Search

Catalytic doping plays an important role in enhancing the hydrogen storage performance of MgH2, while finding an efficient and reversible catalyst remains to be a great challenge in enhancing the de/rehydrogenation properties of MgH2. Herein, a bidirectional nano-TiH1.971 catalyst was prepared by a wet chemical ball milling method and its effect on hydrogen storage properties of MgH2 was studied. The results showed that all the TiH1.971 nanoparticles were effective in improving the de/rehydrogenation kinetics of MgH2. The MgH2 composites doped with TiH1.971 could desorb 6.5 wt % H2 in 8 min at 300 °C, while the pure MgH2 only released 0.3 wt % H2 in 8 min and 1.5 wt % H2 even in 50 min. It was found that the smaller the size of the TiH1.971 particles, the better was the catalytic effect in promoting the performance of MgH2. Besides, the catalyst concentration also played an important role and the 5 wt %-c-TiH1.971 modified system was found to have the best hydrogen storage performance. Interestingly, a significant hydrogen absorption amount of 4.60 wt % H2 was evidenced for the 5 wt %-c-TiH1.971 doped MgH2 within 10 min at 125 °C, while MgH2 absorbed only 4.11 wt% hydrogen within the same time at 250 °C. The XRD results demonstrated that the TiH1.971 remained stable in cycling and could serve as an active site for hydrogen transportation, which contributed to the significant improvement of the hydrogen storage properties of MgH2.

When coal is heated slowly (<10 °C/min), as in the Lurgi Fixed Bed Dry Bottom (FBDB) gasification process, products formed in the pyrolysis region of the gasifier include gas liquor, condensable tar, oil and non-condensable gases. Knowledge of the temperature profile together with the coal decomposition behaviour is of great importance when designing a fixed bed gasification plant, and although the characterisation of tar and the composition thereof has been reported extensively, there is limited literature available on the prediction of tar composition formed during slow pyrolysis. The focus of this study was to investigate temperature and coal rank effects on pyrolysis product yield, and to predict (using FLASHCHAIN ® ) the char, tar, water and gas yields when heated at slow heating rates for coals of different rank (ranging from lignite B to bituminous C). A modified Fischer Assay setup was used to investigate pyrolysis at temperatures higher than that of the ISO 647 standard, i.e. 520, 720 and 920 °C and the tar quality was determined via SEC–UV (size exclusion chromatography–ultraviolet), GC–MS (gas chromatography–mass spectrometry), SimDis (simulated distillation) and ultimate analysis. Only the char yield was found to be rank dependent and the average molecular weight of the coal derived tars (212–415 Da) compared well with previous studies. The rank dependence based on the composition of the evolved volatiles (tar and gas), showed a linear relationship with elemental oxygen and carbon contents of the derived tar, as well as for the oxygen containing gases (CO and CO 2 ). FLASHCHAIN ® was able to provide a relatively accurate prediction of the char yield, poorer predictions of the tar and water yields and no correlation with the gas yield. The simulated results on tar composition showed poor promise. Statistical regression was also applied in order to determine correlations between coal properties and the pyrolysis product yields and composition. It was found that the mineral elements (Na 2 O, MgO, CaO, TiO 2 and Fe 2 O 3 ) have strong correlations with tar yield, thus implying that catalytic effects of the mineral matter appear to play a significant role in the formation and decomposition of coal derived tar, which is a limitation in all pyrolysis predictive models. [ABSTRACT FROM AUTHOR]

Experiments were conducted to investigate the coal gasification performance and char characteristics affected by Ca/Na compounds. Firstly, the gasification reactivities of Ca-loaded coal, Na-loaded coal, and Ca/Na-loaded coal were compared by TGA in different gasifying agents including 100% H 2 O, 100% CO 2 , and 66.7% H 2 O + 33.3% CO 2 . Then, partially-gasified chars of Ca/Na-loaded coal with carbon conversion of 50% were prepared in different gasifying agents and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and nitrogen adsorption measurement. It was found that Ca together with Na showed a combined effect towards the gasification reactivity which was the most obvious in H 2 O/CO 2 mixtures, and Na could promote the synergistic effect caused by Ca catalysis at higher temperature (900 °C). Na can inhibit the agglomeration of CaO due to its excellent mobility and the formation of a eutectic mixture Na 2 Ca(CO 3 ) 2 . The marked improvement of CaO dispersion on the partially-gasified char in H 2 O/CO 2 mixtures results in the significant combined effect between Ca and Na and improves the synergistic effect at higher temperature. Moreover, the combined effect between Ca and Na during catalytic gasification can not only facilitate the gasification reactivity but also promote the development of pore structures for the gasified char. [ABSTRACT FROM AUTHOR]

