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This work reports the synthesis and characterization of novel zeolite-like indium silicate MS-2 (Minho-Sofia, solid number 2). The structure of this material is analogous to that of the mineral imandrite (Na

Small-pore iron silicate MS-1 (Minho-Sofia, solid number 1) with a 3D porous system, an analogue of the rare mineral imandrite, has been synthesized and characterized. This material is the lowest framework density iron silicate, one of the most siliceous (Si/Fe = 6) iron silicates, the first iron cyclosilicate achieved at hydrothermal conditions, and the only synthetic iron-based member of the lovozerite mineral group.

The demand for more efficient energy storage devices has led to the exponential growth of lithium-ion batteries. To overcome the limitations of these systems in terms of safety and to reduce environmental impact, solid-state technology emerges as a suitable approach. This work reports on a three-component solid polymer electrolyte system based on poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), the ionic liquid 1-butyl-3-methylimidazolium thiocyanate ([BMIM][SCN]), and clinoptilolite zeolite (CPT). The influences of the preparation method and of the dopants on the electrolyte stability, ionic conductivity, and battery performance were studied. The developed electrolytes show an improved room temperature ionic conductivity (1.9 × 10–4 S cm–1), thermal stability (up to 300 °C), and mechanical stability. The corresponding batteries exhibit an outstanding room temperature performance of 160.3 mAh g–1 at a C/15-rate, with a capacity retention of 76% after 50 cycles. These results represent a step forward in a promising technology aiming the widespread implementation of solid-state batteries., FCT (Fundação para a Ciência e Tecnologia) for financial support under the framework of Strategic Funding grants UID/CTM/50025/2021, UID/FIS/04650/2021, UID/EEA/04436/2021 and UID/QUI/0686/2021; and support from FEDER funds through the COMPETE 2020 Programme (projects PTDC/FISMAC/28157/2017 and POCI-01-0145-FEDER-007688). Grants SFRH/BD/140842/2018 (J.C.B.) and SFRH/BPD/121526/2016 (D.M.C) and contracts under the Stimulus of Scientific Employment, Individual Support CEECIND/00833/2017 (R.G.) and 2020.04028 CEECIND (C.M.C.) are acknowledged. Financial support from the Basque Government under the ELKARTEK program, Basque University System Research Groups, IT-1290-19 and the University of the Basque Country (GIU18/197). is also acknowledged

Materials science is increasingly relying on sustainable methods for synthesis of advanced materials. This work demonstrates the first template-free approach for the crystallization of tavorite, LiFePO4(OH), in the form of hollow microspheres and unique core (single crystal) –shell (aggregated particles) cross-like dendrites. The different morphologies have been obtained by hydrothermal synthesis. The kinetic pathways of crystallization reveal how the transformation of two different thermodynamically unstable phases, such as giniite (Fe5(PO4)4(OH)2∙2H2O) and Lithium sulfate (Li2SO4), leads to the same tavorite structure but with different morphologies based on the different mechanisms for crystal growth. Additionally, we provide standardized powder X-ray diffraction data and insights into the influence of the iron precursor on the crystal morphology of tavorite., S.F. thanks SEMAT at the University of Minho for the support. Work supported by the Portuguese Foundation for Science and Technology (FCT) under strategic funding UID/FIS/04650/2020 and UID/QUI/0686/2020, project PTDC/FIS-MAC/28157/2017, and contracts under the Stimulus of Scientific Employment, CEECIND/00833/2017 (R.G.) and 2020.04028 CEECIND (C.M.C.) as well POCH and European Union. Financial support from the Basque Government Industry Departments under the ELKARTEK, program is also acknowledged. Technical and human support provided by SGIker (UPV/EHU, MICINN, GV/EJ, EGEF and ESF) is gratefully acknowledged.

The demand for more efficient energy storage devices has led to the exponential growth of lithium-ion batteries. To overcome the limitations of these systems in terms of safety and to reduce environmental impact, solid-state technology emerges as a suitable approach. This work reports on a three-component solid polymer electrolyte system based on poly(vinylidene fluoride

Sodium hafnium germanate, Na3Hf1.7Ge3O10(OH)1.8, with garnet-type of structure was synthesized as a single phase, nanoparticles (100–600 nm) at mild hydrothermal conditions (230 °C) and autogenous pressure. The structure was solved ab initio from powder X-ray diffraction data and subsequently refined [Rexp: 6.10, Rwp: 7.26, Rp: 5.39, GOF: 1.19, RB: 1.50] by the method of Rietveld. The solid crystallizes in cubic space group Ia-3d (230), with a = 12.6819(2) A, V = 2039.65(1) A3 and Z = 8. The structure is built up of rare combination of two tetravalent (Ge4+ and Hf4+) and one monovalent (Na+) cation alternating in form corner-sharing GeO4 tetrahedra and HfO6 octahedra whose negative charge is compensated by Na+ residing in dodecahedral coordination. Unlike the typical tetrahedral site disorder in hydrogarnets (hydrogrossular, hibschite, and katoite) we found that the octahedral position of the heavy Hf4+ cation is partly vacant which reveals alternative mechanism of charge unbalance leading to incorporation of hydroxyl group. Furthermore, the synthesized material is the first hafnium germanate with garnet-type of structure and the second known sodium hafnium germanate.

