Nano Research
·
2022
·Vol. 16
·期 5
·6067-6075
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IF 10.269
Ding Jieting,Guo Danyu,Hu Anqian,Yang Xianfeng,Shen Kui,Chen Liyu,Li Yingwei
The preparation of supported high-density metal nanoparticles (NPs) is of great importance to boost the performance in heterogeneous catalysis. Thermal transformation of metal-organic frameworks (MOFs) has been demonstrated as a promising route for the synthesis of supported metal NPs with high metal loadings, but it is challenge to achieve uniform metal dispersion. Here we report a strategy of “spatial isolation and dopant anchoring” to resist metal aggregation in the pyrolysis of MOFs through converting a bulk MOF into dual-heteroatom-containing flower-like MOF sheets (B/N-MOF-S). This approach can spatially isolate metal ions and increase the number of anchoring sites, thus efficiently building physical and/or chemical barriers to cooperatively prevent metal NPs from aggregation in the high-temperature transformation process. After thermolysis at 1,000 °C, the B/N-MOFS affords B,N co-doped carbon-supported Co NPs (Co/BNC) with uniform dispersion and a high Co loading of 37.3 wt.%, while untreated bulk MOFs yield much larger sizes and uneven distribution of Co NPs. The as-obtained Co/BNC exhibits excellent electrocatalytic activities in both hydrogen evolution and hydrazine oxidation reactions, and only a voltage of 0.617 V at a high current density of 100 mA·cm −2 is required when applied to a two-electrode overall hydrazine splitting electrolyzer.
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Crystals
·
2022
·Vol. 12
·期 7
·948
·
IF 2.67
Haolong Zhai,Xiaoping Cui,Yuping Gan
Taking the combustion tear gas mixture as the research object, the system formula was optimized by adding a different mass fraction of 5-amino-1H-tetrazole(5AT). TG-DSC, a thermocouple, and a laser smoke test system were used to characterize the characteristic combustion parameters such as combustion temperature and velocity, as well as the end-point effects such as smoke concentration and particle size. Starink’s method, the Flynn–Wall–Ozawa method, and the Coats–Redfern method were used to evaluate the pyrolysis kinetic parameters of the samples. The results show that when the mass fraction of 5-amino-1H-tetrazole in the system is 10%, the maximum combustion temperature of the sample decreases by nearly 70 °C and the smoke concentration increases by 12.81%. The kinetic study also found that with a different mass fraction of 5-amino-1H-tetrazole in the system, the main reaction model of the mixed agent in the first, third, and fourth stages of pyrolysis changed significantly, but for the second stage of sample pyrolysis, the main reaction model (the A4 model) showed a high degree of consistency, which can be considered as the thermal diffusion stage of the tear agent capsicum oleoresin (OC) (the temperature range is 220~350 °C), which is highly consistent with the results of the TG-DSC analysis. It was also confirmed that OC’s thermal diffusion is mainly concentrated in this stage. The results of this study show that adding an appropriate amount of the combustible agent 5-amino-1H-tetrazole to the combustion tear gas mixture can improve its combustion performance and smoking performance, which provides an important, new idea for the development of a new generation of safe, efficient, and environmentally friendly tear gas mixtures.Keywords:5-amino-1H-tetrazole;tear gas mixture;combustible agent;combustion pyrolysis characteristics;dynamics research
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ENERGY & FUELS
·
2022
·
IF 4.654
Yang Li,Bin Hu,Hao Fu,Yu-long Wu,Zhen-xi Zhang,Ji Liu,Bing Zhang,Qiang Lu
Cellulose can be selectively converted into levoglucosenone (LGO), a high-value anhydrosugar, through fast pyrolysis with acidic catalysts. Herein, phosphorus molybdenum tin mixed metal oxides (P-Mo/SnO2) were prepared for the selective production of LGO from the in situ catalytic fast pyrolysis (CFP) of cellulose, where the PO43–, P-support, and Mo6+ species in P-Mo/SnO2 played the determining role in promoting depolymerization, dehydration, and deoxygenation reactions. Pyrolysis-chromatography/mass spectrometry (Py-GC/MS) tests were carried out to explore the influence of catalyst-to-cellulose (CA-to-CL) ratio, phosphomolybdic acid (PMA) loading, and pyrolytic reaction temperature on LGO preparation. The results demonstrated the maximal LGO yield could reach 17.98 wt % via using P-Mo/SnO2 with the PMA loading of 50 wt % at the pyrolysis temperature of 300 °C and the CA-to-CL ratio of 1:1. Moreover, the highest LGO yield could be up to 12.70 wt % in lab-scale CFP tests at 300 °C and the CA-to-CL ratio of 2:1, and the LGO yield could remain above 10 wt % after five runs of catalyst calcination regeneration.
