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Paper degradation by iron gall ink is a challenging issue for the conservation of ancient manuscripts. It is usually attributed to both FeII catalyzed oxidation and acid catalyzed hydrolysis of cellulose, yet the dominant degradation pathway remains an open question. In this work, electron spin resonance spectroscopy (ESR) was used to identify radicals involved in cellulose degradation. Papers impregnated with iron salts were put in contact with an aqueous solution of DMPO (spin-trap) and analyzed by ESR. No DMPO–OHṖ adducts were detected while the addition of formate, an intermediary target molecule, led on the contrary to the detection of a significant amount of DMPO–CO2Ṗ− adducts. This reveals the predominant occurrence of reactive oxygen species (ROS) other than hydroxyl radicals (most likely superoxide or hydroperoxyl radicals). The production of DMPO–CO2Ṗ− adducts was found to be oxygen dependent and to originate mainly from ferrous ions lixiviated from the impregnated papers. At high iron loads (above 1 mmol L−1), it was shown that quantification of these adducts should be done with great care because of a competing formation of hydroxylamine that jeopardizes the ESR signal. Complementary TPA hydroxylation measurements performed by HPLC on ink and iron sulfate impregnated papers revealed some production of hydroxyl radicals but at a concentration several orders of magnitude below that of the ROS detected with formation of DMPO–CO2Ṗ− adducts. This HOṖ production was moreover not correlated with cellulose chain scissions, indicating that autooxidation by these radicals is not the main mechanism of cellulose depolymerisation in presence of iron gall ink. [ABSTRACT FROM AUTHOR]

A disposable microfluidic paper-based analytical device (μPAD) was developed to easily analyse different S-nitrosothiols (RSNOs) through colorimetric measurements. RSNOs are carriers of nitric oxide (NO) that play several physiological and physiopathological roles. The quantification of RSNOs relies on their decomposition using several protocols and the colorimetric detection of the final product, NO or nitrite. μPADs were fabricated by wax printing technology in a geometry containing one central zone for the sample inlet and eight circular detection zones interconnected by microfluidic channels for decomposition and posterior detection of decayed products. Different decomposition protocols including mercuric ions and light (UV, visible, and infrared) were tested on μPADs. For this purpose, a 3D printed holder was coupled with μPADs to easily design a simultaneous decomposition procedure using different light sources. The Griess reagent was added to detect NO and nitrite produced by the different decomposition methods. μPADs were then scanned using a flat board scanner and calibration curves based on color intensity were plotted. The limit of detection (LOD) values achieved for nitrite (used as a reference compound) and S-nitrosoglutathione (GSNO) using mercuric decomposition were 3 and 4 μM, respectively. The LOD reported herein for nitrite is considered among the lowest LODs already reported for this compound using μPADs. The results also show that low-molecular-weight RSNO, namely S-nitrosocysteine, decomposes more easily than high-molecular-weight RSNOs with light. As a proof of concept, RSNOs in human plasma were successfully detected on μPADs. For this purpose, a preliminary treatment step was optimized and the presence of high-molecular-weight (HMW) RSNOs was evidenced in the available plasma samples. The concentrations of HMW-RSNOs and nitrite in the various samples ranged from 5 to 16 μM and from 37 to 58 μM, respectively. [ABSTRACT FROM AUTHOR]

Minimally invasive desorption electrospray ionization-mass spectrometry (DESI-MS) and laser ablation electrospray ionization-MS (LAESI-MS) were used to look for soluble cellulose degradation products produced by accelerated aging in unsized cotton paper. Soluble extracts from papers aged 144 to 26 856 hours were first analyzed in solution using traditional electrospray ionization-MS (ESI-MS). Results were compared to those from direct analysis of condensed phase degradation products extracted from the absorbent paper substrate using DESI-MS and LAESI-MS. ESI-MS results showed evidence of oligosaccharide degradation products ranging from cellobiose to cellononaose; using DESI-MS and LAESI-MS, products from cellobiose to cellodecaose and glucose to cellooctaose, respectively, were observed. As degradation proceeded, increased quantities of both low and high molecular weight oligosaccharides were observed. The analytical approaches developed in the control study were applied for the detection of degradation products in two naturally-aged books dating from the 19th century, both made from cotton and linen. Oligosaccharides ranging from glucose to cellopentaose were observed. [ABSTRACT FROM AUTHOR]

Exploitation of hydrogen as an energy carrier requires the development of systems for its storage and delivery. Formic acid has been proposed as valuable hydrogen carrier compound, due to its relatively high hydrogen content (53 g L−1), the latter being easily and cleanly released in catalytic reactions under mild conditions (HCOOH → H2+ CO2). Ionic liquids are interesting solvents for homogeneous catalyzed formic acid decomposition systems as their extremely low volatility avoids solvent contamination of the produced hydrogen stream. In this paper an outstandingly simple, robust and active catalyst system is presented, namely RuCl3dissolved in 1-ethyl-2,3-dimethylimidazolium acetate (RuCl3/[EMMIM][OAc]). This system proved to be fully recyclable over 10 times. Turnover frequencies (TOF) of 150 h−1and 850 h−1were obtained at 80 °C and 120 °C, respectively. [ABSTRACT FROM AUTHOR]

Ionic liquids (ILs) are widely discussed as alternative green solvents not only because of their unique chemical properties, but also because of their extremely low vapour pressure and – at least in some cases – relatively high thermal stability. Two complementary methods are analyzed and compared to determine both the rate constant of decomposition and the vapour pressure of four ILs: (1) thermogravimetrical analysis at ambient pressure (TGap) with an overflow of inert gases, and (2) high vacuum (HV) experiments with a magnetic suspension balance (MSB). At ambient pressure, [EMIM][MeSO3] and [EMIM][CF3SO3] decompose without a significant contribution of evaporation, which leads to the rate constant of thermal degradation. For both ILs, the vapour pressure can only be determined at HV by the MSB, because the evaporation rate is then higher than the decomposition rate. For the relatively volatile ILs [EMIM][NTf2] and [BMIM][NTf2] the vapour pressure can be derived both by the MSB at HV as well as by TGap. General strategies to determine the volatility and stability of ILs and criteria for the maximum operation temperature with regard to decomposition and evaporation are presented. [ABSTRACT FROM AUTHOR]

