DALTON TRANSACTIONS
·
2023
·Vol. 52
·期 14
·4389-4397
·
IF 4
Yujun Wu,Wei Shuang,Lin Yang,Chuanbao Cao
Graphene-based materials have been regarded recently as a promising substance for electrochemical energy conversion and storage devices owing to their unique structure and extraordinary properties. Herein, an enormously facile one-step pyrolysis approach is reported for the fabrication of ternary (P,S,N)-doped graphene, which is further investigated as an efficient metal-free electrocatalyst for the oxygen reduction reaction (ORR). Furthermore, optimized ternary-doped graphene can deliver excellent ORR catalytic activity that favors the four-electron ORR process and outstanding long-term durability (90.54% current retention after 20000 s which is far superior to that of commercial Pt/C) owing to the preferable synergetic coupling effect between P, S and N. Density functional theory (DFT) calculations were performed to reveal the synergetic coupling effect between doping elements in the ORR process. This work provides an extremely simple one-step pyrolysis method for the synthesis of P,S,N-doped graphene for electrochemical energy conversion and storage devices.
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高影响因子
FUEL
·
2023
·
IF 7.4
Haipeng Liu,Haifeng Jiang,Jiaxing Song,Ling Zhang,Yu Zhang,Yuhang Li,Wenpeng Hong
The production of high value-added liquid products by catalytic pyrolysis of cellulose has become an effective way to realize the efficient utilization of biomass. This work synthesized a series of Co-Ce, Co-Fe and Co-Mg composite metal catalysts and used them to obtain furans and ketones production. In addition, the CO 2 was used as a pyrolysis atmosphere to investigate the synergistic effect between CO 2 and the prepared catalyst. The results showed that the catalyst effectively promoted the depolymerization of cellulose and improved the oxygen transfer behavior between volatile matters during cellulose pyrolysis. As a reaction medium, CO 2 influenced the carbon distribution of products, thereby increasing syngas yield, and the CO 2 atmosphere promoted the formation of furans and ketones. Compared with those obtained by the non-catalytic pyrolysis in N 2 atmosphere, the relative contents of furans and ketones in the liquid products produced by the catalytic pyrolysis of cellulose in CO 2 atmosphere increased by about 13.38% and 9.8%. In the CO 2 environment, the generation ability for furans was Co-Mg catalyst > Co-Ce catalyst > Co-Fe catalyst, and the generation ability for ketones was Co-Ce catalyst > Co-Mg catalyst > Co-Fe catalyst. These works provide an important way for the efficient preparation of furans and ketones from biomass pyrolysis.
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PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES
·
2019
·
IF 3.176
Wen Cui,Xiaoli Kang,Xiaoying Zhang,Zhou Zheng,Xudong Cui
Recently, Metal-organic framework (MOF) has attracted general attention as self-sacrificial template to produce metal oxide semiconductor (MOS) for gas sensing. In this work, we fabricated a porous cubic microstructure of Co 3 O 4 through the facile pyrolysis of ZIF-67. The obtained Co 3 O 4 sustained a similar cubic morphology with ZIF-67 template, but much improved pore structure was achieved. Moreover, we attempted to modify the Co 3 O 4 with Au nanoparticles . Through a facile post-synthesis adsorption & pyrolysis, the Au nanoparticles with an average size of 15–20 nm were evenly dispersed on the surface of Co 3 O 4 . Then the obtained samples were investigated for acetone gas-sensing. Results showed that both Co 3 O 4 and its Au doped structure could be used for acetone detection, while due to the existence of metal-semiconductor heterojunction and the catalysis and spillover functions of Au nanoparticles, the prepared Au/Co 3 O 4 composite showed much improved acetone response and much shortened response-recovery time than that of the bare Co 3 O 4 structure.
