. Additionally, magnesium and calcium ions were also incorporated into the structure. X-ray diffraction data analysis confirmed the all-cubic [...] Read more.
Cerium and chromium co-doped gadolinium aluminum gallium garnets were prepared using sol-gel technique. These compounds potentially can be applied for NIR-LED construction, horticulture and theranostics. Additionally, magnesium and calcium ions were also incorporated into the structure. X-ray diffraction data analysis confirmed the all-cubic symmetry with an Ia-3d space group, which is appropriate for garnet-type materials. From the characterization of the luminescence properties, it was confirmed that both chromium and cerium emissions could be incorporated. Cerium luminescence was detected under 450 nm excitation, while for chromium emission, 270 nm excitation was used. The emission of chromium ions was exceptionally intense, although it was determined that these compounds are doped only by parts per million of Cr3+ ions. Typically, the emission maxima of chromium ions are located around 650–750 nm in garnet systems. However, in this case, the emission maximum for chromium is measured to be around 790 nm, caused by re-absorption of Cr3+ ions. The main observation of this study is that the switchable emission wavelength in a compound of single phase was obtained, despite the fact that doping with Cr ions was performed in ppm level, causing an intense emission in NIR region. Full article
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22 pages, 9923 KiB  
Article
Hydrothermal Synthesis, Crystal Structure, and Spectroscopic Properties of Pure and Eu3+-Doped NaY[SO4]2 ∙ H2O and Its Anhydrate NaY[SO4]2
by Constantin Buyer, David Enseling, Thomas Jüstel and Thomas Schleid
Crystals 2021, 11(6), 575; https://doi.org/10.3390/cryst11060575 - 21 May 2021
Cited by 8 | Viewed by 3396
Abstract
The water-soluble colorless compound NaY[SO4]2 ∙ H2O was synthesized with wet methods in a Teflon autoclave by adding a mixture of Na2[SO4] and Y2[SO4]3 ∙ 8 H2O [...] Read more.
The water-soluble colorless compound NaY[SO4]2 ∙ H2O was synthesized with wet methods in a Teflon autoclave by adding a mixture of Na2[SO4] and Y2[SO4]3 ∙ 8 H2O to a small amount of water and heating it up to 190 °C. By slow cooling, single crystals could be obtained and the trigonal crystal structure of NaY[SO4]2 ∙ H2O was refined based on X-ray diffraction data in space group P3221 (a = 682.24(5) pm, c = 1270.65(9) pm, Z = 3). After its thermal decomposition starting at 180 °C, the anhydrate NaY[SO4]2 can be obtained with a monoclinic crystal structure refined from powder X-ray diffraction data in space group P21/m (a = 467.697(5) pm, b = 686.380(6) pm, c = 956.597(9) pm, β = 96.8079(5), Z = 2). Both compounds display unique Y3+-cation sites with eightfold oxygen coordination (d(Y–Os = 220–277 pm)) from tetrahedral [SO4]2− anions (d(S–O = 141–151 pm)) and a ninth oxygen ligand from an H2O molecule (d(Y–Ow = 238 pm) in the hydrate case. In both compounds, the Na+ cations are atoms (d(Na–Os = 224–290 pm) from six independent [SO4]2− tetrahedra each. Thermogravimetry and temperature-dependent PXRD experiments were performed as well as IR and Raman spectroscopic studies. Eu3+-doped samples were investigated for their photoluminescence properties in both cases. The quantum yield of the red luminescence for the anhydrate NaY[SO4]2:Eu3+ was found to be almost 20 times higher than the one of the hydrate NaY[SO4]2 ∙ H2O:Eu3+. The anhydrate NaY[SO4]2:Eu3+ exhibits a decay time of about τ1/e = 2.3 µm almost independent of the temperature between 100 and 500 K, while the CIE1931 color coordinates at x = 0.65 and y = 0.35 are very temperature-consistent too. Due to these findings, the anhydrate is suitable as a red emitter in lighting for emissive displays. Full article
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13 pages, 3121 KiB  
Article
Extraction–Pyrolytic Method for TiO2 Polymorphs Production
by Vera Serga, Regina Burve, Aija Krumina, Marina Romanova, Eugene A. Kotomin and Anatoli I. Popov
Crystals 2021, 11(4), 431; https://doi.org/10.3390/cryst11040431 - 16 Apr 2021
Cited by 50 | Viewed by 3607
Abstract
The unique properties and numerous applications of nanocrystalline titanium dioxide (TiO2) are stimulating research on improving the existing and developing new titanium dioxide synthesis methods. In this work, we demonstrate for the first time the possibilities of the extraction–pyrolytic method (EPM) [...] Read more.
