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The development of heterogeneous Fenton catalysts with good performance and stability is a challenge in the field of wastewater treatment. In this work, MgAlFe hydrotalcite-like compounds (MgAlFe-HTLcs) were prepared by solid phase reaction at room temperature and modified via a hydrothermal process. The experimental results showed that MgAlFe-HTLcs had a good layered structure with the same proportion of iron and aluminium, 18 h of crystallisation time and 110°C of crystallisation temperature and the lamellar structure was more uniform by solid grinding. Furthermore, the addition of iron can activate H2O2 more effectively to generate active oxygen which is •OH. The degradation experiments demonstrated that nearly 99.0% degradation efficiency was achieved for 10 mg/L Malachite Green (MG) solution within 60 min at the conditions of 0.10 g·L−1 MgAlFe-HTLcs, 0.10 mol·L-1 H2O2 and a natural pH of 6.3. Total organic carbon (TOC) removal reached 72.2% in a 70 min reaction. BET and XRD were measured to further discuss the stability and durability. Finally, a possible mechanism for the degradation of MG was presumed. [ABSTRACT FROM AUTHOR]

Development of high performance room temperature sensors remains a grand challenge for high demand of practical application. Metal oxide semiconductors (MOSs) have many advantages over others due to their easy functionalization, high surface area, and low cost. However, they typically need a high work temperature during sensing process. Here, p-type sensing layer is reported, consisting of pore-rich dumbbell-like Co 3 O 4 particles (DP-Co 3 O 4 ) with intrinsic high catalytic activity. The gas sensor (GS) based DP-Co 3 O 4 catalyst exhibits ultrahigh NH 3 sensing activity along with excellent stability over other structure based NH 3 GSs in room temperature work environment. In addition, the unique structure of DP-Co 3 O 4 with pore-rich and high catalytic activity endows fast gas diffusion rate and high sensitivity at room temperature. Taken together, the findings in this work highlight the merit of integrating highly active materials in p-type materials, offering a framework to develop high-sensitivity room temperature sensing platforms. [ABSTRACT FROM AUTHOR]

The aramid fabric ( AF)-reinforced polyimide ( PI) composites filled with carbon black ( CB) were fabricated by means of a thermal imidization and their mechanical, thermal and electrochemical behaviors were comparatively investigated. Experimental results showed that the tensile strength of composite increased with an increase of the CB, meanwhile, the addition of 5 wt% CB and AF increased the tensile modulus to 5682.0 MPa. The superior mechanical properties of the composites were attributed to the good dispersion and effective stress transfer between the polymer and CB, as evidenced by the results from X-ray diffraction ( XRD) and morphological studies. Besides, the thermal-nonoxidative stability of PI was significantly improved by the incorporation of CB and AF. Furthermore, the CB/ AF/ PI composite was employed as the supercapacitor electrode in the 6 mol/L KOH aqueous electrolyte solution, which exhibited a specific capacitance of 510 F•g−1 at 10 mV•s−1. It also exhibited excellent long-term stability, and the energy density was stable with the increase in the power density. The super performance of the composite electrode is attributed to the synergistic effects of CB particles and organic polymer. [ABSTRACT FROM AUTHOR]