In this paper, the effect of several transition metal salts such as FeCl2⋅4H2O, CoCl2⋅6H2O, NiCl2⋅6H2O and ZnCl2 on oil shale pyrolysis was investigated, based on thermal decomposition characteristics and product yields and compositions. The salts were added individually to Chinese Huadian oil shale by physical mixing. Pyrolysis experiments of oil shale with and without transition metal salts were performed in a thermogravimetric analyzer and a fixed bed reactor. Thermogravimetric analysis (TGA) suggested that CoCl2⋅6H2O and NiCl2⋅6H2O could promote oil shale pyrolysis, leading to a greater thermogravimetric mass loss than raw oil shale. By contrast, FeCl2⋅4H2O and ZnCl2 had only a slight effect on the decomposition behavior of oil shale. The results of fixed bed pyrolysis experiments showed that all metal salts enhanced the secondary cracking of shale oil, which decreased the oil yield and increased the pyrolytic gas yield. The metal salts could also catalyze the aromatization of aliphatic hydrocarbons to yield aromatic hydrocarbons. The catalytic activity of the studied salts decreased in the order NiCl2⋅6H2O > CoCl2⋅6H2O > ZnCl2 > FeCl2⋅4H2O. [ABSTRACT FROM AUTHOR]

A multi-responsive microgel having response to pH, temperature, and salt concentration was successfully prepared using a water-soluble monomer. Microgels were readily prepared from 2-( N-morpholino)ethyl methacrylate (MEMA) via emulsion polymerization using glycidyl methacrylate as a comonomer cross-linker. The morpholino groups of MEMA residues of microgels were able to give complexation with metal containing anions such as AuCl in acidic conditions. The reduction of aurate ions with sodium borohydride led to immobilized-gold nanoparticles (AuNP) in the microgel system. Average particle diameters of AuNPs were determined to be 10 ± 2 nm. The resulting AuNP-microgel system was examined as a nanoreactor for catalyst system and determined to be very effective in the reduction of 4-nitrophenol model reaction in aqueous media. AuNPs-microgel composite system had antibacterial properties against several Gram-positive and Gram-negative bacteria similar to amoxicillin. This P(MEMA- co-GMA) microgel is also very useful for different applications such as a host for metal nanoparticle production, a drug carrier or drug delivery system. [ABSTRACT FROM AUTHOR]

The behavior of co-pyrolysis and gasification of biomass and deoiled asphalt (DOA) was investigated. The co-pyrolysis of three biomasses and DOA reflected no obvious synergetic effect on the char yield, but the char's graphite degree reduced greatly. For the DOA was melted and stuck to the biomass surface during pyrolysis, the co-pyrolysis char showed an obvious agglomeration. The gasification rate of the co-pyrolysis chars was greatly increased by the addition of biomass, and the gasification curve were much similar to that of a homogenous char, indicating the blends were quite uniform and the alkali and alkaline earth metals in biomass could catalyze DOA gasification greatly. Sunflower stalk which has the highest potassium content and mineral content promoted the gasification rate best. Kinetic analysis showed that the average E values of the co-pyrolysis chars increased compared with the pure biomass char. The co-gasification of DOA and biomass is a good choice for disposing DOA. [ABSTRACT FROM AUTHOR]

The purpose of this work was to study the catalytic reaction and its mechanism of ammonium perchlorate (AP) with cobalt complex of 2,6-diamino-3,5-dinitropyrazine-1-oxide (Co-LLM-105) during thermal decomposition process. At first, the catalytic performance of Co-LLM-105 on the thermal decomposition of AP was investigated by TG-DSC, TG-FTIR, non-isothermal kinetic and α- T kinetic curves analyses. Secondly, the thermal decomposition mechanism of Co-LLM-105 in the absence and presence of AP was proposed based on TG, DTG, DSC and thermolysis/RSFTIR analyses. The results showed that Co-LLM-105 exhibited excellent catalytic activity on the thermal decomposition of AP. Meanwhile, AP also exhibited some catalytic effects on the thermal decomposition of Co-LLM-105. Both of the components had catalytic effects on each other during the process. The formation of active CoCO, CoO, CoO and Co(NH)(ClO) in situ in the system accounted for the higher catalytic activity of Co-LLM-105 for the thermal decomposition of AP was deduced. Graphical Abstract: Co-LLM-105 exhibited excellent catalytic activity on the thermal decomposition of AP. Meanwhile, AP also exhibited some catalytic effects on the thermal decomposition of Co-LLM-105. Both of the components had catalytic effects on each other during the process. [ABSTRACT FROM AUTHOR]