Decomposition pathways of nucleoside α-hydroxyphosphonates 1(diastereomeric mixtures) bearing different aryl groups, both in the ester and the hydroxymethine fragment, were investigated under various hydrolytic conditions. We found that in aqueous basic media, the stability and decomposition pathways of these compounds were governed by the electronic features of the aryl group in the hydroxymethine moiety (hydroxyphosphonate H-phosphonate diester + aldehyde equilibria) and the nature of attacking nucleophiles (α-nucleophiles, e.g.hypoiodite or peroxide anions). The significant differences observed in the rates of hydrolysis of hydroxyphosphonates 1vs.their O-acylated derivatives point to the importance of an intramolecular acid catalysis exerted by the adjacent hydroxyl function. Based on these findings, an efficient synthetic protocol for otherwise difficult to access hydroxyphosphonate monoesters of type 7has been developed. [ABSTRACT FROM AUTHOR]

Diethyl cyanophosphonate (DCNP), a simulant of Tabun, is a common pollutant in pharmaceutical waste and poses a high risk to living organisms. Herein, we demonstrate a compartmental ligand-derived trinuclear zinc(II) cluster [Zn3(LH)2(CH3COO)2] as a probe for the selective detection and degradation of DCNP. It consists of two pentacoordinated Zn(II) [4.4.3.01,5]tridecane cages bridged through a hexacoordinated Zn(II) acetate unit. The structure of the cluster has been elucidated by spectrometric, spectroscopic, and single-crystal X-ray diffraction studies. The cluster shows a two-fold increased emission as compared to the compartmental ligand (at λexc = 370 nm and λem = 463 nm) due to the chelation-enhanced fluorescence effect and acts as a turn-off signal in the presence of DCNP. It can detect DCNP at nano levels up to 186 nM (LOD). The direct bond formation between DCNP and Zn(II) via the –CN group degrades it to inorganic phosphates. The mechanism of the interaction and degradation is supported by spectrofluorimetric experiments, NMR titration (1H and 31P), time of flight mass spectrometry and density functional theory calculations. The applicability of the probe has been further tested by the bio-imaging of zebrafish larvae, analysis of high-protein food products (meat and fish) and vapour phase detection by paper strips. [ABSTRACT FROM AUTHOR]

This paper presents a process for synthesising iron oxide nanoparticles modified with Cr(II), Cr(III) and Mn(II) ions and immobilised peroxidase. The obtained bionanocatalyst can be successfully applied to biocatalytic hydrogen peroxide decomposition reactions in pollutant removal processes. The iron oxide nanoparticles formed by Fe3O4 with Fe2O3 displayed sizes below 10 nm. The sorption capacities of the material for Cr(II), Cr(III) and Mn(II) ions were 8.81, 5.30, and 5.01 mg g−1, respectively. In the second step, after adsorption of the ions, the materials were subjected to peroxidase immobilisation processes, yielding biocatalysts with hydrogen peroxide degradation activities of, respectively 1.5, 2.1 and 1.4 units per mg. For H2O2 degradation, values of 27.9, 14.8, 20.4 and 0. 2 μg H2O2 per unit POX were achieved for Cr(II)/Fe3O4/Fe2O3/POX, Cr(III)/Fe3O4/Fe2O3/POX, Mn(II)/Fe3O4/Fe2O3/POX and pure peroxidase (POX), respectively, confirming the catalytic efficiency of the carrier-embedded enzyme, demonstrating that the developed method enhances the peroxidase efficiency. [ABSTRACT FROM AUTHOR]

The 1-methylallyl radical loses a hydrogen atom following photoexcitation to its lowest valence electronically excited state and displays statistical behavior in decomposition, implying that the presence of methyl rotors cannot be depended upon as an indicator for non-statistical dissociation dynamics in hydrocarbon radicals. [ABSTRACT FROM AUTHOR]

Given the enormous safety risks and environmental pollution that restrict the green development of isocyanate produced by phosgene reactions, we propose a new green and intrinsically safe route for synthesizing diisocyanates containing the furan ring from 5-hydroxymethylfurfural. In this work, the following novel reactions have been systematically investigated, including synthesizing a new compound methyl furan-2,5-dimethylene dicarbamate (FDC) using 2,5-bis(aminomethyl)furan (BAF) and dimethyl carbonate (DMC), the selective hydrogenation of FDC to a new compound methyl tetrahydrofuran-2,5-dimethylene dicarbamate (THFDC), and FDC and THFDC catalytic decomposition to produce corresponding furan-2,5-dimethylene diisocyanate (FDI) and tetrahydrofuran-2,5-dimethylene diisocyanate (THFDI). The results showed that CH3ONa could effectively catalyze the synthesis of FDC from BAF and DMC, and the separation yield of FDC was 98.1% under mild conditions including a nBAF : nDMC ratio of 1 : 10 at 70 °C for 4 h. CH3ONa can be recycled up to four times with high stability. A 0.5% Pd/γ-Al2O3 catalyst with low Pd loading was prepared, and it showed high catalytic activity and stability for FDC hydrogenation to THFDC, with a THFDC yield of 99.9% at 100 °C, 2 MPa H2 and 1 h, and the catalyst could be reused after simple treatment with ethanol. The structure–activity relationship of supported Pd catalysts was studied. The conditions for the thermal decomposition reactions of FDC and THFDC were optimized, resulting in FDI and THFDI yields as high as 89.6% and 92.8%, respectively. Owing to the urgent need for raw materials sustainability and environmental friendliness, the brand-new safe pathway for synthesizing FDI and THFDI was constructed, significantly improving the competitiveness of the non-phosgene method in preparing bio-based isocyanate. [ABSTRACT FROM AUTHOR]

Asymmetric organocatalysis has been recognized as one of the "top 10 emerging technologies" in chemistry by IUPAC in 2019. Its potential to make chemical processes more sustainable is promising, but there are still challenges that need to be addressed. Developing new and reliable enantioselective processes for reproducing batch reactions on a large scale requires a combination of chemical and technical solutions. In this manuscript, we combine a robust immobilized chiral phosphoric acid with a new packed-bed reactor design. This combination allows scaling up of the enantioselective addition of thiols to imines from a few milligrams to a multi-decagram scale in a continuous flow process without physical or chemical degradation of the catalyst. [ABSTRACT FROM AUTHOR]

Anhydride-cured epoxy is a common insulating material used in electrical equipment, but recycling it effectively is difficult, which results in the overall abandonment of the equipment after decommissioning and serious environmental pollution. In order to make anhydride cured epoxy degradable while maintaining its electrical performance, we synthesized a high-performance epoxy insulating material that can be recycled and reused using triethanolamine as a transesterification catalyst co-accelerator. Results show that the new epoxy has the lowest dielectric loss of 0.0012, the highest breakdown strength of 42.26 kV mm−1, and the highest tensile strength of 93.7 MPa. The degradable epoxy can be recovered via mechanical hot pressing and regenerated through chemical degradation. Degradation products can be directly used as curing accelerators to complete the re-preparation of the insulating material. Even after recovery, the properties of the epoxy resin meet the application requirements of insulating materials. [ABSTRACT FROM AUTHOR]