Zeolites Y from organic-free system with adjustable Si/Al ratios (2.15–2.87) were synthesized and compared to the commercial zeolite Y (HSZ-320NAA, Tosoh Co., Japan). We found that the as-synthesized and commercial zeolites with similar X-ray crystallinity and Si/Al ratios tend to show different susceptibility to removal of framework aluminium. Furthermore, our study indicates that increased extraction of framework aluminium atoms not always result in lower crystallinity. We attribute this behaviour to different distribution of Si(nAl) building units and structural defects as revealed by 29Si MAS-NMR, 27Al MAS-NMR and powder XRD analyses. We also found that the progressively increasing amount of extra-framework aluminium is inversely related with the Si/Al ratios of the dealuminated samples and contributes to higher catalytic activity. Finally, we evaluated the influence of X-ray crystallinity and Si/Al ratios on the catalytic performance of the as-synthesized and commercial samples.

When external stimuli are applied on a ferroic material, an ordered microstructure with crystallographic deformations (twins) is formed within the initially homogeneous crystal. However, when the crystal twins are formed during the crystallization, their integrated effect on the crystal properties is poorly examined. This work reveals a mild hydrothermal synthesis of euhedral ferroelastic crystals of sodium germanium titanate (Na2TiGeO5) with ordered twin patterns that can be selectively manipulated with an adaptive beam of light. Within the idiomorphic crystals, a regular circuit of translucency adjustable sectors detached by the combination of permanent and switchable interfaces embedded in equivalent facets is found. The crystals also reveal a rare combination of chemically equivalent segments with contrasting refractive indexes. Finally, by simple fracturing of the crystals, a microstructural reorientation under ambient conditions is achieved.

The proposed work aims to functionalize leathers for footwear industry with antimicrobial properties based on AgTiO2 nanoparticles. The synthesis of nanoparticles was carried out by the hydrothermal method with significant advantages in terms of time, energy savings and low cost. Anatase TiO2 nanoparticles with dimensions below 10nm were obtained as observed by X-ray diffraction and transmission electron microscopy. Fourier transform infrared spectroscopy showed that the based structure of leather was not modified by the addition of the nanoparticles. The antimicrobial activity was evaluated and it was observed that Ag containing leathers gained antimicrobial activity. In addition, the nanoparticles were found to be non-cytotoxic. This achievement, by itself, should be quite appealing to the footwear industry as it could consist in a solid value-preposition given the commonness of fungal infections promoted by humidity, poor breathability and temperature that promote the expansion of the microflora of the skin., This research is sponsored by FEDER funds through theprogram COMPETE – Programa Operacional Factores de Competitividade and by the Portuguese Foundation for Science andTechnology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2013, and UID/EMS/00285/2013 and in the framework of ERA-SIINN/0004/2013 project., info:eu-repo/semantics/publishedVersion

Metronidazole (MNZ) is a recalcitrant antibiotic with toxic and carcinogenic effects in aquatic environments. In this work, Fe-5(FO4)(4)(OH)(3)center dot 2H(2)O (giniite) particles were synthesised with three different alkaline cations (Li+, Na+ and K+) and used as Fenton catalysts for MNZ removal. It is shown that the addition of different cations during the hydrothermal synthesis process promote different morphologies from asterisk-like to flower-like and branches-like, maintaining the crystalline structure of pure giniite. The photo-Fenton activity of these particles was then evaluated through the degradation of MNZ under sunlight radiation for 9 h. The results indicate that the alkaline cation has a predominant role in the photo-Fenton efficiency, as demonstrated by the superior degradation efficiencies of Na@giniite particles (91.2% and 72.5% with giniite concentration of 0.2 g L-1 and 0.07 g L-1, respectively), related with its high surface area (10.7 m(2) g(-1)). Thus, it is demonstrated the suitability of Na@giniite particles as Fenton catalyst for MNZ removal from water. (C) 2020 Elsevier Ltd. All rights reserved., This work was supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2020 and PEST-C/QUI/UIO686/2014 and under projects PTDC/BTM-MAT/28237/2017 and PTDC/FIS-MAC/28157/2017. We also thank the financial support from e FCT for grants SFRH/BD/122373/2016 (HS), SFRH/BPD/112547/2015 (CMC), IF/01516/2013 (SF), CTTI-70/19-CF(1) (P.M), and CEECIND/00833/2017 (RG). The authors thank funding by the Spanish State Research Agency (AEI) and the European Regional Development Fund (ERFD) through the project PID2019-106099RB-C43/AEI/10.13039/501100011033 and from the Basque Government Industry and Education Department under the ELKARTEK, HAZITEK and PIBA (PIBA-2018-06) programs, respectively.