New energetic materials, [Ca(MCZ)3(H2O)2](ClO4)2and {[Ba2(MCZ)4(H2O)2(μ1-ClO4)2(μ2-ClO4)2]0.5}n, are synthesized and tried as alternatives to common primary explosives. Both the crystal structures were determined by single-crystal X-ray diffraction. The crystal of [Ca(MCZ)3(H2O)2](ClO4)2belongs to the monoclinic, P21/c space group,a = 14.168(3) Å,b = 8.5938(18) Å,c = 18.889(4) Å,β = 111.234(2)°,V = 2143.8(8) Å3,ρ = 1.6893 g cm−3, and {[Ba2(MCZ)4(H2O)2(μ1-ClO4)2(μ2-ClO4)2]0.5}nbelongs to the triclinic, P-1 space group,a = 7.166(2) Å,b = 10.461(2) Å,c = 11.738(4) Å,α = 110.563(5)°,β = 93.799(2)°,γ = 96.864(3)°,V = 812.4(4) Å3,ρ = 2.185 g cm−3. Their thermal stabilities were investigated by differential scanning calorimetry (DSC), and exothermic peak temperatures with a heating rate of 10 °C min−1are 249.7 and 181.7 °C, respectively. Non-isothermal reaction kinetics parameters were calculated via both Kissinger’s method and Ozawa-Doyle’s method to work outEK = 124.6 kJ mol−1, lgAK = 10.38,EO = 126.7 kJ mol−1for the calcium complex andEK = 100.3 kJ mol−1, lgAK = 9.50,EO = 102.6 kJ mol−1for the barium complex. Additionally, the critical temperatures of thermal explosion, ΔS≠, ΔH≠, and ΔG≠were calculated as −231.2 J K−1 mol−1, 120.417 kJ mol−1, 236.728 kJ mol−1for the calcium complex and −230.6 J K−1 mol−1, 96.723 kJ mol−1, 195.938 kJ mol−1for the barium complex. As for their explosive nature, sensitivities toward impact and friction were tested. Both [Ca(MCZ)3(H2O)2](ClO4)2and {[Ba2(MCZ)4(H2O)2(μ1-ClO4)2(μ2-ClO4)2]0.5}nare insensitive to friction (>360 N); their impact sensitivities are acceptable (20 and 13 J). Both compounds are energetic complexes. [ABSTRACT FROM PUBLISHER]

Five kinds of graphene nanoplatelet-modified explosive lead styphnate composites (GLS) have been synthesized with different GNPs content from 0.1 to 2.0 mass% and characterized by SEM, XRD and Raman spectra. The initial thermal decomposition behaviours were studied by DPTA, and the complete thermal decompositions were studied by DSC and TG for the everlasting thermal stability of explosives in storage and application. The effects of GNP contents on thermal decomposition were investigated. The evolved gas amount from DPTA test indicates that GLS 1.0 % has the best thermal stability at ambient storage conditions. According to TG and DSC tests, the characteristic temperatures of thermal decomposition ( T and T), the thermodynamic parameters (Δ S, Δ H and Δ G), the kinetic parameters ( E and A) also confirmed this view. The results indicate that the GNP plays two opposite roles in their thermal decomposition processes, the catalysis reaction and hindering thermal conduction. [ABSTRACT FROM AUTHOR]

Two new ionic complexes, (DATr)2[Li2(TNR)2·2H2O]·2H2O (1) and (DATr)[Zn(DATr)Cl3] (2), were synthesized by using 3,4-diamino-1,2,4-triazole (DATr) as outer cation. X-ray single-crystal diffraction analysis revealed that the two complexes crystallize in triclinic and orthorhombic crystal systems, respectively. Differential scanning calorimetry was applied to assess the thermal decomposition behavior and kinetic parameters of decomposition were studied by using Kissinger’s and Ozawa–Doyle’s methods. Furthermore, the critical temperature of thermal explosion and parameters of thermodynamics were obtained. [ABSTRACT FROM PUBLISHER]

Both [Cu(DAT)2(PA)2] (1) and [Cu(DAT)2(HTNR)2] (2) were prepared from 1,5-diaminotetrazole (DAT) and copper trinitrophenol,1for picrate (PA) and2for styphnate acid (2,4,6-trinitro resorcinol, TNR), and were characterized by elemental analysis, FT-IR spectroscopy, and single crystal X-ray diffraction. The space group of these compounds isP21/c(monoclinic). The lattice parameters are similar [a = 11.405(3) Å,b = 14.867(3) Å,c = 8.099(2) Å for1anda = 12.262(3) Å,b = 14.900(3) Å,c = 7.243(2) Å for2], except theβ = 106.257(3)° in1andβ = 92.989(4)° in2. Both have extended structures due to hydrogen bonds, but there are some differences because of the ligands induced effect. Differential scanning calorimetry analysis shows that two exothermic processes take place in both complexes, the first peak temperatures are 488.2 K for1and 519.2 K for2. The kinetic parameters of the first exothermic process were studied by using Kissinger’s method and Ozawa’s method, in which the enthalpy of formation (−7346 and −5706 kJ M−1), critical temperature of thermal explosion (475.0 and 515.8 K), entropy of activation (ΔS≠), enthalpy of activation (ΔH≠), and free energy of activation (ΔG≠) were calculated and obtained as −117.25 J K−1 M−1, 140.64 kJ M−1, 196.44 kJ M−1and −219.1 J K−1 M−1, 383.56 kJ M−1, 495.34 kJ M−1for1and2, respectively. The sensitivity test results showed that both compounds were sensitive to impact (<5 J) and flame (>20 cm) rather than friction. Two similar complexes combined with 1,5-diaminotetrazole (DAT) and copper trinitrophenol were characterized by elemental analysis, FT-IR spectroscopy and single crystal X-ray diffraction and the sensitivity were studied. [ABSTRACT FROM AUTHOR]