Room-temperature sodium–sulfur (Na–S) batteries hold great potential for next-generation energy storage devices due to their high theoretical energy density and low cost. However, the shuttling effect of sodium polysulfide (Na2Sn) species and the sluggish kinetics of the electrochemical conversion reaction greatly hamper the practical application of Na–S batteries. To address these challenges, by means of density functional theory (DFT) computations, we proposed two-dimensional metal chloride (MCl2, M = Mg and Ni) monolayers as multifunctional anchoring materials, including immobilizing soluble Na2Sn intermediates, boosting the reduction reaction of Na2Sn and the decomposition of Na2S species. Our results revealed that the NiCl2 monolayer can effectively immobilize the higher-order Na2Sn species with a stronger binding strength than the common electrolytes to prevent their dissolution. In particular, the NiCl2 substrate exhibits excellent electrocatalytic activity for the sulfur reduction reaction with a low free energy barrier (0.37 eV) and the Na2S decomposition reaction with a small kinetic barrier (0.45 eV), greatly lowering the energy barriers of Na2Sn conversions during discharge and charge and thus guaranteeing the fast redox kinetics and high sulfur utilization of Na–S batteries. Therefore, we predicted that NiCl2 monolayers can be utilized as a highly efficient multifunctional anchoring material for Na–S batteries. [ABSTRACT FROM AUTHOR]

An efficient strategy for the chemical degradation of polyurethane materials to recover polymerizable polyols has long been sought as a means of achieving green chemistry and circular resource utilization. However, this remains a major challenge. The present investigation endeavors to address this conundrum by delving into the intricacies of the multi-stage degradation (MSD) mechanism and successfully executing a gradient deconstruction of PUFs at low temperatures with minimal energy consumption. This approach involves a preliminary deconstruction of PUFs via ammonolysis, followed by deep depolymerization through acidolysis. The resulting recycled polyols (RPs) have high reactivity and can be used as a partial substitute for virgin polyol (up to 30 wt%) without purification treatment in the production of flexible PUFs. Furthermore, the MSD approach exhibits good adaptability and can be employed for the recycling of other types of PUFs, with the obtained RP being capable of up to 25 wt% VP substitution in the synthesis of new PUFs. Our research represents a significant advance in the development of efficient chemical degradation technologies for PUFs, which can support the transition to green chemistry and resource circularity. It provides valuable theoretical support for the industrialization of PUF degradation and upcycling. [ABSTRACT FROM AUTHOR]

Hydrazine and its derivatives can be used to recover plutonium and uranium from spent nuclear fuel as well as to obtain UO2 or mixed-oxide fuels. Uranium hydrazinates xUO3·yN2H4·zH2O have been synthesized, and their structural peculiarities and phase transitions upon heating have been investigated. It has been found that the elemental composition of U(VI) hydrazinate can be described as UO3·0.3N2H4·1.7H2O. It is a poorly crystalline layered compound with a crystallite size of (14 ± 3) nm, structurally similar to schoepite and ammonium polyuranates with neutral N2H4 molecules between layers of U(VI)-oxygen pentagonal bipyramids. U(VI) is present in the form of a linear UO22+ cation. In an inert atmosphere above 90 °C, xUO3·yN2H4·zH2O decomposes, resulting in partial U(VI) reduction due to the high mobility of hydrazine in the interlayer space or insufficient ratio of N2H4 to U(VI). The weak exothermic effect of the decomposition reaction and absence of combustible gases make the thermal treatment of xUO3·yN2H4·zH2O secure and applicable for nuclear technology. [ABSTRACT FROM AUTHOR]

Catalytic decomposition of hydrazine nitrate is a very important research topic in the environmental protection field. Herein, we used an Ru/C catalyst for the decomposition of hydrazine nitrate in HNO3, and the reaction kinetics and mechanism were studied in detail. The kinetics study of the decomposition of hydrazine nitrate (0.01 M) was conducted in the temperature range 313–343 K in 0.1 M HNO3 in the presence of Ru/C. The apparent activation energy for this reaction was 46.6 kJ mol−1 according to a fitting of the experimental data, while the reaction order was 1.5. It was also found that the reaction pathway of the catalytic decomposition of hydrazine nitrate on the Ru/C catalyst involved two processes: heterogeneous catalytic disproportionation of hydrazine nitrate at the catalyst surface and oxidation of hydrazine nitrate with catalytically generated HNO2. [ABSTRACT FROM AUTHOR]

The reactivity of two different phosphate esters has been explored with calcium ions. The reaction of calcium oxide with a mixture of mono/bis 2-ethylhexyl phosphate and 1,10-phenanthroline leads to the formation of the 1-D polymer [(phen)Ca(ehpH)2]n (1). On the other hand, the reaction of Ca(OAc)2 with trimethyl phosphate in the presence of 1,10-phenanthroline however yields needle-shaped colourless crystals of [(phen)Ca(OAc)2]n (2). Compounds 1 and 2 have been characterized by various spectroscopic and analytical techniques. The solid-state structures have been determined by single crystal X-ray diffraction studies. The arrangement of rigid and flexible parts in 1 makes it an interesting compound to be studied for its thermal behaviour. DSC experiments performed above and below room temperature reveal thermal transitions in both the ranges, where below room temperature transition is prominent. A combination of variable temperature powder and single crystal X-ray diffraction experiments provides further insights into these transitions. Solid-state bulk thermolysis of 1 at 500 °C leads to an amorphous material contaminated with graphitic carbon which upon further heating to 600 °C produces crystalline α-Ca(PO3)2. [ABSTRACT FROM AUTHOR]

Gas generation-based immunoassay is considered an attractive biosensing platform for the detection of biomarkers by incorporating the target recognition event with a catalyzed gas-generating reaction. Herein, an optical gas pressure sensor based on a silver/polydimethylsiloxane (Ag/PDMS) bilayer system was designed as a signal transducer to read the concentration of the detection target alpha-fetoprotein (AFP) quantitatively. In this proposed pressure-based assay, silicon dioxide (SiO2) nanospheres decorated with platinum (Pt) nanoparticles were coupled to detect antibodies by covalent linkage, and the captured antibodies were conjugated with magnetic beads via streptavidin-biotin interaction, simultaneously. When the AFP was loaded, the Pt-catalyzed hydrogen peroxide (H2O2) decomposition reaction was triggered to induce a significant increase in the reflectance signal of the Ag/PDMS bilayer gas pressure sensor (BGPS) due to a "wrinkled–specular" transition of the Ag film's surface. Under optimal conditions, the pressure-based biosensor exhibited a broad linear detection range from 0.05 to 132 ng mL−1 with a limit of detection (LOD) of 0.016 ng mL−1 for AFP, which satisfies the requirements for the clinical detection of AFP. Besides, the high specificity and detection accuracy of our Ag/PDMS BGPS also proved its feasibility for practical diagnosis. [ABSTRACT FROM AUTHOR]