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高影响因子
FUEL
·
2018
·
IF 4.908
Yang Zhou,Lu Li,Lijun Jin,Jian Zhou,Zhiwei Shi,Yang Li,Haoquan Hu
Coal pyrolysis is generally considered to initiate by cleavage of weak covalent bonds bridged between aromatic rings. The C–C covalent bonds are predominant bridged linkages among the framework of coal, which have a critical influence on coal pyrolysis reaction but lack of direct online observation. Five representative coal-related model compounds containing C–C bridged bonds, polypropylene (PP), polyvinylpyrrolidone (PVP), poly-4-vinylpyridine (P4VP), polystyrene (PS) and poly-4-vinylphenol, were selected to pyrolyze in an in-situ pyrolysis vacuum ultraviolet photoionization mass spectrometry (Py-VUV-PIMS). The soft ionized mass spectral detection can provide product distribution and evolved information of original products and intermediates, which are the key evidence to understand the initiation, recombination and reaction routes during pyrolysis process. Online analysis of pyrolysis reaction was found to be priority with cracking of C–C bond in the five polymer samples, and homologous free radicals and original products, which mainly include monomers, dimers and their alkyl and alkenyl radicals, were detected. The results reveal the cleavage temperature of C–C covalent bond is deeply related to its chemical environment, and obvious conjugation effect and steric effect for the bridged linkage were observed. In addition, the effect of hydrogen bond was also observed during the pyrolysis of model compounds containing hydroxyl groups, and intramolecular or intermolecular hydrogen bonding reduced the temperature at which C–C bridged bonds break. The analogous fracture mode and pyrolysis behavior of coal-related model compounds, which are beneficial to understand the reaction route and mechanism of coal pyrolysis, were discussed based on the experimental observations and theoretical calculation.
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高影响因子
ENERGY
·
2019
·
IF 5.537
Zixiang Gao,Ning Li,Siyuan Yin,Weiming Yi
Significant discrepancies of cellulose pyrolysis behavior in a micro-scale pyrolyzer and that in a large-scale reactor hinder the industrial application of those findings obtained from the former reactor. In this work, the pyrolysis behavior of cellulose in a fixed bed reactor was investigated, especially the residue evolution and the effects of temperature, material thickness and carrier gas flow rate on the products distribution and bio-oil composition. And a possible pathway for the cyclopentanones formation was proposed and competing reactions during cellulose pyrolysis with the consideration of heat and mass transfer effect were analyzed. It was found that high temperature promoted the cellulose decomposition and favored the cellulose to produce furfural, cyclopentanones and light linear compounds (such as acetic acid, hydroxy actaldehyde), and relative low temperature (<450 °C) and thicker material thickness (>2 mm) favored the dehydration of cellulose to yield levoglucosenone and furans compounds, and fast carrier gas flow rate declined the yield of most compounds but favored the recovery of levoglucosan. The findings of present study, to some extent, could provide guidance on process optimization of cellulose pyrolysis in a large-scale reactor to produce desired chemicals.
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高影响因子
BIORESOURCE TECHNOLOGY
·
2018
·
IF 5.807
Zihao Zhang,Hao Cheng,Hao Chen,Kequan Chen,Xiuyang Lu,Pingkai Ouyang,Jie Fu
Modified H-type ZSM-5 (HZSM-5) catalysts were prepared using hexadecyl trimethyl ammonium bromide (CTAB) as mesopore templates to enhance the activity for the catalytic fast pyrolysis of rice straw for aromatics compounds. A certain quantity of CTAB added into the HZSM-5 (HZ) forming hierarchical structure exhibited an improvement in the yield of the aromatics and a decrease in the yield of coke in comparison with that of bare HZ. In contrast, excessive CTAB addition resulted in a decrease in aromatic yield and an increase in coke yield. The effects of crystallinity, textural properties, morphological structure and acidity distribution on the production of aromatic compounds were measured by XRD, BET, TEM and NH 3 -TPD. The good crystallinity, small amount of mesopore formation and highest total acidity discovered in HZ-0.01 (the mole ratio of CTAB/SiO 2 is 0.01) provided the highest aromatic compound yield of 26.8% and the lowest coke yield of 39.2%.
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高影响因子
Journal of the Taiwan Institute of Chemical Engineers
·
2018
·
IF 3.849
Jian Rong,Hongli Chen,Fengxian Qiu,Tao Zhang,Yao Zhu,Dongya Yang,Jicheng Xu,Xinshan Rong,Qing Guo,Xiaoming Peng
In recent years, the pyrolysis of metal-organic frameworks (MOFs) has been widely employed to prepare advanced heterogeneous catalysts. However, large size or agglomeration caused by pyrolysis severely limits the performance of the catalysts due to the high mass transfer resistance. In this work, MOF crystals (Cu-BTC) in-situ grown on the biomorphic hierarchical layered double hydroxides (LDHs) surface (ZnAl-LDH/Cu-BTC) and it as a pyrolytic precursor to prepare layered double oxides/metal (ZnAl-LDO/Cu) composite catalyst were reported. ZnAl-LDH support induced the uniform distribution of nano-sized Cu-BTC on the nanosheets surface, and this unique method mediated Cu-BTC precursor for the in-situ construction of highly stable Cu nanoparticles under a high-temperature H 2 reduction. ZnAl-LDO/Cu exhibited excellent catalytic activity and stability for the reduction 4-nitrophenol (4-NP) in the presence of NaBH 4 , which could be recycled for fifteen successive cycles with a high reduction efficiency (over 93%). Meanwhile, the ZnAl-LDO/Cu demonstrated high catalytic efficiencies on rhodamine B, congo red, methyl orange and methylene blue dyes. Hence, the concept presented in this work can be further expanded to synthesis of other MOFs derived high-efficiency non-noble metal catalysts, which have a great potential as a cost-effective and environmentally-friendly reusable catalyst to replace noble metals catalyst in large scale catalytic application.