The single crystal structure of 1,1′-bis (3,5-dimethyl-pyrazole) methenehydrazine (BDM) was determined by X-ray single crystal diffraction for the first time. The obtained experimental results indicated that BDM was the of 3,6-bis(3,5-dimethylpyrazol-1-yl)-1,4-dihydro-1,2,4,5-tetrazine (BDT), which was the key precursor of s-tetrazine. By this evidence, the preparation mechanism of BDT was proved: At 318.15 K, triaminoguanidine and pentanedione reacted to achieve the (BDM) by molecular and ; when heated to 363.15 K, BDT was then generated by two molecules of BDM with reaction. Furthermore, the properties and also the non-isothermal kinetic parameters have been investigated in the present work. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • In this work, the obtained Zn 2 SnO 4 -RGO hybrids exhibited outstanding sensing performance for detecting oxidizing gases (NO 2 and O 3) with very low cross sensitivities to reducing gases, such as C 2 H 5 OH, CH 3 COCH 3 and CO. • The Zn 2 SnO 4 -RGO based sensors exhibited high response values of up to 3.50 for 500 ppb NO 2 , which is higher than that for detection of 500 ppb O 3 (1.78) at 30 °C under 50% relative humidity (RH). • The surface reaction between Zn 2 SnO 4 -RGO hybrids and NO 2 can be concluded from Operando diffuse reflectance infrared Fourier transformed spectroscopy (Operando DRIFT). Abstract Highly selective oxidizing gas sensors are of great importance for environmental pollution monitoring. In this work, a hybrid material containing Zn 2 SnO 4 nanoparticles (NPs) and immobilized reduced graphene oxide (Zn 2 SnO 4 -RGO) was developed as a high performance gas sensing material for the detection of ppb-levels of oxidizing gases (NO 2 and O 3). The structural, morphological and compositional properties of the Zn 2 SnO 4 -RGO hybrids were systematically characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS), which demonstrated the successful anchoring of Zn 2 SnO 4 NPs on RGO nanosheets. The obtained Zn 2 SnO 4 -RGO hybrids exhibited outstanding sensing performance for detecting oxidizing gases (NO 2 and O 3) with very low cross sensitivities to reducing gases, such as C 2 H 5 OH, CH 3 COCH 3 and CO. The Zn 2 SnO 4 -RGO based sensors exhibited high response values of up to 3.50 for 500 ppb NO 2 , which is higher than that for detection of 500 ppb O 3 (1.78) at 30 °C under 50% relative humidity (RH). Moreover, the NO 2 sensing performances of Zn 2 SnO 4 -RGO-based sensors were investigated under various RH. In all cases, the sensors based on RGO and Zn 2 SnO 4 -RGO hybrids presented p-type behavior. The sensors based on Zn 2 SnO 4 -RGO hybrids also exhibited high response values of up to 3.62 for 1 ppm NO 2 at 50 °C in 80% RH, which is much higher than that of pure RGO (1.31). The excellent sensing performances are mainly ascribed to the synergetic effect of Zn 2 SnO 4 NPs and RGO. Furthermore, the surface reaction between Zn 2 SnO 4 -RGO hybrids and NO 2 can be concluded from Operando diffuse reflectance infrared Fourier transformed spectroscopy (Operando DRIFT). [ABSTRACT FROM AUTHOR]