In this paper, a two-step synthesis route combining an electrospinning technique and a solvothermal method has been accepted as a straightforward protocol for the exploitation of BiOCl–carbon nanofiber (CNF) hierarchical heterostructures. Photocatalytic tests showed that the BiOCl–CNF heterostructures possess a much higher degradation rate for 4-nitrophenol (4-NP) than pure BiOCl. The enhanced photocatalytic activity could be attributed to the effective separation of photogenerated carriers driven by the photoinduced potential difference generated at the BiOCl–CNF heterojunction interface. The OHṖ radicals played a critical role in the photocatalytic degradation of 4-NP over the BiOCl–CNF heterostructures. Moreover, the heterostructures could be recovered easily by sedimentation without a decrease in photocatalytic activity. [ABSTRACT FROM AUTHOR]

Monodisperse-porous Mn5O8 microspheres with multiple oxidation states were used as an efficient heterogeneous catalyst for the fast degradation of organic pollutants via peroxymonosulfate (PMS) activation. The presence of Mn(II), Mn(III), and Mn(IV) phases on the surface of the microspheres was shown by X-ray photoelectron spectroscopy. For the degradation studies, methylene blue (MB) and tetracycline (TC) were selected as the model organic pollutants. The removal process included both adsorption and chemical degradation stages for both pollutants. By using the Mn5O8–PMS system, complete removal of MB was achieved and 70% of TC was removed in a degradation period of 5 min. The high surface area originating from the porous nature and the crystalline phase found in the microspheres should provide very short removal periods with the selected pollutants. No significant change was observed in the removal behavior in the pH range of 3.3–9.0. The highest first order-rate constants were obtained as 0.961 min−1 and 0.570 min−1 for MB and TC, respectively. These values were approximately up to 24-fold higher with respect to similar degradation systems. The degradation runs performed using radical scavengers with the Mn5O8–PMS system demonstrated the presence of superoxide anion (O2*−) and singlet oxygen (1O2) radicals. The degradation efficiency decreased to 99.3% with MB and 89.3% with TC over five consecutive degradation runs. Final Mn concentrations lower than 0.14 ppm obtained at the end of the degradation runs demonstrated that monodisperse-porous Mn5O8 microspheres were a highly stable oxidation catalyst for the fast degradation of organic pollutants in an aqueous medium. [ABSTRACT FROM AUTHOR]

In this paper, one-dimensional W18O49 nanopowders were fabricated by a one-step solution combustion method using glycine as the fuel and a metal acid radical ion as the metal source. The morphologies and non-stoichiometric single-crystal phase of W18O49 can be controlled by changing the amount of the fuel. The nanoneedles had a large amount of defects such as oxygen vacancies. This characteristic resulted in an excellent visible light-driven photocatalytic performance that took about 50 min to degrade methylene blue (100 mL; 40 mg L−1) under visible light. The interesting reaction mechanism of such needle-like W18O49 and the photocatalytic mechanism are studied in this paper. [ABSTRACT FROM AUTHOR]

This paper reports the synthesis of monoclinic bismuth vanadate (BiVO4) by the oxidant peroxide method with crystallization under hydrothermal conditions, and its catalytic performance on the photodegradation of pollutants under visible light. The as-synthesized BiVO4 materials were characterized by means of X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), Raman spectroscopy, Ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS) and scanning electron microscopy (SEM). Hydrothermal treatment above 80 °C was required to obtain pure monoclinic BiVO4 phase by releasing V5+ ions from vanadium peroxo complexes. With the increase in hydrothermal reaction temperature, the particle size decreased. All BiVO4 samples presented large size and shape distribution and band gap of approximately 2.40 eV. The as-prepared BiVO4 catalysts showed high photoactivity for decomposition of model pollutants, methylene blue (MB) and rhodamine B (RhB) dyes, under exposure to visible light. The photodegradation mechanism was evaluated by adding scavengers, DMSO and KBrO3, which were used to probe ṖOH radical and conduction band (CB) electrons, respectively. It was observed that photodegradation of MB and RhB dyes is caused by the action of ṖOH radicals, and that BiVO4 CB electrons do not have reduction potential sufficiently high to reduce dissolved oxygen to O2−Ṗ. It was proven that the indirect mechanism, i.e.ṖOH radical formation, plays the major role on the BiVO4-assisted photodegradation process. [ABSTRACT FROM AUTHOR]

The effect of crystal growth morphology on impact sensitivity is described quantitatively. A simple theoretical background is presented to distinguish sensitive and insensitive materials with respect to their crystal habits. As a quantitative measure of impact sensitivity, crystal habit sphericity (Ψ) is introduced and the appropriate theoretical background is presented. The corresponding computational support for this approach is performed for 20 crystalline energetic salts based on 5,5′-bistetrazole derivatives, novel highperformance nitrogen-rich explosives. Along with the Ψ values, the corresponding decomposition temperatures, chemical hardness, energy content, and the average number of electrons per atom are also used in the regression equation yielding the sensitivity function Ω. A simple correlation of experimentally measured impact energies (in J) with the product ΨTdec² provides a rather good correlation coefficient (R² = 0.78), while the function Ω, comprising all the above-mentioned properties has better correlation (R² = 0.82). The maximum absolute deviation of the predicted impact energies does not exceed ±15 J. The mean and median of the differences between the predicted and experimental values equal zero and 0.5 J, respectively. [ABSTRACT FROM AUTHOR]

This paper presents a novel real-time impedance sensing chip for the evaporation detection of small volume solutions. Time sharing detection is performed for multiple sample measurements by a relay switching technique. In contrast to a conventional weight loss approach, the advantage of this proposed impedance sensing system is that it not only merely requires as little as 0.5 mL of test samples, but also provides high sensitivity and fast detection. More importantly, this proposed impedance sensing chip has advantages of a small chip size and easy decomposition for cleaning and reuse. [ABSTRACT FROM AUTHOR]