The unique properties and numerous applications of nanocrystalline titanium dioxide (TiO2) are stimulating research on improving the existing and developing new titanium dioxide synthesis methods. In this work, we demonstrate for the first time the possibilities of the extraction–pyrolytic method (EPM) for the production of nanocrystalline TiO2 powders. A titanium-containing precursor (extract) was prepared by liquid–liquid extraction using valeric acid C4H9COOH without diluent as an extractant. Simultaneous thermogravimetric analysis and differential scanning calorimetry (TGA–DSC), as well as the Fourier-transform infrared (FTIR) spectroscopy were used to determine the temperature conditions to fabricate TiO2 powders free of organic impurities. The produced materials were also characterized by X-ray diffraction (XRD) analysis and transmission electron microscopy (TEM). The results showed the possibility of the fabrication of storage-stable liquid titanium (IV)-containing precursor, which provided nanocrystalline TiO2 powders. It was established that the EPM permits the production of both monophase (anatase polymorph or rutile polymorph) and biphase (mixed anatase–rutile polymorphs), impurity-free nanocrystalline TiO2 powders. For comparison, TiO2 powders were also produced by the precipitation method. The results presented in this study could serve as a solid basis for further developing the EPM for the cheap and simple production of nanocrystalline TiO2-based materials in the form of doped nanocrystalline powders, thin films, and composite materials. Full article
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22 pages, 7394 KiB  
Article
Synthesis and Characterization of Potent and Safe Ciprofloxacin-Loaded Ag/TiO2/CS Nanohybrid against Mastitis Causing E. coli
by Naheed Zafar, Bushra Uzair, Muhammad Bilal Khan Niazi, Ghufrana Samin, Asma Bano, Nazia Jamil, Waqar-Un-Nisa, Shamaila Sajjad and Farid Menaa
Crystals 2021, 11(3), 319; https://doi.org/10.3390/cryst11030319 - 23 Mar 2021
Cited by 10 | Viewed by 3434
Abstract
To improve the efficacy of existing classes of antibiotics (ciprofloxacin), allow dose reduction, and minimize related toxicity, this study was executed because new target-oriented livestock antimicrobials are greatly needed to battle infections caused by multidrug-resistant (MDR) strains. The present study aims to green [...] Read more.