Doping and high specific area are essential to the performance of supercapacitor electrode materials. However, the conventional single doping in two dimensional electrode materials is still unable to get high supercapacitive performance. Here we report a facile hydrothermal process using ammonia as a source of nitrogen (N) and thiourea as a sulfur (S) source to prepare N/S co-doped three dimensional (3D) graphene hydrogel (N/S-3DGH) for supercapacitor electrode application. The as-prepared N/S-3DGH is uniform and stable. The N/S co-doped 3DGH electrode material exhibits a high specific capacity of 1063 Cg -1 at a current density of 1 Ag -1 . Even at a density of 20 Ag -1 , it can still hold an excellent charge and discharge cycling stability, and with 76% of initial capacity retained after 6000 charge and discharge cycles at a density of 10 Ag -1 . Moreover, the all-symmetric solid-state supercapacitor fabricated by N/S-3DGH without any binders owned an energy density of 6.25 Wh kg −1 at a power density of 500 W kg −1 showing very promising applications for portable power and flexible energy storage devices. [ABSTRACT FROM AUTHOR]

In this work, core-shell WO 3 -SnO 2 (CS-WS) nanofibers (NFs) have been successfully synthesized via a coaxial electrospinning approach. The structure and morphology characteristics of the resultant products were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectra (XPS). To investigate the sensing mechanism of the CS-WS NFs, sensors based on SnO 2 NFs, WO 3 NFs, and SnO 2 -WO 3 composite NFs were fabricated respectively, and their gas sensing properties were investigated by using CO, ethanol, toluene, acetone, and ammonia as the test gas. The results indicated that the CS-WS NFs exhibited a good response to ethanol (5.09 at 10 ppm) and short response/recovery time (18.5 s and 282 s) compared with the other test gases. The enhanced ethanol sensing properties of CS-WS NFs compared with those of SnO 2 NFs were closely associated with the CS structure and its derivative effect due to the different work function of SnO 2 and WO 3 . The approach proposed in this study may contribute to the realization of more sensitive metal oxide semiconductor (MOS) core-shell heterostructure sensors. [ABSTRACT FROM AUTHOR]

Transition metal oxides have attracted considerable attention as anode materials of lithium-ion batteries (LIBs). However, poor electrical conductivity and huge volume change hinder their practical application. Porous nanostructure is vital to attain high-performance lithium-ion batteries. Herein, we have designed and fabricated regularly porous ZnFe 2 O 4 nanospheres consisted of small primary nanoparticles via a facile hydrothermal method followed by calcination. The structural properties and morphology of the sample are characterized by powder X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy and X-ray photoelectron spectroscopy. The composite is then evaluated as anode for Li-ion battery and shows excellent electrochemical properties. The reversible capacity of 868.9 mAh g −1 can be obtained at 200 mA g −1 over 80 cycles. Furthermore, the discharge capacity can still retain 456 mAh g −1 after 600 cycles at a high charge rate of 2 A g −1 . Our findings reveal that ZnFe 2 O 4 sample is a promising anode material for LIBs due to its superior rate capability and long cycle life. [ABSTRACT FROM AUTHOR]

Magnesium azotetrazole-1,1'-dioxide (1) was first prepared and intensively characterized by single-crystal X-ray diffraction, IR spectroscopy, mass spectrometry, elemental analysis, and DSC measurements. The heat of formation was calculated using the atomization energy method based on quantum chemistry and the heat of detonation was also predicted. The NBO analysis was performed for inspecting charge distributions. The sensitivities towards impact and friction were tested using the BAM standard. The high detonation performance (5289 kJ·kg-1), good thermal stabilities (245.5 °C) and excellent insensitivity (39.2 J and >360 N) as well as clean decomposition products supports it of great interest as a promising candidate of green insensitive energetic materials. [ABSTRACT FROM AUTHOR]