The catalytic effect of iron oxide on the oxidation kinetics of synthetic char was investigated in a fixed-bed reactor and in a conventional thermobalance for comparison. Synthetic char doped with iron oxide was obtained by pyrolyzing hydrochar at 800 °C, which had been synthesized by hydrothermal carbonization of cellulose in the presence of iron oxide. Isothermal char oxidation in the fixed-bed reactor resulted in the most reliable kinetic results. According to model-free kinetic analysis of these experiments at 15% conversion, iron oxide decreased the activation energy of char oxidation from 149 kJ/mol to 133 kJ/mol. Modeling of the conversion-time curves was first performed by using the uniform reaction model and then improved by using a n -th order power law. In the temperature range of 440–490 °C a very good agreement with the experimental data was achieved using n = 0.6. Activation energies amounting to 149 kJ/mol and 134 kJ/mol were derived for the undoped and iron oxide-doped char, respectively, well in line with the model-free analysis. [ABSTRACT FROM AUTHOR]

In the present study, changes in the sensing properties of SnO 2 on Carbon incorporation have been investigated in detail. The gas sensing response of size-selected SnO 2 and SnO 2 :C alloy nanoparticles prepared by gas phase deposition method have been investigated for H 2 and ethanol over a varied temperature range (50 °C–200 °C). The incorporation of carbon into SnO 2 lattice results in a large change in the sensing behaviour towards the two gases both having reducing nature. SnO 2 :C nanoparticles show positive sensing response for H 2 and negative sensing response for ethanol, whereas SnO 2 nanoparticles show a normal sensing response of an n-type semiconductor towards both the reducing gases. Observed values of activation energy of sensing and energy levels of O-vacancies observed in the PL spectra of SnO 2 and SnO 2 :C are consistent with these results. (i) Catalytic C–H interaction and (ii) modified work function of SnO 2 and C on hydrogenation resulting in alteration of electronic exchange between SnO 2 and C, and (iii) passivation effect of carbon during SnO 2 -ethanol interaction along with a possibility of reduction in SnO 2 sites in SnO 2 :C nanoparticles, are responsible for the observed behaviour. The present study shows that the incorporation of C in SnO 2 nanoparticles results in excellent selectivity towards H 2 and ethanol (both having reducing nature) in the low temperature range, normally not observed in oxide based resistive sensors. [ABSTRACT FROM AUTHOR]

Curing kinetics of two kinds of modified hyperbranched polyether/polyurethane interpenetrating polymer networks were investigated by in situ Fourier transform infrared spectroscopy. The results showed that the existence of stearate-terminated hyperbranched polyether (SHPE), without changing the reaction order between hydroxyl-terminated polybutadiene (HTPB) and isophorone diisocyanate (IPDI), still followed a second-order kinetic mechanism, but significantly enhanced its reaction rate; the activation energy was decrease from 28.3 to 16.6 kJ/mol. However, SHPE has no catalytic effect on the reaction between hydroxyl-terminated ethylene oxide tetrahydrofuran copolyether (PET) and IPDI. Main reason for this difference is that the inner and outer structures of SHPE were different. Their different repeating units bring different solubility parameters, resulting in hydroxyl in HTBP and IPDI enrichment near the inner structure of SHPE and HTPB backbone enriched outer layer of SHPE. However, the solubility parameter of PET was close to the inner structure of SHPE, so PET backbone was also in the vicinity of inner structure of SHPE, diluted -OH and IPDI concentration. The results suggested that by molecular structure design, it could gain catalyst for polyurethane. Graphical abstract: [ABSTRACT FROM AUTHOR]

The effects of (H 2 O) n ( n = 1–2) on hydrogen abstraction reaction (H 2 O 2 + HS → H 2 S + HO 2 ) have been investigated at the level of theories of B3LYP and CCSD(T). The aug-cc-pVTZ basis set has been used in the present treatment. The catalytic effect has been found to be small for water dimer and is significant for water, because the effective rate constant for the water-catalyzed reaction being 3–4 orders of magnitude larger than the corresponding water-dimer assisted reaction. Compared to the un-catalyzed reaction, the rate enhancement due to water catalysis at lower temperature (e.g., 240 K) was only 0.17%, which was increased to 72.7% at higher temperature (e.g., 325 K). [ABSTRACT FROM AUTHOR]