Photodegradation of organic dye molecules has attracted extensive attention because of their high toxicity to water resources. Compared with traditional UV-visible spectroscopy, SERS technology can reflect more sensitively the catalytic degradation process occurring on the surface of the catalysts. In this paper, we report the synthesis and structure of Fe3O4@SiO2@TiO2@Ag composite, which integrates SERS active Ag nanostructure with catalytically active titania. The degradation of the typical dye molecule crystal violet (CV), as an example, is investigated in the presence of the as-prepared Fe3O4@SiO2@TiO2@Ag composite structure, which exhibits high catalytic activity and good SERS performance. At the same time, renewable photocatalytic activity was also investigated. [ABSTRACT FROM AUTHOR]

All-nitrogen solids, if successfully synthesized, are ideal high-energy-density materials because they store a great amount of energy and produce only harmless N2 gas upon decomposition. Currently, the only method to obtain all-nitrogen solids is to apply high pressure to N2 crystals. However, products such as cg-N tend to decompose upon releasing the pressure. Compared to covalent solids, molecular crystals are more likely to remain stable during decompression because they can relax the strain by increasing the intermolecular distances. The challenge of such a route is to find a molecular crystal that can attain a favorable phase under elevated pressure. In this work, we show, by designing a novel N16 molecule (tripentazolylamine) and examining its crystal structures under a series of pressures, that the aromatic units and high molecular symmetry are the key factors to achieving an all-nitrogen molecular crystal. Density functional calculations and structural studies reveal that this new all-nitrogen molecular crystal exhibits a particularly slow enthalpy increase with pressure due to the highly efficient crystal packing of its highly symmetric molecules. Vibration mode calculations and molecular dynamics (MD) simulations show that N16 crystals are metastable at ambient pressure and could remain inactive up to 400 K. The initial reaction steps of the decomposition are calculated by following the pathway of the concerted excision of N2 from the N5 group as revealed by the MD simulations. [ABSTRACT FROM AUTHOR]

Trimethylaluminum is the most used aluminum precursor in atomic and molecular layer deposition (ALD/MLD). It provides high growth-per-cycle (GPC), is highly reactive and is relatively low cost. However, in the deposition of hybrid alucone films, TMA tends to infiltrate into the films requiring very long purge steps and thereby limiting the deposition rate (nm s−1) of the process. From our previous studies, we know that dimethylaluminum isopropoxide (DMAI) could be a potential candidate to substitute TMA in alucone depositions as it does not seem to infiltrate into the films. In this study, we perform a more detailed investigation of MLD of alucone on an atmospheric pressure spatial MLD system using DMAI as the aluminum precursor. The effect of deposition temperature and reactant purge times on the overall GPC has been investigated and a decreasing GPC with increasing deposition temperature and increasing EG purge time has been observed. Furthermore, the DMAI alucone films have been compared for their chemical environment and degradation with the films prepared using TMA and EG, showing striking similarities between the two. The results demonstrate that DMAI can be used as an alternative precursor to TMA for MLD of alucone films and this work can be used as a guide for designing efficient MLD processes in the future. [ABSTRACT FROM AUTHOR]

An effective and safe route is proposed to prepare supported Mo2C-based catalysts from organic–inorganic hybrids, which exhibit high activity and stability for producing H2from methanol catalytic decomposition. [ABSTRACT FROM AUTHOR]

An effective and safe route is proposed to prepare supported Mo2C-based catalysts from organic–inorganic hybrids, which exhibit high activity and stability for producing H2from methanol catalytic decomposition. [ABSTRACT FROM AUTHOR]

Polymeric carbon nitride (PCN) is an emerging metal-free photocatalyst with high stability but is plagued by low photocatalytic efficiency due to the rapid charge carrier recombination behavior. Herein, Bi-doped graphitic carbon nitride nanotubes (BCN nanotubes) with a porous structure have been facilely prepared by one-step thermal polymerization of mixtures of melamine, urea and bismuth nitrate pentahydrate under an Ar atmosphere. With unique structural advantages for charge carrier transfer, light harvesting, and large surface area, the as-prepared BCN nanotubes exhibit excellent photocatalytic activity for the degradation of Rhodamine (Rh) B with a 26.8-fold higher reaction rate than that of PCN under visible light irradiation. This work provides informative principles about the synthesis of PCN with controlled morphology and element doping simultaneously for the photocatalytic degradation of chemical pollutants. [ABSTRACT FROM AUTHOR]

The increasing amount of papers published on ionic liquids generates an extensive quantity of data. The thermal stability data of divergent ionic liquids are collected in this paper with attention to the experimental set-up. The influence and importance of the latter parameters are broadly addressed. Both ramped temperature and isothermal thermogravimetric analysis are discussed, along with state-of-the-art methods, such as TGA-MS and pyrolysis-GC. The strengths and weaknesses of the different methodologies known to date demonstrate that analysis methods should be in line with the application. The combination of data from advanced analysis methods allows us to obtain in-depth information on the degradation processes. Aided with computational methods, the kinetics and thermodynamics of thermal degradation are revealed piece by piece. The better understanding of the behaviour of ionic liquids at high temperature allows selective and application driven design, as well as mathematical prediction for engineering purposes. [ABSTRACT FROM AUTHOR]

The alignment of chromatographic peaks and deconvolution of overlapped peaks still remain challenges in the field of complex sample analysis. In this paper, we highlight a strategy that employs a new time shift alignment method derived from the well-known Rank Minimization method for aligning chromatographic peak shifts among samples and then uses trilinear decomposition methodology to interpret the overlapped chromatographic peaks in order to quantify analytes of interest. The performance of this novel strategy for chromatographic data analysis was evaluated using simulated chromatographic data as well as real chromatographic data. The results indicate that the new time shift alignment method can accurately correct time shifts in test samples even in the presence of unexpected interferences, and thus the low-rank trilinearity of the same analyte can be obtained, which will be helpful for trilinear decomposition to achieve the second-order advantage. Moreover, the results showed that this new alignment method is more automated in comparison with the Rank Minimization method and will be suitable for the alignment of the time shifts of analytes that are completely overlapped by coeluted interferences. [ABSTRACT FROM AUTHOR]

This work reports on the thermochemistry and kinetics of methyl propanoate (MePr) initial pyrolysis using the high ab initio multi-level composite W1 method over the temperature range 400–2000 K. Pyrolysis of MePr was simulated using ten complex bond fission reactions (R1–R10) and seven simple bond fission pathways (R11–R17). Rate coefficients of MePr decomposition have been estimated using transition state theory (TST) combined with tunneling through a one-dimensional Eckart barrier (Eck). Statistical Rice–Ramsperger–Kassel–Marcus (RRKM) tight theory has been also used in a pressure range of 0.001–100 atm. Our estimated rate coefficients are in strong agreement with previous literature and strongly pressure-dependent especially at high temperatures. In addition, thermodynamic parameters for MePr and some species involved in its decomposition reactions have been computed and compared with previous literature. [ABSTRACT FROM AUTHOR]