A reticular 3D energetic metal-organic framework, sodium 1,1′-dinitramino-5,5′-bistetrazolate was first synthesized and fully characterized by crystal X-ray diffraction, elemental analysis, mass spectrometry, IR spectroscopy, differential scanning calorimetry (DSC) and sensitivity test. It shows a density of 1.892 g·cm −3 , a positive oxygen balance and a high decomposition temperature of 250 °C. The promising energetic properties were also investigated by using theoretical calculation methods. Its calculated heat of formation (529.5 kJ·mol −1 ) combined with impressive heat of detonation (5080 kJ·kg −1 ), good thermal stabilities and clean detonation products make it a competitive replacement as a green energetic material. [ABSTRACT FROM AUTHOR]

Pt-loaded mesoporous WO 3 was fabricated by nanocasting method. Mesoporous structure provided ordered tunnel which was convenient for gas diffusion and the large specific surface area which could offer more active sites. The noble metal (Pt) improved the catalytic efficiency which played crucial role in enhancing the performance of the gas sensor. The obtained materials were characterized by X-ray diffraction (XRD), Brunauer-Emmet-Teller (BET), Transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Characterization indicated that the synthesized materials had ordered mesoporous structure with excellent crystallinity and the pore size was about 10.6 nm. Static test system was employed to measure ammonia sensing properties for the as-prepared samples. The sensor based on Pt-loaded WO 3 presented higher sensitivity, quicker response-recovery rates, excellent repeatability and selectivity. It indicated that the Pt-loaded mesoporous WO 3 was a potential ammonia gas sensor material. [ABSTRACT FROM AUTHOR]

The development of graphene-based room temperature gas sensors has drawn massive attention due to their unique advantage of gas sensing at room temperature. In this paper, in pursuit of developing high-performance graphene-based gas sensors, a NO 2 gas sensor has been successfully fabricated using sulfonated reduced graphene oxide (S-rGO) anchoring with SnO 2 nanoparticles as sensing materials. The SnO 2 nanoparticles modified S-rGO (SnO 2 /S-rGO) hybrids were prepared by deposition of SnO 2 nanoparticles on the surface of S-rGO through hydrothermal synthesis method. The combined characterizations of X-ray diffraction, UV–vis spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, energy-dispersive spectroscopy, as well as N 2 sorption isotherm indicate the successful preparation of SnO 2 /S-rGO hybrids with porous structure. Most importantly, SnO 2 /S-rGO hybrids exhibit good sensing performances for detection of NO 2 at room temperature, such as high response, fast response and recovery rate, and good selectivity. The sensor based on SnO 2 /S-rGO hybrids exhibits better sensing performances than the previously reported rGO-based gas sensors. Furthermore, the excellent sensing performances of sensor based on SnO 2 /S-rGO also render it suitable for development of high performance gas sensors operated at room temperature. [ABSTRACT FROM AUTHOR]

Through a one-pot reaction of NiCO3 ·2Ni(OH)2 ·H2O, aminourea hydrochloride (SCZ ·HCl) and 2,4,6-trinitroresorcinol (TNR), a halogen-free and lead-free chelating energetic material (CEM) [Ni(SCZ)3]TNR was synthesized. We confirmed the structure of [Ni(SCZ)3]TNR by infrared spectroscopy, X-ray diffraction, and elemental analysis. The complex is triclinic with P $\bar{1}$(2)/ n space group. Cell parameters are: a = 1.04008(17) nm, b = 1.3719(2) nm, c = 1.4897(2) nm, V = 2.0337(6) nm3, Z = 4. The central nickel atom is six-coordinate with three oxygen atoms of carbonyl groups and three terminal nitrogen atoms of the hydrazine groups from three SCZs to form a distorted octahedron. Differential scanning calorimetry and analysis applied to assess the thermal decomposition behavior. The DSC curve with a linear heating rate of 10 °C ·min-1 shows that [Ni(SCZ)3]TNR is thermally stable with one exothermic peak temperatures of 78.8 °C and two exothermic peak temperatures of 216.8 °C and 308.1 °C. The kinetic parameters were obtained by non-isothermal reaction kinetics. The equation can be expressed as ln k = 24.49-243.3 × 103/ RT. Moreover, the values of the critical temperature of thermal explosion, Δ S≠, Δ H≠, Δ G≠, and the enthalpies of formation were obtained as 206.5 °C, -145.543 J ·mol-1 ·K-1, 237.18 kJ ·mol-1, 305.84 kJ ·mol-1, and -2.65 MJ ·kg-1, respectively. [ABSTRACT FROM AUTHOR]