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ENERGY CONVERSION AND MANAGEMENT
·
2022
·
IF 11.533
Donghua Xu,Junhao Lin,Shichang Sun,Rui Ma,Mingliang Wang,Jinlong Yang,Juan Luo
Microwave pyrolysis of nitrogen-rich biomass for bio-oil is a green and sustainable pathway to realize energy conversion and produce high-value nitrogenous chemicals. This work selected three typical amino acids (serine (Ser), glutamic acid (Glu), and phenylalanine (Phe)) as nitrogenous model compounds for biomass, and the distribution characteristics and formation mechanisms of the nitrogenous chemicals in bio-oil were studied in depth. Results showed that the amino acid structure and pyrolysis temperature were the crucial factors affecting the distribution and selectivity of nitrogenous chemicals. The nitrogenous chemicals were mainly produced at 200–500 °C from the model amino acids, and the nitrogen in Ser was more prone to accumulating in bio-oil compared with Glu and Phe. At 300 °C, the model amino acids generated numerous amines and cyclic amides through decarboxylation, decarbonylation, and dehydration. Higher temperatures (400 and 500 °C) promoted amines/amides to form nitriles and N-heterocycles, with the releasing of H 2 . Nitriles (including propionitrile and phenylacetonitrile) were typically produced by the straight-chain dehydrogenation of amines. Ser, Glu, and Phe produced N-heterocycles (including pyrazine, pyrrole, 2-pyrrolidone, and indole) based on the cyclization and dehydration between carbonyl and amino compounds, intramolecular dehydration, and cyclization dehydrogenation of phenethylamine, respectively. Finally, the possible formation pathways of the main nitrogenous chemicals were proposed, and the kinetics and thermodynamic analyses were performed through density functional theory (DFT) calculations. The findings could provide theoretical support for the nitrogenous chemicals production from microwave pyrolysis of amino acids and biomass.
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JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
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2022
·
IF 6.437
Wen-tao Li,Dong-hong Nan,Guan Zhang,Kai Li,Yan-qin Huang,Qiang Lu,Li-juan Gao,Wan-zhao Huang,Xiao-feng Han,Shan-wei Ma
The N-doped activated carbon (NAC) was prepared for bagasse (BAG) pyrolysis with 9,10-dihydroanthracene (DHA) to selectively improve production of individual 4-ethyl phenol (4-EP). Both pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) and lab-scale apparatus were employed to conduct catalytic fast pyrolysis (CFP) experiments. The effects of N-doping modification, pyrolysis temperature, DHA/BAG ratio and NAC/BAG ratio on yield and selectivity of 4-EP were comprehensively investigated. Results indicated that the NAC exhibited excellent catalytic abilities in improving 4-EP production. About 3.03 wt % of 4-EP was obtained over NAC in the absence of DHA, whereas the 4-EP yield over activated carbon was only 2.46 wt %, indicating an increment of 23.17 % via N-doping modification. The 4-EP yield reached the maximum of 4.75 wt % with a selectivity of 25.12 % at temperature of 350 °C with a DHA/BAG ratio of 7:20 and NAC/BAG ratio of 3:1, indicating 88.45 % of 4-VP (5.37 wt %) was converted into 4-EP. Result of lab-scale tests showed that 4-EP production attained the highest value (4.02 wt %) with a selectivity of 25.53 % at temperature of 350 °C with DHA/BAG and NAC/BAG ratios of 1:5 and 1.5:1, respectively. Finally, the possible mechanism on 4-EP formation from BAG pyrolysis with co-assist of NAC and DHA was inferred.
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MICROCHEMICAL JOURNAL
·
2022
·
IF 5.304
Yilin Wang,Chenxi Wang,Li Zhang,Jiaodi Li,Rongjie Li,Qian Fu,Chunyan Li,Pengcheng Zhao,Yixi Xie,Junjie Fei
Kaempferol (KA), an important polyphenolic compound, is able to combat a variety of inflammatory diseases. Here, a ZnWO 4 / porous nanocarbon based electrochemical sensor has been constructed to detect KA for the first time. Innovatively, ZnWO 4 has been synthesized by pyrolysis using ZIF-8 as a zinc source, while porous nanocarbon was introduced. The nanocomposites have been characterized by X-ray diffraction, X-ray photoelectron spectroscopy and scanning electron microscopy and demonstrated that Acidified ZnWO 4 /porous nanocarbon has been successfully prepared. Notably, the excellent catalytic properties of ZnWO 4 and the great enrichment ability and conductivity of porous nanocarbon greatly enhanced the detection performance of the sensor for KA with a linear range of 0.009–0.7 μM and a LOD of 2.03 nM. In addition, the sensor has obtained satisfactory results for the detection of KA in actual natural samples (broccoli and kaempferia powder). The reaction sites and redox mechanism of KA were shown by density functional theory. Finally, the sensor is highly sensitive and stable, making it a novel detection method with extremely high potential applications.