Platinum nanoparticles with diameters less than ∼5 nm were prepared on graphite particles by the coaxial arc plasma deposition, and the structure of platinum nanoparticles was investigated using high-resolution transmission electron microscopy. {110} facets of platinum nanoparticles parallel to the surface (0001) planes of graphite particles were most frequently observed. The platinum nanoparticles were found to be anisotropically deformed from the bulk face-centered cubic structure, and the lattice parameters of platinum nanoparticles were estimated by assuming monoclinic structures. No correlation was observed between the diameter and the lattice parameters of the platinum nanoparticles. Approximately two-thirds of the platinum nanoparticles were compressively strained, and the other platinum nanoparticles showed the expanded unit cells. The cube root of monoclinic unit cell of the platinum nanoparticles varied from a compression of 5.9% to an expansion of 2.8% as compared with the bulk lattice constant of platinum. [ABSTRACT FROM AUTHOR]

The objective of this study was to use Mg to improve the performance in chemical looping combustion. Oxygen carrier particles were synthesized in which Mg was doped into the M-sites with Fe, Co, Ni, and Cu to produce FeaMgbOx, CoaMgbOx, NiaMgbOx, and CuaMgbOx, respectively, with M/Mg ratios ranging from 1.5 to 3.0. The structure and properties of the prepared samples were characterized using XRD, SEM, CH 4 -/CO-TPD, XPS, and TGA. The XRD results explore that the Fe2Mg1Ox sample has a pure cubic structure of Fe 2 MgO 4 , whereas the Co2Mg1Ox and Ni2Mg1Ox samples exist as a solid solution. Nevertheless, the mixed compound formation of orthorhombic structure of Cu 2 MgO 3 and cubic structure of MgO has been observed in Cu2Mg1Ox. The CH 4 absorption is the highest on the Cu2Mg1Ox sample according to the CH 4 -TPD results. The CO-TPD and H 2 –TPR results showed that the adsorption of the Cu and Mg complex metal oxide is higher than that of the pure metal oxide. The oxygen carrier capacity of the samples was studied by isothermal H 2 (FR)/air (AR) and CH 4 (FR)/air (AR) redox cycle experiments at 850 °C using TGA. The promising results obtained from chemical looping combustion indicate that the CuaMgbOx samples are potentially useful for CLC in H 2 and CH 4 atmospheres. [ABSTRACT FROM AUTHOR]

The effect of the K 2 ZrF 6 catalyst on the hydrogen storage properties of the 4MgH 2 -LiAlH 4 composite was studied for the first time. The onset dehydrogenation temperature of the 4MgH 2 -LiAlH 4 -K 2 ZrF 6 composite was reduced to approximately 95 °C and 250 °C for the first two dehydrogenation stages; these values were lower by 40 °C and 25 °C compared with the undoped composite. Desorption kinetics measurement revealed that K 2 ZrF 6 -doped 4MgH 2 -LiAlH 4 released 3.0 wt% hydrogen in 20 min, whereas the undoped composite only released 2.0 wt% hydrogen within the same time. The activation energy for MgH 2 -relevant decomposition in the 4MgH 2 -LiAlH 4 composite was reduced from 129.8 kJ/mol to 102.9 kJ/mol after the addition of the K 2 ZrF 6 catalyst. The X-ray diffraction spectra displayed the formation of novel peaks of KH, Al 3 Zr and LiF after the de/rehydrogenation processes. These species functioned as active species and played a catalytic role in enhancing the dehydrogenation properties of the Mg-Li-Al composite. [ABSTRACT FROM AUTHOR]

This work aims to improve the catalytic activity of energetic Pb(II) complex of 2,6-diamino-3,5-dinitropyridine-1-oxide (Pb-ANPyO) on the thermal decomposition of ammonium perchlorate (AP). The Pb-ANPyO nanoparticles with a size of approximate 20 nm were successfully deposited on the surface of carbon nanotubes (CNTs) via chemical precipitation method, which exhibited a lower decomposition temperature than that of normal-sized Pb-ANPyO. The catalytic performance of Pb-ANPyO and Pb-ANPyO/CNTs nanocomposites on the thermal decomposition of AP were fully evaluated by thermogravimetry–differential scanning calorimetry TG-DSC, non-isothermal kinetics andα-Tkinetic curves measurements and analyses, respectively. The results showed that Pb-ANPyO/CNTs nanocomposites exhibited higher catalytic activities than that of Pb-ANPyO on the thermal decomposition of AP due to the synergistic effect of the CNTs and Pb-ANPyO nanoparticles. During the thermal decomposition process of AP catalyzed by Pb-ANPyO/CNTs nanocomposites, PbO/CNTs nanocomposites might be formed in situ and acted as the real catalyst with high catalytic activity, which promoted the thermal decomposition of AP. [ABSTRACT FROM AUTHOR]