The heptacoordinate transition metal coordination compound [Cd(SCZ)3(H2O)](PA)2 ·3H2O ( 1) with the ligand semicarbazide (SCZ) and the counteranion picrate (PA) was synthesized and characterized by elemental analysis and FTIR spectroscopy. Single-crystal X-ray diffraction analysis revealed that 1 crystallizes in the monoclinic space group P21/ c. The Cd2+ ion is heptacoordinated by three SCZ groups and a water molecule. SCZ presents typical bidentate coordination modes. The thermal decomposition mechanism of 1 was studied by differential scanning calorimetry (DSC), which revealed that complex 1 exhibits three small endothermic and two large exothermic processes. The non-isothermal kinetics parameters were calculated by the Kissinger's method and Ozawa-Doyle's method, respectively. The heat of combustion was measured by oxygen bomb calorimetry. The enthalpy of formation, the critical temperature of thermal explosion, the entropy of activation (Δ S≠), the enthalpy of activation (Δ H≠), and the free energy of activation (Δ G≠) were also calculated. Sensitivity tests revealed that 1 is insensitive to mechanical stimuli. [ABSTRACT FROM AUTHOR]

Lithium chloride (LiCl)-loaded 3D cubic mesoporous silica KIT-6 (LiCl-KIT-6) composites were prepared as resistance-type humidity-sensitive materials. The structures of the resultant composites were characterized by X-ray diffraction, N 2 adsorption–desorption, and transmission electron microscopy. The humidity sensors based on LiCl-KIT-6 composites were fabricated and the sensing properties were investigated. Results indicate the uniform pore distribution of KIT-6 contributes to the rapid hydrone transport in mesoporous channels. The impedance of optimized 3 wt% LiCl-KIT-6 sensor changed by more than three orders of magnitude over the relative humidity range of 11–95%. The response and recovery times of the sensor were 15 s and 28 s, respectively. Finally, the complex impedance method was used to analyze the humidity sensing mechanism of the sensor based on LiCl-KIT-6. [ABSTRACT FROM AUTHOR]

A facile and effective strategy has been successfully developed to synthesize reduced graphene oxide-multiwalled carbon nanotubes-tin oxide nanoparticles (rGO-CNT-SnO 2 ) hybrids by hydrothermal method. The combined characterizations of X-ray diffraction, Raman spectrum and Transmission electron microscopy were used to characterize the samples thus obtained, indicating the successful preparation of rGO-CNT-SnO 2 hybrids. A room temperature NO 2 sensor was fabricated by dropping the dispersion of rGO-CNT-SnO 2 hybrids on the surface of ceramic substrate previously printed Au electrodes. Most importantly, the sensor based on rGO-CNT-SnO 2 hybrids shows high response, fast response and recovery rate, high selectivity and good stability, which are much better than NO 2 sensors based on pure rGO and rGO-SnO 2 hybrids. [ABSTRACT FROM AUTHOR]

Two heterocyclic-based energetic ionic salts were synthesized from 4-amino-3-hydrazino-5-mercapto-1, 2,4-triazole ( 1), which was used as proton bases reacting with nitric or perchloric acid. They were characterized by elemental analysis, IR spectroscopy, and single-crystal X-ray diffraction. In addition, their combustion heats were measured by oxygen bomb calorimetry and their heats of formation were predicted based on the combustion heats data. The non-isothermal kinetics parameters were calculated by Kissinger's method and Ozawa-Doyle's method, respectively. The critical temperature of thermal explosion and the thermodynamic parameters were also obtained by DSC results. The energetic properties and thermal analyses confirmed that the two salts maybe have potential application in the field of energetic materials. [ABSTRACT FROM AUTHOR]