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Hydrogen peroxide assisted sol–gel coating of core-shell microcapsules of phase change materials (PCMs) is reported. A doubly coated paraffin core with an inner poly(melamine-formaldehyde) shell and an outer coating of peroxostannate, peroxoantimonate, their mixture or the respective metal oxides are reported. Triple coating of the paraffin core with a poly(melamine-formaldehyde) inner shell, tin oxide middle layer and graphene oxide outer coating is also achieved by hydrogen peroxide sol–gel processing. The latent heats of the microencapsulated PCMs ranged between 122 and 192 J g−1. The sol–gel process involves stabilization of the peroxostannate or peroxoantimonate sol in basic aqueous hydrogen peroxide and subsequent destabilization and deposition of the sol by addition of an antisolvent. Transformation to the metal oxide coating is conducted by chemical reduction with sodium sulfite or by mild heat treatment without leakage of the paraffin core.

We introduce a green synthesis approach for high-performance sodium-ion battery anodes that does not involve hydrothermal treatment or excessive energy use. Wet chemistry involving ammonium peroxostannate intermediate coating of reduced graphene oxide can be done at low temperature without excessive use of solvents. The process is practically waste-free and does not involve acid waste. Thermal treatment is required only for the solid material. The electrode exhibited very high stability and the charging capacity was reduced from 320 to 310 mA h g–1 after 2000 cycles at 3 A g–1. Moreover, the synthesis protocol demonstrated here is highly versatile with different, alternative pathways that provide many degrees of freedom in the process sheet design and in material composition.

Potassium-ion batteries are attracting considerable attention as a viable type of high voltage battery. Among available anode materials, composites containing Sb2S3are some of the most interesting high capacity candidates. A nanostructured Sb2S3-reduced graphene oxide composite anode material is evaluated in this study and compared with a structurally similar SnS2-reduced graphene oxide material reported previously by this team. The behaviour of the Sb2S3-based electrodes is assessed in both 1 M KPF6in ethylene carbonate-diethyl carbonate and 1 M KPF6in 1,2-dimethoxyethane electrolytes. Depotassiation capacities in excess of 650 mA h g−1are recorded for the composite electrodes, superior not only to SnS2-based electrodes but also to all previously reported Sb2S3-containing electrode materials for potassium-ion batteries. In order to establish insights into the reaction mechanism of the Sb2S3phase with potassium, post-cycling X-ray diffraction andin situtransmission electron microscopy are utilised. The recorded data suggest the presence of antimony alloys and potassium polysulphides as reaction products and intermediates; a possible conversion-alloying reaction mechanism is discussed. The results indicate that a capacity higher than previously believed is achievable in the Sb2S3active component of potassium-ion battery electrodes.

Nanocrystalline zinc peroxide is passivated against further oxidation by the addition of minute, substoichiometric amounts of potassium permanganate, which also endows it with increased thermal sta...

High, nearly 100%, yield synthesis of ammonium peroxogermanate (APG), (NH4)6[Ge6(μ-OO)6(μ-O)6(OH)6]·6H2O, is presented, and its crystal structure is determined by single crystal X-ray study. It comprises centrosymmetric hexanuclear peroxogermanate anions [Ge6(μ-OO)6(μ-O)6(OH)6]6- with six μ-oxo- and six μ-peroxo groups forming negatively charged layers. The space between these layers is filled by ammonium cations and water molecules, forming a highly stable structure due to hydrogen bonding. Highly soluble macroporous amorphous germanium oxide (HSGO) is then synthesized by mild treatment of APG. The compound forms highly oversaturated metastable germanium oxide solution with a solubility of 100 g/L, over 20 times higher than the solubility of amorphous germanium oxide. HSGO solution is a versatile reagent that can react with basic and acidic reagents to give a diverse range of salts including, e.g., germanium sulfide, germanium hydrophosphate, and potassium germanate. In the absence of acid or base, the aqueous HSGO solution yields hexagonal germanium oxide under ambient conditions.