Heterogeneous photocatalytic systems have the potential to provide a green organic synthesis route for a number of industrially important chemicals. Issues remain with lack of selectivity. In this paper, a review is presented on achievements in this field. Parallels are drawn between systems optimised for heterogeneous photocatalytic organic degradation and heterogeneous catalytic organic synthesis. There is much fundamental knowledge that is still missing in this field of research. Parameters that can be manipulated are reaction solvent, pH, photon energy, chosen photocatalyst and its specific properties, and perhaps the use of more than one photocatalyst. Screening of photocatalysts for specific reactions and adapting the reaction conditions may achieve the best selectivity. Unlike the popular case of photocatalysts for organic degradation, the photocatalysts for organic synthesis should be highly customised on a case-by-case basis. Attention should be given to photocatalysts with the potential to be activated by the visible light spectrum, in order to achieve cost effectiveness of the heterogeneous photocatalytic organic synthesis. [ABSTRACT FROM AUTHOR]

Density functional theory (DFT) and a periodic slab model were used to study the geometric structure, electronic structure and dehydrogenation mechanism of ammonia adsorption on the MoN(0001) surface. The surface energy calculation results indicated that MoN(0001) terminated by N was the most stable surface. The NH3 molecule was preferably adsorbed at the top position through its lone pair electrons, while the most stable adsorption sites of NH2 and H were triple hcp sites, and NH and N were adsorbed at triple fcc sites. The results of transition state calculations showed that the decomposition reaction of ammonia mainly takes place through a step-by-step dehydrogenation mechanism of N2H4, and the compound desorption reaction of nitrogen was the rate limiting step of the whole reaction. The results of electronic structure calculations showed that the N2H4 molecule was adsorbed on the surface through the mixture of the 2Pz orbital of N and the 4dz2 orbital of Mo. With the progress of dehydrogenation, the charge transfer phenomenon became more and more obvious. It could be predicted that the charge transfer between the adsorbate and substrate played an important role in the catalytic process of accelerating the dehydrogenation of NH3. [ABSTRACT FROM AUTHOR]

Iron oxide (Fe2O3) nanoparticles encapsulated in the N-doped carbon framework (Fe2O3@C–N) were synthesized via a one-step thermal decomposition reaction of commercial C10H12FeN2NaO8 (ethylenediaminetetraacetic acid monosodium ferric salt), which can serve as the source of Fe, O, C, and N. As an anode material for lithium storage, the Fe2O3@C–N sample exhibits a reversible capacity of 1072 mA h g−1 after 200 cycles at 0.2 A g−1 and 553 mA h g−1 after 500 cycles at 0.5 A g−1. Furthermore, the synthetic strategy can be simply extended to prepare other similar products, e.g. MnO@C–N and ZnO@C–N. The MnO@C–N anode also shows good cycling performances (915 mA h g−1 after 200 cycles at 0.2 A g−1 and 768 mA h g−1 after 500 cycles at 0.5 A g−1). [ABSTRACT FROM AUTHOR]

Polymer-bonded explosives (PBX) are commonly-used form of energetic materials in weapon systems. However, the effects of polymers on the reactions and thermal decomposition of composites have rarely been investigated. In order to reveal the role of the interfacial polymers on the reaction mechanism and thermal sensitivity, reactive molecular dynamics (RMD) simulations were carried out using typical interface models for explosive crystals with polymers, and classic molecular dynamics simulations were also performed to investigate the interfacial interactions. The results show that the reactions and interaction energies are anisotropic along different crystalline directions, and not only the interfacial interactions but also the F-containing free radical reactions will influence the thermal sensitivity of the composite. This research is of significance for the design of advanced insensitive energetic composites. [ABSTRACT FROM AUTHOR]

In this work, an innovative analytical approach focused on the use of advanced imaging techniques for the chemical mapping of degradation and/or restoration products is proposed. A representative cross-section showing a very complex stratigraphy from the Saint Wilgefortis Triptych (Hieronymus Bosch), exhibited in the Galleria dell'Accademia di Venezia, was investigated. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) experiments were performed using a time-of-flight detector operating in the so-called delayed extraction mode. The time delay applied during the extraction of the secondary ions permitted mass spectra to be obtained with an excellent mass resolution and chemical maps with nanometer scale spatial resolution. The painting's cross-section was also analysed at the micrometer scale by micro-Fourier transform infrared spectroscopy (micro-FTIR). The combined analytical approaches highlighted the colocalization of lead chloride, oxychloride, and hydroxychloride ions, suggesting the transformation of lead white ((PbCO3)2Pb(OH)2) into laurionite (PbClOH). Furthermore, chlorine appears evenly diffused in the cinnabar (HgS) layer, inducing the alteration of its more external part into calomel (Hg2Cl2). In fact, from the chemical maps the presence in the sample of an unaltered portion of the cinnabar layer is evident. Such degradation products were probably due to the exposure of the painting to a chloride-rich atmosphere for a long time. This led to a global blackening of the painting. To protect the painting from aggressive chemical species, siloxane compounds were probably used as a modern restorative treatment. ToF-SIMS chemical maps revealed permeation of the silicon-based consolidants within the sample's cracks and no interaction products with the other constitutive materials of the painting were found. Finally, the presence of different lead soaps was detected in correspondence with the lead white layer. [ABSTRACT FROM AUTHOR]

The platinum core silica shell catalyst has facilitated stable sulfuric acid decomposition at high-temperature which was not possible over bare Pt nanoparticles due to sintering and agglomeration. Helium (He) gas supplies the heat (550–900 °C) in a high temperature gas cooled reactor (VHTR). The major challenge is designing a stable catalyst for the variable heat efficiency of He. Pt catalysts loaded on different supports, such as SiC, Al2O3, SiC-Al2O3, BaSO4, TiO2, SBA-15, and SiO2, have been extensively studied but they have not provided a simple method to form robust catalysts for sulfuric acid decomposition. The core–shell scheme, whereby nanoparticles are enclosed by protecting agents (CTAB) and are covered by a silica shell, delivered mesopores and exhibited higher activity and stability over testing for more than 100 h. TEM images confirmed that the Pt particles on the Pt@mSiO2 catalyst are more stable during sulfuric acid decomposition, and no significant evidence of agglomeration or sintering of the Pt core particles was found, despite some broken shells and dislocated Pt nanoparticles from the silica core. ICP-OES analysis of the spent catalysts after 100 h showed minimal Pt loss (9.0%). These types of catalysts are highly desirable for practical applications. [ABSTRACT FROM AUTHOR]

