ACS Omega
·
2025
·
IF 4.3
Haowen Tang,Shujun Zhou,Xiaoli Gu
Catalytic pyrolysis is a promising method for lignin degradation under anaerobic conditions. In this article, the effect of synthesized Co-based catalysts supported on acid-modified attapulgite catalysts on lignin pyrolysis was analyzed by thermogravimetric analysis, and its reaction mechanism function about lignin pyrolysis was investigated. It was shown that the pyrolysis processes of lignin alone and lignin catalytic pyrolysis were divided into three stages (early pyrolysis–midway pyrolysis–end pyrolysis), and the maximum weight loss peaks all showed a tendency to shift toward the high temperature as the heating rate increased due to the heat transfer limitation. The lowest activation energy of lignin catalytic pyrolysis was 44.7 kJ/mol, which was significantly lower than the conventional activation energy of lignin pyrolysis, indicating specific catalytic interactions between the catalyst active sites and the key functional groups in lignin. The results indicated that the addition of a catalyst could effectively improve the reaction rate of lignin pyrolysis.
研究领域:
能源化学
·
生物质热转化
·
催化
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
·
2016
·
IF 3.652
Yalun Hu,Isaac Nartey Oduro,Yong Huang,Yunming Fang
The structural characteristics and pyrolysis behaviors of two holocelluloses obtained from lignin-first biorefinery with Ru/C or Raney Ni as catalysts were studied in this paper. The infrared spectra of the remaining solid from the lignin-first biorefinery show that both lignin and a portion of hemicellulose were decomposed. Compared with Ru/C, Raney Ni was more effective for delignification and gave a holocellulose with higher degree of crystallinity, based on both the ratio of infrared bands (1372 cm −1 /2900 cm −1 ) and XRD analysis. The pyrolyses of holocelluloses were performed in fixed-bed and free-falling reactors, and the resulting char yields from both reactors were significantly higher than those of the parent biomass and commercial cellulose. This resulted from the cleavage of cellulose chain during the lignin-first biorefinery. Raney Ni related biorefinery cleaved cellulose chain to a higher degree.
研究领域:
生物化学
·
能源科学
·
材料科学
✓ 已验证
DOI
高影响因子
Progress in Natural Science-Materials International
·
2023
·
IF 4.7
Bianzheng You,Zhixing Wang,Ding Wang,Gui Luo,Duo Deng,Guochun Yan,Huajun Guo,Xinhai Li,Wenjie Peng,Mingxia Dong,Jiexi Wang
LiNiO 2 (LNO) is recognized as the most promising cathode material for next-generation lithium-ion batteries owing to its highest energy density and economic benefit in the layered oxide cathode materials systems. However, severe cation disordering, multiple phase transformations and poor lithium-ion diffusion kinetics , which result in rapid degradation of cycling stabilities and rate properties, hinder its further practical applications. Cobalt doping is an effective strategy to address such issues, but the influences of cobalt on LNO materials have not been figured out completely yet. Hence, a systematical investigation of cobalt doping for LiNiO 2 cathode materials prepared by spray pyrolysis is conducted. The addition of cobalt enhances the stabilities of layered structures and suppresses the cation disordering effectively. The multiple-phase transformations during cycling are also alleviated significantly. Furthermore, cobalt doping can decrease charge transfer resistances and improve lithium-ion diffusion kinetics, especially at high de-lithiation states. As a result, the electrochemical performances are improved comprehensively after cobalt doping. The LNO with optimal doping amount exhibits an improved capacity retention of 78.0% after 100 cycles as compared with 64.9% for pristine LNO, and an outstanding rate performance of 167.2 mA h g −1 with the current density of 5 C (1 C = 200 mA g −1 ).