ZnAlO and ZnMnO nanoparticles were synthesized by a modified co-precipitation method and characterized by means of Fourier transform infrared spectroscopy, X-ray diffraction, energy-dispersion X-ray spectrometer, and their morphology investigated by means of scanning electron microscopy. The effects of these nanoparticles on the thermal decomposition of ammonium perchlorate (AP) were examined by differential scanning calorimetery and thermogravimetery analyses. The results revealed that ZnAlO nanoparticles have little catalytic effect on this process, but ZnMnO nanoparticles have good catalytic effect on decreasing the decomposition temperature of AP and increasing the released heat. ZnAlO and ZnMnO nanoparticles increased the released heat of AP decomposition from 400 to about 736 and 1130 Jg, respectively, and AP decomposition temperature decreased from 420 to 400 and 358 °C in the same order. The higher catalytic activity of ZnMnO can be due to its p-type semiconductivity and the presence of some positive hole and defects. Also, the kinetic parameters such as pre-exponential factor and activation energy were calculated using Kissinger method. [ABSTRACT FROM AUTHOR]

The generation of problematic Ni-loaded waste from several applications alongside the high cost of the metal catalysts has caused the research effort to develop low cost Ni-catalysts. Therefore, the aim of this work is the study of the catalytic effect of nickel ions onto the thermal decomposition of the olive tree pruning (OTP) in nitrogen and oxygen-based atmospheres via thermogravimetric analysis. Experiments were carried out for the raw and Ni-OTP at three heating rates (5, 10 and 20 °C/min) and in three different reaction atmospheres (N 2 , 90% N 2 -10% O 2 and 80% N 2 -20% O 2 ). Results showed a slight displacement of the curves rightward in the first half of the curve for the Ni-OTP. Besides, the residual mass fraction was lower for Ni-OTP than for the raw one, changing the values from 24.59 to 15.94 for N 2 atmosphere, from 10.45 to 4.11 for atmosphere with 10% of O 2 and from 4.26 to 3.03 for atmosphere with 20% of O 2 . This behavior could be due to the inhibitory and catalyst effect that would be produced by the presence of nickel in the solid during the different stages of the thermal degradation. Besides, the environmental implication of presence of nickel during the thermal processes was analyzed and no negative environmental effect was observed. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Agro-Environment Science is the property of Journal of Agro-Environment Science Editorial Board and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The enhancing effect of calcium oxide (CaO) addition on steam gasification of four typical Chinese agricultural biomass wastes for H 2 production has been investigated in an atmospheric fluidized bed reactor under different conditions. The result indicates that CaO acts both a CO 2 absorbent and a catalyst in the gasification process. Its addition significantly increased the concentration and yield of H 2 and simultaneously decreased the content of CO and CO 2 in the product gas. At lower temperature (550–650 °C), the CO 2 absorption enhancing effect of CaO greatly promoted the gasification process to produce a product gas with high content of H 2 and low CO and CO 2 . While at higher temperature (700–800 °C), the catalytic effect of CaO became significant, the cracking of pyrolytic volatiles and steam gasification of volatiles and char as well as WGS reaction were intensified, which also caused the increase in H 2 yield in spite of the decrease in H 2 concentration. The increases of molar ratio of CaO–C (CaO/C, 0–2) and mass ratio of steam to biomass (S/B, 0.8–2) were both beneficial for H 2 production process. CaO addition showed limited effect on CH 4 and C 2+ even at high temperature and high mass ratio of steam to biomass. The type of biomasses is closely associated with H 2 yield, which is closely related to the volatile and C content of biomass materials. [ABSTRACT FROM AUTHOR]