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JOURNAL OF ENVIRONMENTAL MANAGEMENT
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2022
·
IF 8.91
Liang Chen,Yafei Shen
Waste cathode (BC) from spent lithium-ion battery (LIB) was preliminarily studied for the catalytic pyrolysis of chitin biomass using thermogravimetric and pyrolysis-gas chromatography/mass spectrometry analysis. Compared with the dry-mixing method (BC1), the wet-impregnation method (BC2) significantly increased the decomposition rate of chitin pyrolysis and decreased the apparent activation energy from 85 kJ/mol to 76 kJ/mol. BC2 had a superior catalytic effect on the conversion of heavy components into light fractions. In particular, the selectivities for acetamides and acetonitrile were improved. Furthermore, BC2 enhanced the cleavage of glucosidic, C–O, and C–C bonds, thereby improving the thermolysis of chitin to acetamido acetaldehyde. The production of acetamides, acetonitriles, and other light components (e.g., ketones) was further enhanced via deoxygenation and hydrogenation reactions. Additionally, the selectivity of N-heterocycles (pyridine and pyrrole) and their derivatives (tar-N surrogates) decreased, indicating that tar was significantly reduced during the catalytic pyrolysis and gasification of chitin biomass.
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PubMed
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
·
2022
·
IF 5.876
Kongyan Yang,Feng Zhou,Huixia Ma,Chuntao Liu,Fangwei Ma,Guang Wu
A series of nanocrystalline ZSM-5 zeolites with abundant intercrystalline mesopores was fabricated by a hydrothermal crystallization method without any mesopore template. The ZSM-5 zeolite was characterized by XRD , XRF , N 2 adsorption, NMR, SEM, TEM and NH 3 -TPD and used for the catalytic fast pyrolysis (CFP) of cellulose . The external surface area of the nanocrystalline ZSM-5 zeolite reached 146.6 m 2 /g, larger than the external surface area of conventional ZSM-5 (57.9 m 2 /g). The product yields of the CFP reaction were studied over different Si/Al ratios of nanocrystalline ZSM-5, and the aromatic yield of nanocrystalline ZSM-5 was generally higher than the aromatic yield of conventional ZSM-5. The relationship between the surface area, acid amounts and product yields was established by drawing a linear fitting curve. The results show that both pore structure and acidity have important effects on aromatic yield and coke yield. Aromatics are generated in micropores, and the increase in external surface area caused by reducing the particle size improves the pyrolysis of cellulose to generate bio-oil vapours, which further diffuse into micropores to generate aromatics.
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Catalysis Science & Technology
·
2022
·Vol. 12
·期 5
·1586-1597
·
IF 6.177
Shuai Wang,Nan Jiang,Tianhan Zhu,Qiang Zhang,Chunlei Zhang,Huan Wang,Yanguang Chen,Feng Li,Hua Song
Hydrodeoxygenation (HDO) of phenolic compounds is a promising technology to convert biomass materials to value-added chemicals and fuels. However, the development of highly efficient catalysts remains a great challenge. In this work, a facile one-step pyrolysis–phosphidation strategy for the synthesis of carbon-encapsulated nanostructured Ni2P@C(x) catalysts (x is the initial mass ratio of NaH2PO2 to Ni-MOF-74) under a N2 atmosphere from a metal–organic framework (Ni-MOF-74) was proposed and the prepared catalysts were used for HDO of phenol. The effects of different values of x and reaction conditions on the phenol HDO performance as well as product distribution were investigated. The results showed that as compared to the Ni@C catalyst (4.2%), the de-oxygenated product selectivity was enhanced 22.8 times by the introduction of the P species due to the promoted dehydration of cyclohexanol over Ni2P@C(x) catalysts. Ni2P@C(3) exhibited the best catalytic performance at the temperature of 250 °C, pressure of 2 MPa, and reaction time of 2 h; the conversion of phenol was 100%, and the total yield of deoxygenated products reached 100%. The HDO of phenol over the Ni2P@C(x) catalyst mainly proceeded via the HYD pathway (hydrogenation of the aromatic ring to cyclohexanol, and dehydration of cyclohexanol to give rise to cyclohexene followed by hydrogenation to cyclohexane).