Herein, peroxosolvates of the cyclic dipeptides disarcosine (C6H10N2O2·H2O2), dialanine (C6H10N2O2·2(H2O2)), diglycine (C4H6N2O2·2(H2O2) and C4H6N2O2·1.786(H2O2)·0.214(H2O)) were synthesized and studied by single crystal X-ray analysis and periodic DFT calculations. The hydrogen bonding networks of cyclic diglycine peroxosolvate and isomorphous hydrate were characterized using Bader analysis of periodic electron density and empirical correlations between enthalpy and metric and spectroscopic parameters of the H-bond. The obtained data for the peroxosolvate of cyclic dipeptides provided a molecular-level insight into the non-redox interaction of hydrogen peroxide with the peptide backbone in aqueous systems. In all structures, H2O2 acts as a proton donor in two hydrogen bonds. The carbonyl oxygen atom of the peptide (–CO–NH–) forms a relatively stronger hydrogen bond with the hydrogen peroxide molecule (32–34 kJ mol−1) as compared to that with water in the isomorphous hydrate of cyclic diglycine (26–28 kJ mol−1). The hydrogen atom of the peptide group (–CO–NH–) can form a moderate H-bond with hydrogen peroxide (25 kJ mol−1). The total hydrogen bonding energy of the peroxosolvate is higher than that of the corresponding hydrate (91 vs. 82 kJ mol−1). The stronger hydrogen bonding in peroxosolvates as compared to that in the hydrate and the fact that the intermolecular H-bonds C(O)NH⋯OCNH between cyclic dipeptides are not found in peroxosolvates, despite being prevalent in the structure of nonsolvated dipeptides, imply that hydrogen peroxide can interfere with the secondary structure of proteins via a mechanism that can lead to reversible inhibition or signaling in living systems.

A combined procedure of zinc peroxide granulation and encapsulation in one technological stage has been developed, which ensures the stabilization of ZnO2 by forming a coating on the surface of the product granules. It is shown that the use of sodium polyphosphate in a combined process of granulation and encapsulation as encapsulating agents with the concentration in the initial solution of 1% allows obtaining a capsular product, which is significantly more resistant to the action of wet carbon dioxide than a nonencapsulated analogue.

The review addresses synthetic approaches to composite materials based on graphene oxide and nano tin dioxide and their electrochemical properties as anodes for lithium- and sodiumion batteries. The introduction of a carbon matrix into the composite material improves the electrochemical characteristics of the anodes. In most methods, the synthesis of graphene oxide–tin dioxide composites is based on the use of tin(II,IV) chlorides as the starting compounds, and the most efficient electrode materials were obtained by the hydrothermal or solvothermal routes. Thermal processing is much more economic than the gas phase deposition protocols but requires heating of a large volume of dilute tin oxide dispersions in an autoclave. Mechanochemistry (ball milling) is also economically unfavorable for the synthesis of composite materials. In addition, large volumes of acidic wastes that should be neutralized and safely discarded are formed when tin chlorides are used. An alternative environmentally friendly technique based on the use of aqueous peroxide solutions can be applied for the production of efficient anode materials based on graphene oxide and tin dioxide. This process does not involve acidic wastes, uses hydrogen peroxide and ethanol as reagents, and accomplishes film deposition (coating) at room temperature. Final thermal treatment is required only for the active material, which minimizes energy expenses and equipment costs.

Formation of vanadium oxide nanofilm-coated graphene oxide (GO) is achieved by thermally induced explosive disintegration of a microcrystalline ammonium peroxovanadate-GO composite. GO sheets isolate the microcrystalline grains and capture and contain the microexplosion products, resulting in the deposition of the nanoscale products on the GO. Thermal treatment of the supported nanofilm yields a sequence of nanocrystalline phases of vanadium oxide (V3O7, VO2) as a function of temperature. This is the first demonstration of microexplosive disintegration of a crystalline peroxo compound to yield a nanocoating. The large number of recently reported peroxide-rich crystalline materials suggests that the process can be a useful general route for nanofilm formation. The V3O7@GO composite product was tested as a sodium ion battery anode and showed high charge capacity at high rate charge-discharge cycling (150 mAh g-1 at 3000 mA g-1 vs 300 mAh g-1 at 100 mA g-1) due to the nanomorphology of the vanadium oxide. NRF (Natl Research Foundation, S’pore)