Petcoke, as a byproduct of petroleum refinery process, can be used as feedstock of gasifiers due to its high carbon content and high calorific value. However, its low gasification reactivity and low ash content restrict its application to some gasifiers. In this work, experimental study on co-gasification reactivity of petcoke with coal under CO 2 atmosphere was investigated in a drop-in-fixed-bed reactor in the temperature range of 1200–1400 °C. Produced CO was monitored continually using an online mass spectrometry to calculate the carbon conversion and gasification rate. The experimental results reveal that the gasification reactivity of petcoke can be improved greatly by co-gasifying with coals or by loading their ashes, even at temperatures higher than the ash fusion temperature. Both the coal and its ash can improve the gasification reactivity of petcoke. The synergistic effect is closely related to the composition of minerals in coal but not coal rank. The high content of active components such as Ca- and Fe- in coal or ash is beneficial for co-gasification. Some coals, however, are lack of these active components and with high Si- and Al-components content which may retard the gasification reaction. During co-gasification, the oldhamite (CaS), anhydrite (CaSO 4 ) and magnetite (Fe 3 O 4 ) have positive catalytic effect, while mulite (3Al 2 O 3 ·2SiO 2 ) has negative effect on gasification reaction at high temperature. [ABSTRACT FROM AUTHOR]

The Mg - 9.3 wt% (TiH 1.971 -TiH)−0.7 wt% Nb nanocomposite has been synthesized by hydrogen plasma-metal reaction (HPMR) approach to enhance the hydrogen sorption kinetics of Mg at moderate temperatures by providing nanosizing effect of increasing H “diffusion channels” and adding transition metallic catalysts. The Mg nanoparticles (NPs) were in hexagonal shape range from 50 to 350 nm and the average size of the NPs was 177 nm. The small spherical TiH 1.971 , TiH and Nb NPs of about 25 nm uniformly decorated on the surface of the big Mg NPs. The Mg - TiH 1.971 -TiH-Nb nanocomposite could quickly absorb 5.6 wt% H 2 within 5 min at 573 K and 4.5 wt% H 2 within 5 min at 523 K, whereas the pure Mg prepared by HPMR could only absorb 4 and 1.5 wt% H 2 at the same temperatures. TiH 1.971 , TiH and Nb NPs transformed into TiH 2 and NbH during hydrogenation and recovered after dehydrogenation process. The apparent activation energies of the nanocomposite for hydrogenation and dehydrogenation were 45.0 and 50.7 kJ mol −1 , which are much smaller than those of pure Mg NPs, 123.8 and 127.7 kJ mol −1 . The improved sorption kinetics of the Mg-based nanocomposite at moderate temperatures and the small activation energy can be interpreted by the nanostructure of Mg and the synergic catalytic effects of Ti hydrides and Nb NPs. [ABSTRACT FROM AUTHOR]

NaMgH3 perovskite hydride and NaMgH3-carbon nanomaterials (NH-CM) composites were prepared via the reactive ball-milling method. To investigate the catalytic effect of CM on the dehydriding kinetic properties of NaMgH3 hydride, multiwall carbon nanotubes (MWCNTs) and graphene oxide (GO) were used as catalytic additives. It was found that dehydriding temperatures and activation energies (ΔE1 and ΔE2) for two dehydrogenation steps of NaMgH3 hydride can be greatly reduced with a 5 wt. % CM addition. The NH-2.5M-2.5G composite presents better dehydriding kinetics, a lower dehydriding temperature, and a higher hydrogen-desorbed amount (3.64 wt. %, 638 K). DE1 and DE2 can be reduced by about 67 kJ/mol and 30 kJ/mol, respectively. The results suggest that the combination of MWCNTs and GO is a better catalyst as compared to MWCNTs or GO alone. [ABSTRACT FROM AUTHOR]

It is obvious that boron nitride (BN) can provide excellent barrier to heat and flame due to its large lamellar structure and high thermal stability. Here, we combined the barrier effect of BN with the catalytic effect of transition metal ions to obtain a novel nanocomposite coating. Specifically, polyethyleneimine (PEI) molecules were loaded on the BN surface by Lewis acid-base action. Then, the phytic acid (PA) molecules were self-assembled on the PEI surface by electrostatic action. Finally, copper ions (Cu2+) were complexed in the PA molecules to obtain BN/PPA@Cu hybrids. The fire performance and smoke suppression effects of BN/PPA@Cu loaded epoxy resin (EP) composite coatings were discussed and analyzed by large plate experiments, thermal weight loss analysis, etc. In comparison, the backside temperature of the steel plate with BN/PPA@Cu/EP composite coating was stabilized at 167.8 °C, which was significantly lower than other samples, while its lowest smoke density rating (39.9) confirmed its excellent smoke suppression effect. The results of thermal weight loss analysis proved that BN/PPA@Cu/EP had the lowest T max (334.8 °C), which was a direct response to the catalytic effect of transition metal ions. Additionally, the highest char residue (31.1%) and the maximum expansion height (21.9 mm) of BN/PPA@Cu/EP conferred high fire resistance and smoke suppression to the composite coating. These findings are a good reference for obtaining high performance fireproof coatings. [Display omitted] • PA, Cu2+ were loaded on BN/PEI surface sequentially by electrostatic interaction and complexation. • The synergistic effect of PEI, PA and Cu2+ effectively improved the fire performance of the coating. • Residual CuO and BN improved the strength and thermal insulation of the char layer. [ABSTRACT FROM AUTHOR]