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ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2023
·Vol. 30
·期 28
·72966-72977
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IF 5.8
Wang Zhongmiao,Yang Kun,Lin Daohui
Biochar releases colloidal particles into the environment during applications and aging which can become carriers of pollutants and influence on the environmental risk of pollutants due to the excellent adsorption and migration properties of biochar colloids (BCCs). The adsorption and desorption behaviors of BCCs can be different from their bulk ones due to the colloidal size, which merits specific studies. Herein, the adsorption and desorption of 2,4,4′-trichlorobiphenyl (PCB28) as a representative on BCCs released from bulk biochars prepared from bamboo chips at 300, 500, and 700 C and the effects of solution properties were specifically investigated. Results show that the adsorption was dominated by pore filling and π–π interaction, and thus, BCCs prepared at higher temperature with greater pore volume and aromaticity had higher adsorption of PCB28. Results show that the adsorption was dominated by pore filling and π–π interaction, and thus, BCCs prepared at higher temperature with greater pore volume and aromaticity had higher adsorption of PCB28. The saturation adsorption amounts of PCB28 on BCC300, BCC500, and BCC700 were 21.9, 40.3, and 62.4 mg/g, respectively. It is noteworthy that PCB28 possessed a significant desorption hysteresis from BCCs, with the hysteresis index (Ce = 80 μg/L) increased from 0.380 to 0.661 as the preparation temperature of BCCs rising from 300 to 700 ℃. High concentration of NaCl (100 mmol/L) was unfavorable for the adsorption and desorption. The presence of humic acid or fulvic acid (FA), especially the smaller FA, could inhibit the adsorption and desorption of PCB28 on BCCs due to micropore blocking. In seawater, groundwater, surface water, and soil solution samples, the PCB28 adsorption of BCCs was inhibited to varying degrees in comparison with that in deionized water, and the desorption was noticeably inhibited in the groundwater sample. These findings provide valuable information for the understanding of interactions between BCCs and organic contaminants in natural waters and for the environmental application of biochars as well. Graphical abstract
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高影响因子
INDUSTRIAL CROPS AND PRODUCTS
·
2023
·
IF 5.9
Danni Li,Rui Shan,Jing Gu,Xianhai Zeng,Lu Lin,Taoli Huhe,Haoran Yuan,Yong Chen
In this study, the co-pyrolysis behavior, products, and the migration of heavy metals (HMs) during the co-pyrolysis of textile dyeing sludge (DS) and litchi shells (LS) were investigated. Thermogravimetric (TG) analysis was used to identify the pyrolysis stages of mixtures, and the activation energy ( Ea ) of the main pyrolysis stages was calculated by Kissinger Akahira Sunose (KAS) method. The average of Ea decreased from 326.1 to 232.5 kJ/mol with increasing the proportion of LS. The bio-oil compositions indicated that the interaction effect between DS and LS mainly promoted the generation of phenols and acid compounds and inhibited the production of nitrogenated compounds, ketones, and ethers. The emission characteristics of gases from the co-pyrolysis of three samples were analyzed by TG-FTIR. The results found that the addition of LS could inhibit the generation of NO x precursors. Finally, LS in co-pyrolysis was beneficial to the increase of Cu, Zn, Cr, and Ni stable fractions (F3 +F4) to 96%, 69%, 99% and 80%, and the potential Ecological Risk Index (RI) of biochar was reduced to 7.26. This study provided a cleaner and more efficient idea for co-pyrolysis strategy and resource utilization of solid waste .
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高影响因子
INDUSTRIAL CROPS AND PRODUCTS
·
2023
·
IF 5.9
Dongmei Bi,Mengqian Yin,Fupeng Huang,Jiawen Zhang,Weiming Yi
To clarify the evolution mechanism of environmentally-persistent free radicals (EPFRs) in biochar as a function of pyrolysis temperature, three-component pyrolytic carbon was characterized by electron paramagnetic resonance (EPR) spectroscopy. Four types of EPFRs were distinguished by using the peak splitting method. The EPFRs in three-component pyrolytic carbon obtained at a pyrolysis temperature of 300 °C were mainly oxygen-containing free radicals (57.31–83.63 %). Upon increasing the pyrolysis temperature, simple aromatic ring radicals were formed by the dehydrogenation of biomass, and then the polymeric aromatic radicals formed, accompanied by π-electron delocalization to form phenyl-π radicals. Biomass pyrolysis was simulated by mechanically mixing the three components in different proportions. A comparison of the experimental and theoretical values indicated that interactions between the three components did not obviously affect the EPFR concentration in the range of 450–550 °C, with a maximum relative error of 12.78 %. A prediction model for the EPFRs concentration in multi-component pyrolytic carbon was proposed. This study also clarified the generation and transformation mechanisms of EPFRs in three-component pyrolytic carbon, thus providing guidance for generating and regulating biochar EPFRs.
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