LiMn2O4 and LiMn1.5M0.5O4 (M: Ni, Cu, Co) doped particles have been synthetized by sol-gel. Particles between 50 and 200 nm were obtained with the cubic spinel structure of the LiMn2O4. Ni doping shows a more efficient substitution in the octahedral 16d site, replacing the Mn3+ thorn ion, improving the important drawback of poor cycling behavior of LiMn2O4. The average pore size decrease with the addition of the doped elements in the LiMn2O4 structure from 2.9 to 2.6 nm. Thermal analysis shows that the doped particles present higher thermal stability that the undoped ones. Electrochemical behavior of the cathodes prepared with each of the active materials show that the doping influenced the electrochemical performance of the active material. Thus, a specific capacity of 33, 74, 44 and 53 mAh g(-1) (at C) and 74, 89, 59 and 69 mAh g(-1) (at C/10) were obtained for LiMn2O4, LiMn1.5Ni0.5O4, LiMn1.5Cu0.5O4 and LiMn1.5Co0.5O4 cathodes, respectively. All cathodes present good electrochemical stability with low capacity fade of 0.5 and 3.1% for LiMn1.5Ni0.5O4 and LiMn1.5Cu0.5O4, respectively, after 50 cycles. These results show an improvement of electrochemical performance for LiMn2O4 doped with Ni, Cu and Co, demonstrating their suitability for lithium-ion battery systems., Work supported by the Portuguese Foundation for Science and Technology (FCT) funds strategic funding UID/FIS/04650/2020 and UID/QUI/0686/2020, project PTDC/FIS-MAC/28157/2017, and Grants CEECIND/00833/2017 (R.G.) and SFRH/BPD/112547/2015 (C.M.C.). Financial support from the Basque Government Industry Department under the ELKARTEK and HAZITEK programs is also acknowledged. Technical and human support provided by SGIker (UPV/EHU, MICINN, GV/EJ, EGEF and ESF) is gratefully acknowledged.

Currently, the direct synthesis of faujasite-type (FAU) zeolites with Si/Al ratios greater than 3 depends on organic or inorganic additives. Here, we report the first additive-free synthesis of faujasite with Si/Al ratios greater than 3 using ultraviolet (UV) light assistance. The obtained zeolite shows excellent catalytic performance comparable to the commercial zeolite Y. published

Different aluminum and calcium based particles, montmorillonite (MMT), zeolites (NaY), bayerite (BAY) and hydroxyapatite (CaHAp), were compared and evaluated for water defluorination. The effect of parameters such as temperature of the medium, concentration (mass of adsorbent), reaction time and pH on the defluorination capacity were studied for the particles with best performance. MMT and CaHAp adsorbents showed increased fluoride rejections in batch experiments (approximate to 45 and 100%). The defluorination capacity of MMT is influenced by the concentration and pH, while for CaHAp is independent of the evaluated parameters within the measured range. Further, polymer composite membranes based on poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) and the adsorbents with higher defluorination capacity were prepared by thermally induced phase separation in order to produce active filters for fluoride removal from water. The composite membranes presented a homogeneous porous structure with degrees of porosity ranging between approximate to 20 and 76% and average pore size in the micron range. The permeability of the composite membranes ranged between 12,500 and 10,000 L/h.m(2).bar. A maximum fluoride rejection of 68% was obtained after 6 filtrations for the CaHAp/P(VDF-HFP) composite membranes. Thus, the composite membranes of P(VDF-HFP) with MMT and CaHAp show suitable performance for defluorination in water purification systems., This work was supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2013. The funds provided by FCT through the Chemistry Research Centre of the University of Minho (UID/QUI/00686/2013 and UID/QUI/0686/2016) are also gratefully acknowledged. JNP wish to thank the financial support of the project Centro-01-0145-FEDER-000017 - EMaDeS - Energy, Materials and Sustainable Development, co-financed by the Portugal 2020 Program (PT 2020), within the Regional Operational Program of the Center (CENTRO 2020) and the European Union through the European Regional Development Fund (ERDF). The authors acknowledge funding by the Spanish Ministry of Economy and Competitiveness (MINECO) through the project MAT2016-76039-C4-3-R (AEI/FEDER, UE) (including the FEDER financial support), and financial support from the Basque Government Industry Department under the ELKARTEK and HAZITEK program. PRS gratefully acknowledge DST Women Scientists Scheme-A (WOS-A) for the research grant SR/WOS-A/CS-91/2013., info:eu-repo/semantics/publishedVersion

Germanates with pyroxen-type of structure are generally considered a product of high-temperature synthesis conditions. This work shows for the first time mild hydrothermal synthesis of indium germanate (NaInGe2O6) with pyroxene-type of structure at 230 °C and autogenous pressure. The sample crystallizes as uniform bundle-like intergrowths of micron sized prismatic crystals with nanosized diameter. The refined crystal structure by the method of Rietveld provide novel crystallographic and standardized powder X-ray diffraction (XRD) data.