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JOURNAL OF POROUS MATERIALS
·
2017
·Vol. 25
·期 3
·845-853
·
IF 1.624
Wang Xiaoqin,Yang Yufei,Zhang Yong,Li Qiaoqin,Gong Ming,Zhang Runlan,Xiong Shanxin
N-doped porous carbon (NPC)/iron oxide (Fe x O y ) composites with rich nanoscale meso–macropores and high specific capacitances are successfully synthesized through a facile single-step pyrolysis approach, using coal-based polyaniline prepared through an in-situ polymerization method as a carbon and nitrogen source, and ferric citrate aqueous solution as a catalyst precursor. In NPC/Fe x O y , porous carbon mainly presents in the amorphous state. Nitrogen is successfully doped into NPC in the form of graphitic N, pyrrolic N, and pyridinic N. Fe x O y sphere particles with the diameter of 50–500 nm are embedded in the pores or on the surface of porous carbon. The NPC yield is about 65.4% and the nitrogen content is 0.122 wt%. The BET specific surface area and average pore width are 224.6 m 2 /g and 3.8 nm, respectively. NPC/Fe x O y composites demonstrate a high specific capacitance of 449 F/g at a current density of 1 A/g, good cycling stability, high capacitance retention of 88.2% at 5.0 A/g after 5000 cycles of charge and discharge, and good rate capability. Compared with NPC/Fe x O y from the pyrolysis of coal or polyaniline, NPC/Fe x O y from coal-based polyaniline possesses much better capacitance properties for owning a large number of evenly distributed and nanoscale meso–macropores greatly contributed by some interpenetrating network structures of coal-based polyaniline. This study will provide a facile and promising approach for the value-added applications of low-rank coal.
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CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Yuan Zeng,Yuanyuan Wang,Linyao Ke,Qiuhao Wu,Xiaojie Tian,Liangliang Fan,Kirk Cobb,Yuhuan Liu,Roger Ruan,Yunpu Wang
The pyrolysis of metal soaps to produce hydrocarbon rich fuel has been studied extensively. However, the combined effects of microwave radiation and metal ion types on hydrocarbon production have not been addressed. In this study, the microwave and conventional pyrolysis experiments were conducted on five metal soaps (Li soap, Na soap, K soap, Ca soap, Mg soap). The results demonstrated that the metal ions at the carboxyl end of the soap enhanced the polarity of the reactants, leading to a rapid increase in temperature under microwave conditions. With the ion radius increasing, the heating rate increased gradually. Compared with conventional pyrolysis, microwave pyrolysis exhibited a more rapid heating rate, a higher degree of carbon chain fracture, and a greater abundance of small olefin compounds, which promoted aromatization reaction and the release of CO, H 2 and CH 4 . In addition, the composition of the pyrolysis products derived from different metal soaps is affected by the characteristics of metal ions. As the radius of metal ions increased, the oxygen content in the liquid products decreased gradually, while the carbon content increased. The strengthening effect of microwave was further analyzed. With the increase in the radius of metal ions, the strengthening effect of microwaves on olefins formation was gradually weakened, while the inhibiting effect on alkanes formation was gradually enhanced. The structure of carboxylate network is affected by the radius of metal ions, which results in the regular change of the strengthening effect of microwave on olefins and other products. This study is highly significant in guiding the pyrolysis of soapstock waste to prepare olefins and alkanes with high efficiency and low energy consumption.