• Role of AAEM in catalyzing pyrolysis reactions in N 2 and CO 2. • Minerals catalyze solid, liquid, and gaseous pyrolysis products. • Mineral doping, heating rate, temperature, and atmosphere all influenced the pyrolysis products. • Minerals catalytically affected the decomposition of the levoglucosan fraction in the tars. • CO 2 inhibited (700 °C) or enhanced (1027 °C) the formation of polycyclic aromatic hydrocarbon. This paper investigates the changes in reactivity and physicochemical characteristics of char and tar produced from severe heat treatment in either inert or CO 2 -rich atmospheres of a synthetic fuel doped with Fe&Mg and K&Mg sulfates. The mineral-free model fuel was obtained by hydrothermal carbonization (HTC) of cellulose. The comparison of Py-GC/MS-GC/TCD, heated strip reactor (HSR), and drop tube reactor (DTR) results highlighted that mineral doping, heating rate, temperature, residence time and atmosphere all interacted and influenced the pyrolysis products. Fe&Mg increased the light permanent gases during flash pyrolysis. The minerals catalytically affected the decomposition of the levoglucosan fraction in the tars. In N 2 , the addition of K&Mg influenced the oxy-aliphatic tars, while Fe&Mg had a stronger impact on oxy-aromatic compounds. Depending on the pyrolysis temperature and residence time (and reactor type), CO 2 inhibited (700 °C in the HSR) or enhanced (1027 °C in the DTR) the formation of polycyclic aromatic hydrocarbon (PAHs) in the tars. Chars doped with Fe&Mg always exhibited higher reactivity than the chars doped with K&Mg. While the presence of CO 2 during pyrolysis favored the aromatization of the chars especially in combination with doped minerals, alkali mineral interaction with CO 2 decisively altered char reactivity. [ABSTRACT FROM AUTHOR]

Reduced graphene oxide-gold nanoparticles nanocomposites (rGO-AuNPs) with high surface-enhanced Raman scattering (SERS) activity was created by biomass-assisted green synthesis with Lilium casa blanca petals biomass for the first time, and its application for methylene blue (MB) degradation was explored through in-situ monitoring. Lilium casa blanca petals biomass was used as a reducing agent to reduce GO and chloroauric acid successively when carrying out rGO-AuNPs in-situ synthesis while it also acted as a capping agent. The produced rGO had oxygen-containing functional groups which had an outstanding performance in enhancing the SERS effect. Characterization results confirmed that the AuNPs were grafted onto the rGO sheet, and the mechanism study showed that total flavonoids in Lilium casa blanca petals biomass were the main biological compounds involved in the reduction. rGO-AuNPs had a high Raman enhancement factor (EF) which could reach 3.88 × 107. The synthesized nanocomposite also had a good catalytic activity that could be employed as catalyst in MB degradation, and it could complete degradation within 15min. The reaction rate increased linearly with the amount of rGO-AuNPs, and the degradation could be in-situ monitored both by UV and SERS. [Display omitted] • rGO-AuNPs were synthesized by biomass-assisted green synthesis method. • Lilium casa blanca petals were used both as reducing and capping agents. • Synthesized rGO-AuNPs had high SERS activity with an EF of 3.88 × 107. • rGO-AuNPs showed good catalytic activity for methylene blue degradation monitoring. [ABSTRACT FROM AUTHOR]