Phase pure sample of the microporous copper silicate CuSH–1Na has been obtained by simplified hydrothermal method without using additives (H2O2 and Na2HPO4). Ion exchange of Na+ by Cs+, Ca2+ and Sr2+ ions showed that the structure can suffer partial replacement of the charge compensating cations. Ion exchange with Cs+ resulted in distinct dehydration while the ion exchange with Sr2+ increased the total amount of water. Water content in the Ca-exchanged sample is comparable to the as-synthesized sodium phase. Raman spectroscopy revealed that the divalent cations as Ca2+ and Sr2+ induce stronger local structural deformations than the monovalent Cs+. These structural changes have been also followed by the refined lattice distortions. Magnetic analyses showed that CuSH–1Na presents a very weak ferromagnetic interaction along the Cu2+ chains with a nearly vanishing Curie–Weiss temperature. This magnetic coupling is associated with super-super-exchange interactions through Cu–Na–O–Na–Cu paths. Antiferromagnetic coupling, attributed to inter-chains super-super-exchange interactions, competes with the ferromagnetic one and prevails at the lowest temperature.

Two dicationic water soluble mixed triamine/diamine copper (II) complexes, of general formula [Cu(dien)NN]Br2(1–2) [dien = diethelenetriamine and NN is en = ethylenediamine or Me4en = N,N′,N,N′-tetramethylethylenediamine] were prepared under ultrasonic mode with a relatively high yield. These complexes were characterized by elemental microanalysis, UV visible IR spectroscopy, and thermal and electrochemical techniques. In addition, complex 2 structure was solved by X-ray single crystal and Hirshfeld surface analysis. The complex exhibits a distorted square pyramidal coordination environment around Cu(II) centre. The solvatochromism of the desired complexes was investigated in water and other suitable organic solvents. The results show that the Guttmann’s DN parameter values of the solvents have mainly contributed to the shift of the d–d absorption band towards the linear increase in the wavelength of the absorption maxima of the complexes. The complex 1 showed higher antibacterial activity against the studied microorganisms compared to complex 2. Both complexes revealed promising antibacterial activities., The authors would like to extend their sincere appreciation to the Deanship of Scientific Research at King Saud University for its funding of this Research group NO (RG-0257-1435-1436).

Lithium iron phosphate (LiFePO 4 ) with olivine structure was prepared by mild hydrothermal method at variable time, temperature, source of lithium and sucrose content. The relations between synthesis parameters and the characteristics (phase purity, lattice volume and morphological relations) of the obtained iron olivine samples were studied by powder X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results demonstrated that after a proper adjustment of the initial pH, lithium nitrate (LiNO 3 ) becomes an effective alternative to lithium hydroxide (LiOH) as source for lithium. Conditions that provide LiFePO 4 with adjustable lattice volume and new morphological features have been established. To our knowledge, this is the first mild hydrothermal synthesis of LiFePO 4 using LiNO 3 . Further, it is demonstrated that it can be applied for the development of Li-ion battery electrodes.

The existing concept for preparation of faujasite (FAU) type zeolite nanosheet assemblies is based on use of organic or extra inorganic morphology-directing templates or agents. Herein, a repetitive branching of hierarchically arranged nanolayers of FAU zeolite without employment of any morphology modifiers is demonstrated. This type of crystal growth is achieved only by kinetic control of carefully chosen conditions that border the co-crystallization of FAU- and EMT-type of zeolites. Furthermore, we provide evidence that the branching originates from recrystallization of zeolite nanoparticles followed by formation of submicron faceted crystals that further serve as nutrient for nanosheet structures. These findings open up a simple route to intergrowth of two-dimensional nanostructures of zeolites and may contribute to their scaled up production.

Polymer composite membranes based on poly(vinylidene fluoride-hexafluoropropylene), PVDF-HFP, with different aluminum hydroxide filler content, bayerite polymorph, were prepared by solvent casting for arsenic removal from water by filtration and adsorption. Morphological, structural and mechanical characterization of the membranes were performed. The arsenic removal efficiency of the membranes was also evaluated. Composite membranes presented homogeneous porous structures with a degree of porosity between 65 and 75%. They were hydrophobic e (contact angle >90°), showed a compressive strength >100 kPa and water flux ranging from 65 to 215 L/h m 2 . Further, arsenic rejections around 60% were found after 1 h reaction in dead-end cell filtration tests of an arsenic standard solution of 100 μg/L. A bayerite arsenic adsorption mechanism was also proposed. Thus, the PVDF-HFP/bayerite composite membranes showed a suitable performance for arsenic removal in water purification systems.