To improve the efficacy of existing classes of antibiotics (ciprofloxacin), allow dose reduction, and minimize related toxicity, this study was executed because new target-oriented livestock antimicrobials are greatly needed to battle infections caused by multidrug-resistant (MDR) strains. The present study aims to green synthesize a biocompatible nanohybrid of ciprofloxacin (CIP)-Ag/TiO2/chitosan (CS). Silver and titanium nanoparticles were green synthesized using Moringa concanensis leaves extract. The incorporation of silver (Ag) nanoparticles onto the surface of titanium oxide nanoparticles (TiO2NPs) was done by the wet chemical impregnation method, while the encapsulation of chitosan (CS) around Ag/TiO2 conjugated with ciprofloxacin (CIP) was done by the ionic gelation method. The synthesized nanohybrid (CIP-Ag/TiO2/CS) was characterized using standard techniques. The antibacterial potential, killing kinetics, cytotoxicity, drug release profile, and minimum inhibitory concentration (MIC) were determined. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) revealed spherical agglomerated nanoparticles (NPs) of Ag/TiO2 with particle sizes of 47–75 nm, and those of the CIP-Ag/TiO2/CS nanohybrid were in range of 20–80 nm. X-ray diffractometer (XRD) patterns of the hetero system transmitted diffraction peaks of anatase phase of TiO2 and centered cubic metallic Ag crystals. Fourier Transform Infrared spectroscopy (FTIR) confirmed the Ti-O-Ag linkage in the nanohybrid. The zeta potential of CIP-Ag/TiO2/CS nanohybrid was found (67.45 ± 1.8 mV), suggesting stable nanodispersion. The MIC of CIP-Ag/TiO2/CS was 0.0512 μg/mL, which is much lower than the reference value recorded by the global CLSI system (Clinical Laboratory Standards Institute). The CIP-Ag/TiO2/CS nanohybrid was found to be effective against mastitis causing MDR E. coli; killing kinetics showed an excellent reduction of E. coli cells at 6 h of treatment. Flow cytometry further confirmed antibacterial potential by computing 67.87% late apoptosis feature at 6 h of treatment; antibiotic release kinetic revealed a sustained release of CIP. FESEM and TEM confirmed the structural damages in MDR E. coli (multidrug-resistant Escherichia coli). The CIP-Ag/TiO2/CS nanohybrid was found to be biocompatible, as more than 93.08% of bovine mammary gland epithelial cells remained viable. The results provide the biological backing for the development of nanohybrid antibiotics at a lower MIC value to treat infectious diseases of cattle and improve the efficacy of existing classes of antibiotics by conjugation with nanoparticles. Full article
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11 pages, 18741 KiB  
Article
Simple and Acid-Free Hydrothermal Synthesis of Bioactive Glass 58SiO2-33CaO-9P2O5 (wt%)
by Ta Anh Tuan, Elena V. Guseva, Nguyen Anh Tien, Ho Tan Dat and Bui Xuan Vuong
Crystals 2021, 11(3), 283; https://doi.org/10.3390/cryst11030283 - 12 Mar 2021
Cited by 10 | Viewed by 2698
Abstract
The paper focuses on the acid-free hydrothermal process for the synthesis of bioactive glass. The new method avoids the use of harmful acid catalysts, which are usually used in the sol-gel process. On the other hand, the processing time was reduced compared with [...] Read more.
The paper focuses on the acid-free hydrothermal process for the synthesis of bioactive glass. The new method avoids the use of harmful acid catalysts, which are usually used in the sol-gel process. On the other hand, the processing time was reduced compared with the sol-gel method. A well-known ternary bioactive glass 58SiO2-33CaO-9P2O5 (wt%), which has been widely synthesized through the sol-gel method, was selected to apply to this new process. Thermal behavior, textural property, phase composition, morphology, and ionic exchange were investigated by thermal analysis, N2 adsorption/desorption, XRD, FTIR, SEM, and inductively coupled plasma optical emission spectrometry (ICP-OES) analysis. The bioactivity and biocompatibility of synthetic bioactive glass were evaluated by in vitro experiments with a simulated body fluid (SBF) solution and cell culture medium. The obtained results confirmed that the acid-free hydrothermal process is one of the ideal methods for preparing ternary bioactive glass. Full article
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9 pages, 2110 KiB  
Communication
Broadband Detection Based on 2D Bi2Se3/ZnO Nanowire Heterojunction
by Zhi Zeng, Dongbo Wang, Jinzhong Wang, Shujie Jiao, Donghao Liu, Bingke Zhang, Chenchen Zhao, Yangyang Liu, Yaxin Liu, Zhikun Xu, Xuan Fang and Liancheng Zhao
Crystals 2021, 11(2), 169; https://doi.org/10.3390/cryst11020169 - 8 Feb 2021
Cited by 10 | Viewed by 2582
Abstract
The investigation of photodetectors with broadband response and high responsivity is essential. Zinc Oxide (ZnO) nanowire has the potential of application in photodetectors, owing to the great optoelectrical property and good stability in the atmosphere. However, due to a large number of nonradiative [...] Read more.