In this study, roasted spent HDS ash (sHDSc-A) was used for the first time to catalytically pyrolyze oily spent HDS catalysts (sHDSc) to improve the yield and quality of pyrolysis oil. The results showed that sHDSc-A promoted the decomposition of coke in oily sHDSc, resulting in the recovery of more oil and gas. Meanwhile, sHDSc-A significantly improved the quality of the pyrolysis oil. They inhibited the aromatization of alkanes to increase the saturation of the pyrolysis oil from 59.39% to 74.25% and the H/C radio from 1.62 to 1.72; promoted the decomposition of long-chain alkanes to increase the content of C11–C22 from 41.97% to 61.99%; enhanced the conversion of carboxylic acids to ketones led to the reduction of heteroatomic compounds such as N (56.10%–45.39%), S (66.95%–56.59%), and O (45.26%–26.70%) in the pyrolysis oil. The promotion of sHDSc-A in the pyrolysis process is attributed to the catalytic effect of the metal oxides in sHDSc-A. Among them, Al 2 O 3 and Fe 2 O 3 can promote decarboxylation of carboxylic acids and reduce O mobility, while MoO 3 and Fe 2 O 3 play a significant role in reducing coke and increasing pyrolysis oil. NiO can also promote methane vapor reforming, and thus increase the production of H 2 in non-condensable gas. This study achieves self-circulation of oily sHDSc with a "waste-treatment-waste" strategy that presents the advantage of value-added energy recovery and waste reuse. [Display omitted] • The roasted HDS catalyst ash (sHDSc-A) can be recirculated as a pyrolysis catalyst. • The sHDSc-A enhance the yield and quality of pyrolysis oil. • SHDSc-A gives the oil lower heavy hydrocarbons and fewer heteroatomic compounds. • The MoO 3 , Fe 2 O 3 , NiO and Al 2 O 3 in sHDSc-A play different catalytic roles. • The possible catalytic pyrolysis mechanism of oily sHDSc-A was presented. [ABSTRACT FROM AUTHOR]

The interphase formed between solid polymer electrolyte (SPE) and highly reductive lithium metal largely determines the overall performance of the battery. Although various types of nanoparticles have been continuously employed as fillers to achieve a stable interphase for long cycling performance, the irregular growth of lithium dendrites cannot be completely suppressed due to uneven lithium deposition. Herein, a new type of zwitter-ion modified metal-organic framework (NH 3 +·SO 3 -@ZIFs) is prepared as a modifier for PEO-LiTFSI. Due to the unique ionic structure of NH 3 +·SO 3 -@ZIFs, the formed electrostatic interaction could inhibit the movement of TFSI-, enhance the ion migration number. More importantly, TOF-SIMS effectively confirms the formation of Li+-conductive LiF-rich SEI due to the catalytic effect of NH 3 +·SO 3 -@ZIFs, which could homogenize the lithium flux, inhibit the growth of Li dendrite. Results show that the PEO-NH 3 +·SO 3 -@ZIFs exhibits high ion migration number (t Li+ = 0.78). The Li/Li symmetric cells equipped NH 3 +·SO 3 -@ZIFs SPE can be stably operated for more than 4600 h at 60 °C while the full cell with LiFePO 4 cathode also enables long-term stability over 1200 cycles with capacity stabilizing at around 103 mAh g−1, demonstrating the great potential of this kind of SPEs for preparing high-performance LMBs. [Display omitted] • The work clarifies the importance of valence bond synergism in inhibiting Li dendrite growth. • The PEO-NH 3 +·SO 3 -@ZIFs exhibits high t Li+ of 0.78 and excellent Li plating/stripping performance of 4600 h at 0.1 mA/cm2. • The PEO-NH 3 +·SO3-@ZIFs exhibits long-term stability over 1200 cycles with discharge capacity of 103 mAh g−1 retained. [ABSTRACT FROM AUTHOR]

The effects of discharge power, voltage/Current, initial concentration, pH, and air flow rate on the oxidative degradation of hydroquinone were investigated, respectively, by a wire–cylinder dielectric barrier discharge reactor under a NaCl concentration of 10 g/L. Results indicated that the removal efficiency of hydroquinone increased from 74.6 to 88.2% when the discharge power increased from 30 to 50 W. Moreover, an enhancement from 68.5 to 85.6% was observed when the air flow rate changed from 20 to 40 L/h, at 10-min reaction time and an initial hydroquinone concentration of 40 mg/L. The observed maximum pseudo-first-order kinetic constant was about 0.3820 ± 0.0409 min−1under a discharge power of 60 W and air flow rate of 80 L/h. Compared with other factors, discharge power, pH, and air flow rate played a significant role in improving the oxidation rates of hydroquinone. This work provides new insights into our understanding of plasma-induced degradation of hydroquinone under a NaCl concentration of 10 g/L. [ABSTRACT FROM AUTHOR]