Different rare-earth elements (Dy, Gd, Tb and Yb) doped LiMn 2 O 4 spinel active material were prepared by sol-gel method. The rare earth doping elements decrease particle size but do not affect the formation of cubic spinel structure. Further, these dopants have strong influence in the overall electrical properties of the cathodes prepared from them. In the cyclic voltammetry measurements, two pairs of separated redox peaks are observed, independently to dopants. LiMn 2 O 4 doped gadolinium (Gd) and dysprosium (Dy) exhibit a comparable room temperature rate capability to pristine LiMn 2 O 4 with discharge capacity of 94.5 mAh g -1 and 82.3 mAh g -1 , respectively, versus 73.4 mAh g -1 for pristine LiMn 2 O 4 at a rate of C5. Terbium (Tb) and ytterbium (Yb) doping show, on the other hand, lower performance. After 50 cycles at C2, the capacity fade is 7% for LiMn 1.95 Dy 0.05 O 4 and 14% for LiMn 1.95 Gd 0.05 O 4 , whereas for LiMn 2 O 4 it is 32%. The improved cycling performance of LiMn 2 O 4 doped with Gd and Dy is attributed to the powder size and atomic radius of the elements. Differences of the capacity retention on cycling are attributed to superior structural stability due to rare earth doping. These results indicate that improved cathode materials doped with rare earth element are suitable for lithium-ion battery applications, This work is funded by FCT – Fundação para a Ciência e a Tecnologia, in the framework of the PTDC/CTM-ENE/5387/2014 and PTDC/EEI-SII/5582/2014 projects. A. G. and C.M.C. also thanks the FCT for the grant SFRH/BD/90313/2012 and SFRH/BPD/112547/2015, respectively. The authors thank funding from the FCT under the Indo-Portuguese program of cooperation in science and technology (INT/Portugal/P-02/2013) 2014-2016. The fellowship from MHRD, Govt. of India was acknowledged for Pura Ram. The authors thank financial support from the Basque Government Industry Department under the ELKARTEK Program. SLM thanks the Diputación de Bizkaia for financial support under the Bizkaia Talent program; European Union’s Seventh Framework Programme; Marie Curie Actions – People; Grant agreement nº 267230.

This work is funded by FEDER funds through the “Programa Operacional Factores de Competitividade – COMPETE” and by national funds from FCT – Fundacao para a Ciencia e a Tecnologia, in the framework of the strategic project Strategic Project PEST-C/FIS/UI607/2014. A. G. and C.M.C. also thanks the FCT for the grant SFRH/BD/90313/2012 and SFRH/BPD/112547/2015, respectively. The authors thanks to the Phostech and Solvay companies for the high quality of the materials provided.

The current know-how in the classical additive-free synthesis of layer-like faujasites is limited to a time for crystallization that is times longer than the few hours (5–8 h) necessary for the preparation of their octahedron-like counterparts. Furthermore, it is widely believed that the temperature for crystallization of layered-like assembles of FAU-type of zeolites should be lower (20–50%) than the one in conventional two-step synthesis of classical faujasites. In contrast, I present direct additive-free synthesis of nanolayer (0.15 ± 0.03 μm) intergrowths (1.3 ± 0.1 μm) of FAU-type of zeolites at the conventional 90 °C for the exceptionally short time of 4 h. Additionally, this work shows that in gel the layer-like structures are formed by oriented aggregation of nanoparticles that later crystallize to faujasite.

LiMn1.5Ni0.5O4 with spinel type of structure was synthesized by sol-gel method and doped by different rare-earth elements (Nd, Gd and Dy). It was found that the inclusion of rare-earth element preserves the cubic spinel structure, leads to smaller particle size and improves the cyclic performance of the produced batteries. The best battery performance was obtained after doping the spinel structure by Gd. Among the used rare-earth elements Gd is the only one with stable oxidation state of 3 + which leads to stabilization of the Mn dissolution.Thus, the improvements observed in battery performance (rate performance and cycle life) are due to the superior structural stability of the doped active materials. It is concluded that the LiMn1.48Ni0.5Gd0.02O4 sample is the one with the best overall performance to act as active material for cathodes in rechargeable lithium-ion batteries., This work was supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2013. The authors thank FEDER funds through the COMPETE 2020 Programme and National Funds through FCT under the projects PTDC/CTM-ENE/5387/2014 and UID/CTM/50025/2013 and grants SFRH/BD/90313/2012 (A.G.), SFRH/BD/88397/2012 (R.G.) and SFRH/BPD/112547/2015 (C.M.C.). The authors are thankful for funding from the FCT under the Indo-Portuguese program of cooperation in science and technology (INT/Portugal/P-02/2013) 2014-2016. The fellowship from MHRD, Govt. of India was acknowledged for Pura Ram. Financial support from the Basque Government Industry Department under the ELKARTEK Program is also acknowledged. The authors acknowledge the MRC, MNIT, Jaipur, Rajasthan, India for TEM, RAMAN characterization facilities for material characterization., info:eu-repo/semantics/publishedVersion