In this paper, one-dimensional W18O49 nanopowders were fabricated by a one-step solution combustion method using glycine as the fuel and a metal acid radical ion as the metal source. The morphologies and non-stoichiometric single-crystal phase of W18O49 can be controlled by changing the amount of the fuel. The nanoneedles had a large amount of defects such as oxygen vacancies. This characteristic resulted in an excellent visible light-driven photocatalytic performance that took about 50 min to degrade methylene blue (100 mL; 40 mg L−1) under visible light. The interesting reaction mechanism of such needle-like W18O49 and the photocatalytic mechanism are studied in this paper. [ABSTRACT FROM AUTHOR]

Both the solvent and catalyst play important roles in the chemoselective transformation of biomass-related compounds to fine chemicals and fuels. We report herein an innovative catalytic strategy for the direct valorization of xylose without external H2 producing high yield of furfuryl alcohol (FA), which is a versatile platform molecule. The solvent tert-butanol served not only as a precursor of the hydrogen honor, but also as a shield to facilitate xylose dehydration and inhibit the polymerization and decomposition reactions of FA. Commercial H4SiW12O40 was found to work as a multifunctional catalyst during the cascade conversion and had good reusability. The underlying catalytic mechanism revealed that the Brønsted and Lewis acid sites co-existed cooperatively to catalyze the xylose dehydration step and the active metal site of W atom adsorbed the hydrogen proton for the transfer hydrogenation of furfural to FA. After the incorporation of the formic acid as a supplemental hydrogen source, an unprecedented FA yield of 90% could be accomplished in a batch reactor under mild conditions. The kinetic behavior describing the conversion of xylose to FA was investigated to monitor the process. The estimated activation energies for xylose dehydration, furfural hydrogenation, and FA decomposition were 85.1, 78.8, and 101.1 kJ mol−1, respectively. This study opens a new avenue for the selective production of FA from hemicellulose-derived pentose in a green and straightforward manner. [ABSTRACT FROM AUTHOR]

We fabricate a hybrid 3D porous composite as an effective adsorbent for the removal of methylene blue (MB) dyes from aqueous solutions. In this hybrid composite, carbon nanotube (CNT) sponge grown by a chemical vapor deposition (CVD) method was utilized as a porous scaffold due to its large surface area. We decorated the surface of CNTs with a polydopamine layer in order to improve the hydrophilicity of CNT sponge (CNTS) and subsequently deposit silver nanoparticles (AgNPs) onto the surface of CNTs. The polydopamine layer acting as a strong binder plays a crucial role in the successful incorporation of AgNPs onto the surface of CNTs. AgNPs in composites act as a catalyst for the chemical degradation of MB dyes. The incorporation of AgNPs in the networks of CNTS provides a simple and efficient approach for recycling the adsorbents through the chemical reduction of MB dyes. Without the need to disperse CNTs in MB aqueous solutions and subsequently collect the CNTs with adsorbed MB molecules, CNT based composites as dye absorbents have the advantage of being efficiently recyclable. The presence of a polydopamine layer significantly improved the adsorption capacities in the networks of CNT-based composites due to the dramatic increase of wettability of CNTS in MB aqueous solutions. In addition, under an electric field the adsorption capacities of CNT-based composites are further improved and the adsorption kinetics of MB molecules are enhanced due to an increase of the diffusion rate of cationic MB dye in the networks of CNT-based composites. [ABSTRACT FROM AUTHOR]

Lipoyl-apocynin and lipoyl-sesamol are bio-active conjugates of thioctic acid (also known as alpha-lipoic acid), synthesized using a benign chemical approach via the combination of thioctic acid and the powerful bio-phytonutrients, apocynin and sesamol, respectively. Encapsulation was performed for chemically modified thioctic acid conjugates within a liposome structure as a possible drug carrier for targeted site delivery without chemical degradation, which could be useful in myeloperoxidase (MPO) mediated atherosclerotic cardiovascular disease (CVD) treatment. A facile processing route for the thioctic acid conjugates with the complete chemical characterization and bio-encapsulation of these chemical entities in a liposome sphere was developed, and analysis to establish the encapsulation efficiency, zeta potential, vesicle size, surface morphology, and long-term sustained stability was performed. The liposome conjugates were also characterized via critical in vitro experiments. The encapsulation efficiency of the thioctic acid conjugates was found to be almost 70%. In addition, the vesicle size and zeta potential were also measured for the formulated thioctic acid conjugates. The chromatographic evaluation of the encapsulated conjugates revealed that the liposomes seem to protect the thioctic acid conjugates when incubated in simulated body fluid, preventing ester hydrolysis, thereby offering chemical stability to the thioctic acid conjugates. The liposome loaded conjugates were also determined to be potent agents for MPO mediated atherosclerotic CVD in relevant preclinical in vitro tests. This is the first report of a highly efficient and sustainable chemical method for the liposomal encapsulation of thioctic acid conjugates of apocynin and sesamol that has been substantiated using relevant in vitro assays, and it could be useful for MPO-mediated atherosclerotic CVD treatment. [ABSTRACT FROM AUTHOR]

A truncated octahedron structured LiNi0.5Mn1.5O4 (denoted as EG-LNMO) is synthesized by a graphite assisted calcination method. Herein, we introduce a possible growth model, graphite–ethanol synergism, for the formation of the truncated octahedral morphology LiNi0.5Mn1.5O4 based on a series of experimental results. The electrochemical test results indicate that EG-LNMO materials exhibit excellent electrochemical performances, attributed to the unique truncated octahedron structure. It has a high stability {111} crystal plane group and high lithium conductivity {100} crystal plane group, which can meet the requirements of large rate and long cycling performance. Moreover, the electrochemical properties of EG-LNMO under extreme conditions are tested (rapid charge–discharge performance and cycling performance at high rate). The results show that the capacity decay of the electrode material mainly depends on the later stage of the cycling process, which may be ascribed to the synergistic effect of the electrolyte decomposition and corrosion reaction, as well as the phase change inactivation of the electrode material. [ABSTRACT FROM AUTHOR]