High-charge-capacity sodium-ion battery anodes made of Sb2Te3@reduced graphene oxide are reported for the first time. Uniform nano-coating of graphene oxide is carried out from common sol of peroxotellurate and peroxoantimonate under room temperature processing. Reduction by hydrazine under glycerol reflux yields Sb2Te3@reduced graphene oxide. The electrodes exhibit exceptionally high volumetric charge capacity, above 2300mAhcm-3 at 100mAg-1 current density, showing very good rate capabilities and retaining 60% of this capacity even at 2000mAg-1. A comparison of sodiation and lithiation shows that lithiation exhibits better volumetric charge capacity, but surprisingly only marginally better relative rate capability retention at 2000mAg-1. Tellurium-based electrodes are attractive due to the high volumetric charge capacity of Te, its very high electric conductivity, and the low relative expansion upon lithiation/sodiation.

A composite based on sodium germanate and reduced graphene oxide was obtained for the first time by precipitating the initial peroxogermanate on a graphene oxide followed by heat treatment in vacuum. According to powder X-ray diffraction, sodium germanate crystallizes during the heat treatment in vacuum at 500°C. Scanning transmission electron microscopy examination showed that sodium peroxogermanate nanoparticles form a thin film on the surface of graphene oxide flakes. The electrochemical characteristics of composites obtained with different heat treatment conditions were studied as the anodes of lithium ion batteries.

High‐charge‐capacity sodium‐ and lithium‐ion battery anodes based on tin telluride are reported for the first time. Graphene oxide/cubic β‐SnTe electrodes exhibit exceptionally high reversible volumetric charge capacities above 3000 and 1300 mAh cm−3 at 100 mA g−1 charging rate for lithium and sodium ion batteries, respectively, and they show very good rate capabilities retaining 68 and 60 % of the respective capacities even at 2000 mA g−1 charging rate. The reversible charge capacity for lithiation is approximately equal to the theoretical value of the active material. The superior electrode performance is attributed to the high conductivity of tellurium, the mechanical buffering of volume changes by the large row‐V host elements, the elasticity of the reduced graphene oxide support, and the very low specific equivalent volumes involved in sodiation and lithiation of SnTe. NRF (Natl Research Foundation, S’pore)

We report the first attempt to study the behavior of the [AlO4Al12(OH)25(H2O)11]6+ (Al13) Keggin cation (KC) in water–peroxide solutions. Addition of hydrogen peroxide into an aqueous solution containing the Al13 KC reduces pH due to the acidity of hydrogen peroxide. According to the 27Al NMR studies of water–peroxide solutions prepared just before the NMR experiment, with their pH adjusted to the initial value of 5.5 with aqueous NaOH, the Al13 KC concentration decreases immediately once hydrogen peroxide is added to the initial system. Addition of 18.2 wt % hydrogen peroxide to the initial 0.88 mM Al13 solution gives rise to a fourfold decline in Al13 polyoxo cation concentration to 0.22 mM. Then, the KC concentration in the test system remains unchanged for 1 week. Large hydrogen peroxide amounts (27.9 wt % or higher) added to the initial system almost completely degrade the KC. Sodium sulfate added to the initial water–peroxide solution of Al13 chloride where the hydrogen peroxide concentration is 5.5 wt % precipitates the earlier described Al13 sulfate [AlO4Al12(OH)25(H2O)11](SO4)3 · 16H2O, where the aluminum polyoxo cation does not contain coordinated hydrogen peroxide molecules, peroxo or hydroperoxo groups as shown by X-ray diffraction.