In geoscience the pyroxens are important indicator for the physicochemical conditions in the upper mantle of Earth and their laboratory preparation is often featured by extreme conditions of crystallization. In this work, for the first time mild hydrothermal conditions (230 °C and autogenous pressure) for the synthesis of NaVSi 2 O 6 pyroxene are revealed. This is also the first pyroxene prepared in nanometric size. The chemical composition, crystal morphology and size are revealed by energy dispersive spectrometry (EDS) and scanning electron microscopy (SEM). The phase purity and details from the crystal structure are confirmed by the method of Rietveld. As a result standardized powder X-ray diffraction (XRD) data are provided.

The synthetic analogue of the mineral giniite is a promising material for capture of phosphopeptides from complex tryptic digests, photocatalysis and cathode for lithium battery applications. In all these applications, the crystal morphology of giniite shows to be extremely important, however, the reported synthesis and crystal morphologies are scattered among a variety of approaches. Here we report a hydrothermal synthesis that allows achieving five different morphologies of giniite only by changing the pH by addition of three different alkaline cations (Na+, Li+ and K+) in form of hydroxides. At pH 2, micrometric sphere-like assemblies of nanoparticles were obtained. At pH 4, fractal dendritic crystals as well as intergrown flower-like and asterisk-like crystals were synthesized. At pH 6, the synthesis resulted in dagger-like crystals of dissolved dendritic structures., This work was supported by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2013. We thank FEDER funds through the COMPETE 2020 Programme and National Funds through FCT under the projects PTDC/CTM-ENE/5387/2014 and UID/CTM/50025/2013 and grants SFRH/BD/88397/2012 (R.G.), SFRH/BPD/112547/2015 (C.M.C.), and IF/01516/2013 (S.F.). S.L.M. thanks financial support from the Basque Government Industry Department under the ELKARTEK Program., info:eu-repo/semantics/publishedVersion

This work is devoted to study the photocatalytic ability of cotton textiles functionalized with SiO2-TiO2 and SiO2-TiO2-HY composites to degrade a dye molecule. Coatings were prepared by sol-gel method and calcined at different temperatures in a range of 400–750 °C. FTIR confirmed the existence of SiOTi bounds and the band located in the region between 570 and 600 cm−1 was used to calculate the framework Si/Al ratio of HY in the SiO2-TiO2-HY composites. XRD confirmed the presence of nanosized TiO2 (anatase phase) in all calcined composites. Nitrogen adsorption isotherms showed a decrease in surface area and pore volume for higher calcination temperature. A simple mechanical process was used to impregnate the different composites on the cotton substrates. The photocatalytic activity of cotton textiles functionalized with SiO2-TiO2 and SiO2-TiO2-HY composites was tested via the degradation of Rhodamine B (RhB) dye under similar solar irradiation. The best catalytic performance was achieved with the SiO2-TiO2 and SiO2-TiO2-HY composites subjected to a calcination treatment at 400 °C, whereas SiO2-TiO2 presented a decolourization and mineralization around 94% and 89%, respectively, after 2 h of irradiation. Furthermore, the products of RhB degradation were analysed and identified by using HPLC-ESI–MS and ion chromatography techniques and a photocatalytic mechanism was proposed., The authors thank CAPES from Brazil for the financial support of this work. This work is also a result of project “AIProcMat@N2020 − Advanced Industrial Processes and Materials for a Sustainable Northern Region of Portugal 2020”, with the reference NORTE-01-0145-FEDER-000006 and the project BioTecNorte (operation NORTE-01-0145-FEDER-000004), supported by Norte Portugal Regional Operational Programme (NORTE 2020), under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (ERDF). This work also has been funded by ERDF through COMPETE2020 − Programa Operacional Competitividade e Internacionalização (POCI), Project POCI-01-0145-FEDER-006984 − Associate Laboratory LSRE-LCM and by national funds through FCT − Fundacão para a Ciência e a Tecnologia for project PTDC/AAGTEC/5269/2014 and Centre of Chemistry (UID/QUI/00686/2013 and UID/QUI/0686/2016)., info:eu-repo/semantics/publishedVersion