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高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Wenhui Li,Xiufang Shen,Zhonglin Chen,Tian Tian,Chenyong Liu,Cheng Gu,Weichuan Qiao,Ming Zhang
Ozone oxidation as a means of water treatment has received great attention in recent years, but ozone has low solubility and utilization, which hinders their efficient treatment of refractory pollutants. Herein, a dopamine-encapsulated 2D MOF strategy is proposed, where different metal salts including (acetylacetone iron, manganese, copper, etc.) are doped in it as active site precursors. After pyrolysis, 2D hollow porous carbon nanosheet catalysts such as Mn-HCNSs, Fe-HCNSs, Cu-HCNSs and Co-HCNSs are formed due to the rigid interface-induction of dopamine. Mn-doped Mn-HCNSs exhibits the best catalytic degradation performance when the antibiotic tetracycline is used as the target pollutant, and the degradation efficiency reached 90 % within 25 min (k = 0.213 min −1 ). This excellent catalytic performance can be attributed to several advantages: (i) the hollow porous 2D structure facilitates mass transfer and enhances the reaction kinetic constants; (ii) the confinement effect of dopamine wrapping facilitates the generation of more dispersed active sites and accelerates its ozone decomposition efficiency. This study expands the application of 2D MOF-derived porous carbon materials in ozone oxidation.
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CHEMISTRY-A EUROPEAN JOURNAL
·
2017
·Vol. 23
·期 40
·9517-9524
·
IF 5.317
Peiyuan Zeng,Jianwen Li,Ming Ye,Kaifeng Zhuo,Zhen Fang
Graphical Better batteries : Co 9 S 8 /N-C hollow spheres were successfully synthesized through synchronous pyrolysis and sulfurization of ZIF-67 (see figure). These structures deliver a distinguished performance when applied as the anode in lithium-ion batteries. Co 9 S 8 is considered a promising candidate as the anode material in lithium-ion batteries (LIBs) because of its remarkable electrical conductivity, high theoretical capacity, and low cost. However, the practical application of Co 9 S 8 is greatly restricted because of its poor cycling stability and rate performance, which result mainly from the large volume expansion and dissolution of the polysulfide intermediates during the charge/discharge process. In this report, Co 9 S 8 embedded in N-rich carbon hollow spheres are successfully designed and synthesized through an in situ pyrolysis and sulfurization process, employing the well-known ZIF-67 as the precursor and ethanethiol as the sulfur source. Co 9 S 8 nanoparticles embedded in the N-rich hollow carbon shell exhibit excellent lithium storage properties at a high charge/discharge rate. A discharge capacity of 784 mAh g −1 is obtained upon battery testing at a current density of 1 C (544 mA g −1 ). Even upon cycling at a current density of 4 C, the as-prepared Co 9 S 8 /N-C can still deliver a discharge capacity of 518 mAh g −1 . The excellent battery performance can be attributed to the hollow structure as well as the N-rich carbon encapsulation. Moreover, this metal–organic framework sulfurization route also shows good generality for the synthesis of other metal sulfide–carbon composites such as ZnS/N-C and Cu 2 S/C.
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高影响因子
ENERGY & FUELS
·
2015
·
IF 2.79
Haiyu Meng,Shuzhong Wang,Lin Chen,Zhiqiang Wu,Jun Zhao
Co-pyrolytic technology of plastic wastes and coal has been widely studied as a promising method to dispose of plastic wastes. Evaluation on pyrolytic behavior and product properties is important for optimizing this technology. In this work, pyrolytic behavior of poly(vinyl chloride) (PVC) blended with two typical coals from northern China (Pingzhuang lignite and Shenmu bituminous) was investigated by applying a nonisothermal thermogravimetric analyzer. Furthermore, scanning electron microscopy technique (SEM) was applied to explore the surface morphology of residual chars. Thermal analysis curves of PVC/coal blends showed nonadditivity performance meaning the existence of synergistic effects between PVC and coal during co-pyrolysis. Negative synergistic effects were observed in the temperature below about 370 °C, whereas positive synergistic effects happened at high temperature. In the final pyrolytic temperature, the formation of volatiles was promoted due to synergistic effects. In addition, isoconversional method was applied to calculate activation energy, and nonadditivity performance on the mean activation energies of PVC/coal blends was also found. The SEM results showed the fractal dimensions of the residual chars from pyrolysis of PVC/coal blends were larger than those from isolated samples, and increased with the increment of coal blending ratio. This variation trend showed that the inhomogeneous degree of the residual char from PVC increased by co-pyrolysis with coals, which can improve its reactivity of gasification or combustion.
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高影响因子
危险品化学品经营许可证（带存储）