The title adduct, C14H13NO·H2O2, consists of (Z)-N-benzylidene-1-phenylmethanamine oxide and hydrogen peroxide molecules in a 1:1 ratio. The organic coformer adopts a skew geometry with an inter-aryl-ring dihedral angle of 81.9 (2)°. In the crystal, the organic and peroxide molecules are linked through both peroxide O—H donor groups to oxide O-atom acceptors, giving one-dimensional chains extending along thebaxis. Present also are weak intermolecular C—H...O hydrogen-bonding interactions.

Peroxosolvates of 2-aminonicotinic acid (I) and lidocaine N-oxide (II) including the largest insular hydrogen peroxide clusters were isolated and their crystal structures were determined by single-crystal X-ray diffraction. An unprecedented dodecameric hydrogen peroxide insular cluster was found in I. An unusual cross-like pentameric cluster was observed in the structure of II. The topology of the (H2 O2 )12 assembly was never observed for small-molecule clusters. In I and II new double and triple cross-orientational disorders of H2 O2 were found. Cluster II is the first example of a peroxosolvate crystal structure containing H2 O2 molecules with a homoleptic hydrogen peroxide environment. In II, a hydrogen bond between an H2 O2 molecule and a peptide group -CONH⋅⋅⋅O2 H2 was observed for the first time.

A combined granulation and encapsulation procedure in the production of sodium percarbonate (SPC) has been developed that enables the stabilization of SPC to form a coating on the surface of product granules in one technological stage. The separation of the granulating and encapsulating agents during the drying process and formation of an encapsulating coating are performed due to large differences in the solubility of the components of initial solution. Sodium polyphosphate or oxyethylidenediphosphonic acid used as encapsulating agents with an initial solution concentration (1%) in the combined granulation and encapsulation process enables the preparation of encapsulated SPC, which is significantly more resistant to wet carbon dioxide than unencapsulated product.

A peroxogermanate thin film was deposited in high yield at room temperature on graphene oxide (GO) from peroxogermanate sols. The deposition of the peroxo-precursor onto GO and the transformations to amorphous GeO2, crystalline tetragonal GeO2, and then to cubic elemental germanium were followed by electron microscopy, XRD, and XPS. All of these transformations are influenced by the GO support. The initial deposition is explained in view of the sol composition and the presence of GO, and the different thermal transformations are explained by reactions with the graphene support acting as a reducing agent. As a test case, the evaluation of the different materials as lithium ion battery anodes was carried out revealing that the best performance is obtained by amorphous germanium oxide@GO with >1000 mAh g–1 at 250 mA g–1 (between 0 and 2.5 V vs Li/Li+ cathode), despite the fact that the material contained only 51 wt % germanium. This is the first demonstration of the peroxide route to produce peroxogermanate ...

Sodium peroxostannate nanoparticles with graded composition were produced from aqueous hydrogen peroxide–sodium hydroxostannate solution. The uniform particles were converted to composition graded sodium stannate by mild thermal treatment for peroxide decomposition and yielded yolk–shell tin dioxide particles by dilute acid treatment. The mechanism of formation of the graded sodium concentration is explained in view of the solubility of peroxostannate in H2O2–H2O solution and based on 119Sn NMR, XRD, dynamic light scattering (DLS) and electron microscopy studies. Initial studies illuminating sensitive hydrogen sensing by yolk–shell tin oxide particles are presented.

An anode material incorporating a sulfide is reported. SnS2 nanoparticles anchored onto reduced graphene oxide are produced via a chemical route and demonstrate an impressive capacity of 350 mA h g−1, exceeding the capacity of graphite. These results open the door for a new class of high capacity anode materials (based on sulfide chemistry) for potassium-ion batteries.