LiMn2-xGdxO4 (x=0.00, 0.01 and x=0.04) spinel active material were prepared by sol-gel method. The morphology, crystal structure, thermal stability and electrochemical properties of the synthesized samples were evaluated. Gd-doping maintains the cubic spinel structure of LiMn2O4, leads to a decrease of the average particle size, and has a strong influence on the electrochemical properties of the cathodes. LiMn2-xGdxO4 cathode materials show two pairs of separated redox peaks, independently of the Gd-doping. After 40 charge-discharge cycles at C2, the discharge capacity was 55.9 mAh.g-1 and 33 mAh.g-1 for x=0.04 and x=0, respectively, corresponding to a capacity retention of 80% and 70%, respectively. The Gd-doped with x=0.04 showed improved cycling performance with respect to pristine LiMn2O4 due the smaller particle size and superior structural stability, showing its suitability for lithium-ion battery applications., The authors thank FEDER funds through the COMPETE 2020 Programme and National Funds through FCT - Portuguese Foundation for Science and Technology under Strategic Funding UID/FIS/04650/2013. A. G., C.M.C. and S. F. thank the FCT for grants SFRH/BD/90313/2012, SFRH/BPD/112547/2015 and IF/01516/2013, respectively. The authors thank funding from the FCT under the Indo-Portuguese program of cooperation in science and technology grant INT/Portugal/P-02/2013, 2014-2016. The authors are thankful for HRTEM and Raman characterization support from MRC, MNIT, Jairpur, INDIA. The fellowship from MHRD, Govt. of India was acknowledged for Pura Ram. SLM thanks financial support from the Basque Government Industry Department under the ELKARTEK Program.

The time-dependent study at mild hydrothermal conditions revealed the kinetic relation between structurally unrelated bismuth ferrites. We report the synthetic conditions that disclose the in situ transformation of Bi25FeO39 into BiFeO3 by only extending the time for crystallization. We also demonstrate how a careful investigation of the early stages of multiferroics crystallization provides cheap and easy room-temperature access to the important sillenite-type of structure of Bi25FeO39. The crystal structure analysis by the Rietveld method and magnetization measurements provided detailed structure and magnetic relations between the synthesis conditions and the properties of the run product. The BiFeO3 antiferromagnetic behavior with a small ferromagnetic component arising from the particle's surface uncompensated spins is ascertained.

At mild hydrothermal conditions triclinic modifications of BaMP 2 O 7 (M = Mn and/or Cu) have been succeeded. The method offers cheap, one step, impurity free and chemical flexible fabrication of family of metal phosphates that are potential low-dimensional quantum magnets. Partial isomorphous substitution of the Mn 2+ by Cu 2+ resulted into mixed-metal solid that has been structurally and magnetically characterized. Rietveld refinement study confirmed the structures and revealed the influence of transition metal substitution. The temperature-dependent magnetic measurements revealed that the system is paramagnetic in almost all temperature range and an apparent antiferromagnetic phase transition occurs around 5 K. Using the Curie–Weiss law, a Curie–Weiss temperature, θ P = −11.0 K, and a Curie constant C = 3.39 emu K mol −1 was obtained. The small negative θ P value and the χT behavior as a function of temperature reveal a weak antiferromagnetic interaction between the Cu 2+ /Mn 2+ magnetic centers.

Solids with spinel-type of structure attract considerable interest since they are important indicator for the processes in the Earth mantle and more recently appeared as promising candidates for semiconductors, photocatalysts and quantum magnets. In this work, for the first time low temperature (230 °C) and autogenous pressure are established for preparation of spinel-type of copper germanate whose synthesis was known only at the combination of high pressure and high temperature. The revealed hydrothermal conditions offer one-step preparation of high crystalline, phase pure nanoparticles of Cu2GeO4 whose structure was confirmed by the method of Rietveld providing standardized structural data extracted from powder sample. Finally, the established easy access to Cu2GeO4 offers an excellent opportunity for experimental studies of exotic ground states and non-trivial low-temperature properties as predicted by previous theoretical calculations.

Copper zirconium phosphate hydrate (Cu(OH)(2)Zr(HPO4)2 center dot 2H(2)O, hereafter referred to as Cu-alpha-ZrP) with high crystallinity was directly synthesized in a NaF-CuO-ZrO-P2O5-H2O system under hydrothermal conditions. The copper ion was confirmed to be an exchangeable cation in the Cu-alpha-ZrP through elemental analysis and a proton ion exchange process. The crystal structure of the Cu-alpha-ZrP was determined ab initio by using X-ray powder diffraction data. In the structure, the CuO6 octahedron would be located in an exchangeable atom position. Moreover, Cu-alpha-ZrP was evaluated as an additive in grease in a four ball test. The maximum nonseizure load (P-B, representing the load-carrying capacity) of the base grease containing Cu-alpha-ZrP was increased from 353 to 1235 N. The excellent load-carrying capacity may be explained by the easier adherence of the material to the worn surface forming a tight protective film.