The investigation of photodetectors with broadband response and high responsivity is essential. Zinc Oxide (ZnO) nanowire has the potential of application in photodetectors, owing to the great optoelectrical property and good stability in the atmosphere. However, due to a large number of nonradiative centers at interface and the capture of surface state electrons, the photocurrent of ZnO based photodetectors is still low. In this work, 2D Bi2Se3/ZnO NWAs heterojunction with type-I band alignment is established. This heterojunction device shows not only an enhanced photoresponsivity of 0.15 A/W at 377 nm three times of the bare ZnO nanowire (0.046 A/W), but also a broadband photoresponse from UV to near infrared region has been achieved. These results indicate that the Bi2Se3/ZnO NWAs type-I heterojunction is an ideal photodetector in broadband detection. Full article
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11 pages, 20121 KiB  
Article
The Synthesis and Characterization of Sol-Gel-Derived SrTiO3-BiMnO3 Solid Solutions
by Dovydas Karoblis, Ramunas Diliautas, Eva Raudonyte-Svirbutaviciene, Kestutis Mazeika, Dalis Baltrunas, Aldona Beganskiene, Aleksej Zarkov and Aivaras Kareiva
Crystals 2020, 10(12), 1125; https://doi.org/10.3390/cryst10121125 - 10 Dec 2020
Cited by 3 | Viewed by 2985
Abstract
In this study, the aqueous sol-gel method was employed for the synthesis of (1−x)SrTiO3-xBiMnO3 solid solutions. Powder X-ray diffraction analysis confirmed the formation of single-phase perovskites with a cubic structure up to x = 0.3. A further increase of the [...] Read more.
In this study, the aqueous sol-gel method was employed for the synthesis of (1−x)SrTiO3-xBiMnO3 solid solutions. Powder X-ray diffraction analysis confirmed the formation of single-phase perovskites with a cubic structure up to x = 0.3. A further increase of the BiMnO3 content led to the formation of a negligible amount of neighboring Mn3O4 impurity, along with the major perovskite phase. Infrared (FT-IR) analysis of the synthesized specimens showed gradual spectral change associated with the superposition effect of Mn-O and Ti-O bond lengths. By introducing BiMnO3 into the SrTiO3 crystal structure, the size of the grains increased drastically, which was confirmed by means of scanning electron microscopy. Magnetization studies revealed that all solid solutions containing the BiMnO3 component can be characterized as paramagnetic materials. It was observed that magnetization values clearly correlate with the chemical composition of powders, and the gradual increase of the BiMnO3 content resulted in noticeably higher magnetization values. Full article
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9 pages, 3852 KiB  
Article
Ga-Substituted Cobalt-Chromium Spinels as Ceramic Pigments Produced by Sol–Gel Synthesis
by Egle Grazenaite, Edita Garskaite, Zivile Stankeviciute, Eva Raudonyte-Svirbutaviciene, Aleksej Zarkov and Aivaras Kareiva
Crystals 2020, 10(12), 1078; https://doi.org/10.3390/cryst10121078 - 25 Nov 2020
Cited by 11 | Viewed by 2671
Abstract
For the first time to the best of our knowledge, cobalt-chromium spinels CoCr2−xGaxO4 with different amounts of gallium (x = 0–2 with a step of 0.5) were synthesized via the aqueous sol–gel route as ceramic pigments. The phase [...] Read more.
For the first time to the best of our knowledge, cobalt-chromium spinels CoCr2−xGaxO4 with different amounts of gallium (x = 0–2 with a step of 0.5) were synthesized via the aqueous sol–gel route as ceramic pigments. The phase composition, crystallite size, morphological features, and color parameters of new compositions and their corresponding ceramic glazes were investigated using XRD, CIELab, SEM, and optical microscopy. It was demonstrated that the formation of single-phase CoCr2−xGaxO4 samples was problematic. Full substitution of Cr3+ by Ga3+ ion in the spinel resulted in the formation of light blue powders, which yielded violetish blue color for the corresponding ceramic glaze. Full article
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