The present study describes the characterization of degradation products of cobicistat and atazanavir through mass spectrometry tools. Initially, cobicistat and atazanavir were subjected to stress degradation under different stress conditions. A single UPLC/PDA method was developed and applied separately for analysing the stressed samples of cobicistat and atazanavir. The degradation products were subjected to in-source fragmentation followed by collision-induced dissociations (CIDs) to produce further product ions simulating the MS3 step of ion-trap. This approach was applied to characterize five degradation products of cobicistat while the remaining degradation products of cobicistat and atazanavir were characterized by LC/QTOF/MS/MS experiments. Once the molecular weight of the degradation products was determined, various fragmentor voltages were applied to induce in-source fragmentation. These product ions were then further fragmented using conventional MS/MS, and the resulting spectra were analyzed to postulate the structures of rearranged product ions. All the data obtained from these studies provided valuable information on the fragmentation pathways of the degradation products of cobicistat and atazanavir. The developed UPLC/PDA method was validated with respect to the accuracy, precision, linearity, and robustness validation parameters. [ABSTRACT FROM AUTHOR]

In this work, we investigate the effect of the reaction environment and the in situ formation of an iron precursor on the synthesis of iron oxide nanoparticles (IONPs) through thermal decomposition. Spherical IONPs with a spinel Fe3−xO4 structure were synthesized reproducibly through the thermal decomposition of iron stearate (Fe(stearate)2) assisted by oleic acid in octyl ether or eicosene solvents under air. Under similar conditions and by adjusting only the reaction environment, namely under argon, core–shell FeO@Fe3−xO4 NPs with the same sizes were obtained. On the other hand, the thermal decomposition of iron oleate (Fe(oleate)3) in the presence of a mixture of oleic acid and sodium oleate, under air and argon, leads to the formation of cubic-shaped NPs with a similar FeO@Fe3−xO4 structure. Cubic NPs with a homogenous Fe3−xO4 composition were synthesized from the iron oleate formed in situ from FeCl3·6H2O and sodium oleate reactants, which was immediately decomposed. The composition and shape dependence on the experimental conditions, i.e. atmosphere and iron complex, is discussed. The synthesized NPs were characterized by combining several techniques including transmission electron microscopy (TEM), scanning-TEM, X-ray diffraction (XRD) and 57Fe Mössbauer spectrometry. The correlation between the crystalline composition and the magnetic properties was investigated by carrying out magnetization measurements as a function of the applied field and temperature. The spherical and cubic-shaped NPs with a core–shell structure display exchange bias coupling due to the interaction between the antiferromagnetic (AFM) core and the ferrimagnetic (FiM) layer at the surface, while the Fe3−xO4 NPs exhibit a saturation magnetisation lower than that for the bulk counterpart due to the oxidation effects and the presence of a spin canted layer at their surface. [ABSTRACT FROM AUTHOR]

rGO–Fe2O3 composites were prepared using different solvents (distilled water, ethanol, N-methylpyrrolidone, ethyl acetate, n-butyl alcohol and N,N-dimethylformamide) via a simple solvothermal method and characterized by SEM, TEM, XRD, FT-IR, Raman and XPS techniques. Then, the catalytic action of rGO–Fe2O3 composites (prepared in different solvents), GO, rGO and pristine Fe2O3 on the thermal decomposition of ammonium perchlorate (AP) were studied using a TG-DSC instrument. DSC results showed that GO, rGO, pristine Fe2O3 and rGO–Fe2O3 composites could effectively promote the thermal decomposition of AP. Additionally, rGO–Fe2O3 fabricated in N,N-dimethylformamide (DMF) solvent possesses the best catalytic performance among the investigated materials. This result can be attributed to the better dispersibility of Fe2O3 nanoparticles on graphene oxide prepared in DMF solvent, which was confirmed by SEM and TEM imaging. The high temperature decomposition exothermic peak (HTP) and the apparent activation energy of AP are reduced by 119.6 °C and 173.3 kJ mol−1, respectively, in the presence of Fe2O3–rGO (DMF) composite. [ABSTRACT FROM AUTHOR]

High-performance cobalt ferrite nanoparticles (CoFe2O4 NPs) with controlled morphology were obtained by an economical and simple thermal decomposition technique. Cube-shaped CoFe2O4 NPs with different particle dimensions were achieved by precisely controlling the reaction refluxing time. The size-dependent magnetic properties were investigated and reported. The coercivity (Hc) of CoFe2O4 NPs increased with particle size upto single domain limit. Higher coercivity (Hc) values of 17 132 Oe and 3364 Oe with excellent remanent magnetization (Mr) values of 76.0 and 61.05 emu g−1 at 10 K and room temperature were obtained for CF-4 NPs (∼35 nm). The excellent remanent magnetization and high coercivity of CF-4 NPs led to a high energy product (BH)max of 2.41 MGOe (19.2 kJ m−3) at room temperature, which is the highest reported value to date for CoFe2O4 NPs to the best of our knowledge. The excellent magnetic properties indicated the capabilities of CoFe2O4 NPs in permanent magnets for current technological applications. [ABSTRACT FROM AUTHOR]

Environmental pollutants cause harm to animals, humans, and ecosystems worldwide, and powerful approaches are urgently needed to address this challenge. Dye degradation photocatalysis is one of the most promising methods for the chemical breakdown of organic pollutants. The large specific surface area produced by nanotechnology significantly improves photocatalytic performance. In the wave of full-fledged research on photocatalytic nanoparticles, there is a higher demand for unique means of characterization, such as real-time growth diagnosis and precise phase modulation of the particles. The advantages of laser spectroscopy are its non-contact methodology, rapid response, and accurate directionality, and therefore, spectral characterization methods are becoming more suitable for the real-time diagnosis of photocatalysts. In this review, traditional and spectroscopic means of characterizing dye degradation photocatalytic nanoparticles were examined. In addition, laser spectroscopic characterization can be performed using PL, LCRS, LSPR, SERS, UTAS, and LIBS, which were introduced in this review. Notably, the regulation applicability of LSPR and SERS with noble metal-based nanoparticles and the real-time flexibility of UTAS and LIBS are advantages during the use of laser spectroscopy to examine nanocomposites of photocatalysis. Moreover, the future development of laser spectroscopy for photocatalytic nanoparticle characterization was discussed. [ABSTRACT FROM AUTHOR]

In order to develop high energy density materials, 5,5′-dinitramino-3,3′-bi(1,2,4-oxadiazole) (3, DNABO), a new heterocyclic energetic compound, was synthesized by the simple nitration of 5,5′-diamino-3,3′-bi(1,2,4-oxadiazole) (2) with 95% fuming nitric acid. By treating compound 3 with two equivalents of energetic bases or their salts, a series of energetic salts 4–10 based on nitrogen-rich cations were readily obtained. Among them, the hydroxylammonium salt (5) shows the best comprehensive properties (5: d = 1.879 g cm−3; Td = 190 °C; P = 36.2 GPa; vD = 8916 m s−1). In addition, the guanidinium salt (7) possesses excellent thermal stability with an onset decomposition temperature of 317 °C. [ABSTRACT FROM AUTHOR]