For the first time tin silicate with umbite structure K2SnSi3O9·H2O (AV-6) has been prepared from clear solution using SnCl2 as a source of tin. In situ high temperature powder X-ray diffraction study of AV-6 and its copper ion exchanged form K0.98Cu0.51SnSi3O9·2H2O (Cu-AV-6) has been performed. Rietveld refinement revealed that the ion exchange with copper alters the initial orthorhombic structure into monoclinic one. In this way the temperature stable framework of AV-6 has been transformed into thermally flexible material that can be contracted at 200 °C and preserved at ambient conditions. At higher temperatures (300–700 °C) the structure gradually amorphisize and at 750 °C it transforms into nanosized cassiterite type solid. We also study the structural reversibility and the influence of the dehydration process on the dimensions of the both structures.

Microporous titanosilicate K–Na–ETS-4 has been synthesized and exchanged to Mg2+, Ba2+, and Cs+ forms. The structures were determined from single crystal X-ray diffraction data and the compositions were confirmed by energy dispersive X-ray spectroscopy. The inclusion of the Ba2+ caused a substantial framework contraction and the obtained data suggested a change from five- to six-coordination of the titanium atom belonging to the titanosilicate bridging unit. Both Ba2+ and Cs+ ions substitute water molecules and charge compensations ions, while Mg2+ prefers to occupy the position of Na+. All structures were refined in space group Cmmm having stoichiometric formulas: K3.25Na2.12H3.63Si12Ti5O38(OH)·10.64H2O; K2.63Mg1.44H3.49Si12Ti5O38(OH)·7.92H2O; K1.18Na1.20Cs4.01H2.61Si12Ti5O38(OH)·7.12H2O and Ba4.31H0.39Si12Ti5O39·4.52H2O. The obtained results may help understanding the cation exchange, thermal and gas separation properties of ETS-4.

Molecular recognition at interfaces is essential approach for growth of crystals with selectively exposed facets. In general, this process is guided by impurities or solvents that favor the development of surfaces with particular reticular density. However, the specific agents that direct the crystal habit of one system often remain irrelevant for another, and thus, the control of crystal surface of many materials is still poorly known. Here we show selective resizing of prismatic crystal facets of germanium clinopyroxene (NaFeGe2O6) only by a simple switch between nitrate (Fe3+), chloride (Fe3+), and sulfate (Fe2+) sources of iron. The observed effect is explained by the combination of different rates of ion transport to the crystal surface and binding affinity of the hydrolyzed derivatives of the iron precursors that cap the crystal surface during the crystallization. Furthermore, this work reveals the first mild hydrothermal synthesis of germanium clinopyroxene, This work was supported by the Fundaçã̧o para a Ciência e a Tecnologia (FCT) − “Investigador 2013 (IF/01516/2013)”.

The framework flexibility of the nanosized rhombohedrally distorted titanosilicate analog of the mineral pharmacosiderite (RTS) has been in situ studied by powder X-ray diffraction at elevated temperatures. Between 30 and 175 °C the rhombohedral lattice showed tendency to shrink and open the angle of the axes. At 125 °C the cell distortion resulted in pseudo cubic cell metrics where the reflections (0 2 1), (0 1 −2), (2 1 1), (2 2 0), (3 0 1) and (3 1 1) have been reduced. After heating at 175 °C the recovery of the reduced reflections has not been completed and the lattice remained shrank at room temperature.

The mild hydrothermal synthesis, crystal structure, photoluminescence properties and emission quantum yield of a new sodium zirconium germanate are reported. This material and the method for its preparation represent for the first time a germanium garnet-type material synthesized at autogenous pressure and temperature at 230 °C. The crystal structure was determined by starting from the crystallographic parameters of a common garnet structure and it represents not only a new chemical combination of atoms but also combination of oxidation states in garnet structure. The framework consists of interconnected corner sharing GeO4 tetrahedra and ZrO6 octahedra which form small cavities that accommodate charge compensation Na+ cations. In the course of synthesis the structure can be functionalized by in situ doping with different percentage of Eu3+ ions. This structural flexibility is used to explore the photoluminescent behavior of the active centers embedded in garnet-type host. The materials display the Eu3+ 5D0→7F0–4 transitions under excitation via intra-4f6 excitation levels and through the O2−→Eu3+ ligand-to-metal charge transfer. A maximum 5D0 quantum efficiency and emission quantum yield values (ca. 0.28 and 0.04±0.01, respectively) were found for the low Eu3+-containing sample, suggesting the presence of concentration quenching effects at higher Eu3+-content (5%).

In organic-free system, microstructures of natisite [Na2(TiO)SiO4] via mechanisms of selective and oriented dissolution and recrystallization have been revealed. The growth of faceted natisite crys...