The Cambridge Structural Database has been used to investigate the detailed environment of H2O2 molecules and hydrogen-bond patterns within “true” peroxosolvates in which the H2O2 molecules do not interact directly with the metal atoms. A study of 65 crystal structures and over 260 hydrogen bonds reveals that H2O2 always forms two H-bonds as proton donors and up to four H-bonds as a proton acceptor, but the latter can be absent altogether. The necessary features of peroxosolvate coformers are clarified. (1) Coformers should not participate in redox reactions with H2O2 and should not catalyze its decomposition. (2) Coformers should be Bronsted bases or exhibit amphoteric properties. The efficiency of the proposed criteria for peroxosolvate formation is illustrated by the synthesis and characterization of several new crystals. Conditions preventing the H2O2/H2O isomorphous substitution are essential for peroxosolvate stability: (1) Every H2O2 in the peroxosolvate has to participate in five or six hydrogen b...

Using peroxostannate as a precursor, a composite material based on tin dioxide and carbon black was obtained, in which tin dioxide forms a coating on the surface of carbon black nanoparticles. The synthesized material was characterized by electron microscopy and X-ray powder diffraction analysis, and also the electrochemical characteristics of this material as an anode material for lithium-ion batteries were studied. The material demonstrates good stability and rate performance, which is indicative of the efficiency of the peroxide method for producing promising inexpensive anode materials based on tin dioxide and carbon black.

A tin dioxide–sodium stannate composite has been obtained by the thermal treatment of sodium peroxostannate nanoparticles at 500°C in air. X-ray powder diffraction study has revealed that the composite includes crystalline phases of cassiterite SnO2, sodium stannate Na2Sn2O5, and sodium hexahydroxostannate Na2Sn(OH)6. Scanning electron microscopy has shown that material morphology does not change considerably as compared with the initial tin peroxo compound. Electrochemical characteristics have been compared for the anodes of lithium-ion batteries based on tin dioxide–sodium stannate composite and anodes based on a material manufactured by the thermal treatment of graphene oxide–tin dioxide–sodium stannate composite at 500°C in air.

A novel composite material for the encapsulation of redox enzymes was prepared. Reduced graphene oxide film with adsorbed phenothiazone was used as a highly efficient composite for electron transfer between flavin adenine dinucleotide (FAD)-dependent glucose dehydrogenase and electrodes. Measured redox potential for glucose oxidation was lower than 0 V vs Ag/AgCl electrode. The fabricated biosensor showed high sensitivity of 42 mA M(-1) cm(-2), a linear range of glucose detection of 0.5-12 mM, and good reproducibility and stability as well as high selectivity for different interfering compounds. In a semibiofuel cell configuration, the hybrid film generated high power output of 345 μW cm(-2). These results demonstrate a promising potential for this composition in various bioelectronic applications.

Tellurium-peroxo complexes in aqueous solutions have never been reported. In this work, ammonium peroxotellurates (NH4 )4 Te2 (μ-OO)2 (μ-O)O4 (OH)2 (1) and (NH4 )5 Te2 (μ-OO)2 (μ-O)O5 (OH)⋅1.28 H2 O⋅0.72 H2 O2 (2) were isolated from 5 % hydrogen peroxide aqueous solutions of ammonium tellurate and characterized by single-crystal and powder X-ray diffraction analysis, by Raman spectroscopy and thermal analysis. The crystal structure of 1 comprises ammonium cations and a symmetric binuclear peroxotellurate anion [Te2 (μ-OO)2 (μ-O)O4 (OH)2 ](4-) . The structure of 2 consists of an unsymmetrical [Te2 (μ-OO)2 (μ-O)O5 (OH)](5-) anion, ammonium cations, hydrogen peroxide, and water. Peroxotellurate anions in both 1 and 2 contain a binuclear Te2 (μ-OO)2 (μ-O) fragment with one μ-oxo- and two μ-peroxo bridging groups. (125) Te NMR spectroscopic analysis shows that the peroxo bridged bitellurate anions are the dominant species in solution, with 3-40 %wt H2 O2 and for pH values above 9. DFT calculations of the peroxotellurate anion confirm its higher thermodynamic stability compared with those of the oxotellurate analogues. This is the first direct evidence for tellurium-peroxide coordination in any aqueous system and the first report of inorganic tellurium-peroxo complexes. General features common to all reported p-block element peroxides could be discerned by the characterization of aqueous and crystalline peroxotellurates.