研究领域:
材料科学
·
电化学
·
能源存储
·
无机化学
·
固态化学
✓ 已验证
DOI
高影响因子
CRYSTENGCOMM
·
2011
·Vol. 13
·期 11
·3905-3909
·
IF 4.006
Dongfei Sun,Xingbin Yan,Jiangtao Chen,Shengxue Yu,Litian Hu,Qunji Xue
In this paper, Zn2TiO4 and TiN nanofibers were prepared by a facile combination of electrospinning followed by thermolysis under different atmospheres. An N,N-dimethyl formamide (DMF)–ethanol solution of poly(vinylpyrrolidone) (PVP), Ti(IV)–isopropoxide (Ti(OC4H9)4) and zinc acetate (ZnAc) was used as the electrospinning precursor and the electrospun nanofibers were calcined at 600 °C in air to generate Zn2TiO4 nanofibers. Subsequently, a conversion from Zn2TiO4 nanofibers to TiN nanofibers was realized through a heat treatment at 1000 °C under an ammonia atmosphere. Investigations using field-emission scanning electron and transmission electron microscopes (FESEM and TEM) revealed the nano-scale fibrous morphology of the obtained products. Energy-dispersive spectroscopy (EDS) and X-ray diffraction (XRD) studies confirmed the chemical composition and crystalline structure of the Zn2TiO4 and TiN nanofibers, respectively. The electrochemical properties of the as-prepared TiN nanofibers indicated that the capacitance characteristic of the TiN phase was the electric double-layer capacitance. The value of the specific capacitance gradually decreased with the increase of discharge current density.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
Progress in Natural Science-Materials International
·
2018
·Vol. 28
·期 4
·529-533
·
IF 2.572
Zhenmin Ding,Yufei Ma,Dandan Peng,Lu Zhang,Yumeng Zhao,Yuan Li,Shumin Han
In this work, LiBH 4 –20 wt% PP composite was prepared by ball-milling with as-synthesized hierarchical pyrolysis polyaniline (PP) and LiBH 4 , and the hydrogen sorption performance as well as catalytic mechanism of the composite was studied. It is found that the onset desorption temperature of the composite decreases to 75 °C, almost 235 °C lower than that of the milled LiBH 4 . Moreover, the composite could release 4.1 wt% H 2 and rehydrogenate a total of 4.4 wt% H 2 when the temperature raiseds up to 400 °C, showing an outstanding reversibility, which even 3.9 wt% H 2 can be kept after five cycles. Through scanning electron microscopy (SEM) observation and X-ray diffraction (XRD) analysis, we found that the PP surface forms some nanoholes after hydrogenation-dehydrogenation cycles, which leads to the confinement of some LiBH 4 in the PP nanoporous structure, therefore, the hydrogen sorption kinetics and reversibility are significantly enhanced. In addition, we also found the oxygenic groups of the PP can react with LiBH 4 forming LiBO 2 and Li 3 BO 3 , where the containing Li–B–O bonds loaded in the porous structure of the PP catalyze the hydrogenation reaction of LiBH 4 .
研究领域:
材料科学
·
能源化学
·
纳米材料
·
固态储氢
·
催化化学
✓ 已验证
DOI
高影响因子
FUEL
·
2017
·
IF 4.601
Xiaoyan Jiang,Qiang Lu,Bin Hu,Ji Liu,Changqing Dong,Yongping Yang
Unimolecular decomposition mechanism is widely recognized as the major mechanism in lignin pyrolysis studies. In fact, during the real pyrolysis process, lignin and its derived intermediates, radicals and primary products are coexisting in the complex pyrolysis system. They may interact with each other, which will ultimately affect the whole pyrolysis process. However, current unimolecular decomposition mechanism does not take these interactions into consideration. In this study, density functional theory (DFT) methods and analytical pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) experiments are employed to explore the intermolecular interaction mechanism of lignin pyrolysis. The results indicate that strong interactions between radicals and lignin or its derived pyrolytic products will take place during the pyrolysis process through H-abstraction reactions. Therefore, intermolecular interaction mechanism, rather than unimolecular decomposition mechanism, should dominate the lignin pyrolysis process. These interactions can promote the primary and secondary decomposition reactions of lignin and its derived pyrolytic products, and simultaneously stabilize the radicals.
研究领域:
化学工程
·
能源科学
·
计算化学
✓ 已验证
产品关联
DOI
高影响因子
ENERGY & FUELS
·
2018
·
IF 3.024
Jun Hu,Shiliang Wu,Xiaoxiang Jiang,Rui Xiao
The structure–reactivity relationship in fast pyrolysis of lignin for monomeric phenolic compounds was studied on seven lignins from hardwood, softwood, and grass. The distribution of elements, functional groups, phenylpropane units, and interunit linkage bonds varied greatly across the lignins. Lignins from hardwood and grass prepared with mild conditions presented more C–O linkages. Pyrolysis–gas chromatography/mass spectrometry showed that the cleavage of unstable C–O linkages dominated the pyrolysis reaction at low temperatures, and the total yields of monomers peaked at 700 °C for most lignins. 4-Vinylphenol produced from acid extracted corn stalk lignin reached up to 4.77 wt % at 700 °C. Pyrolysis of grass lignins and woody lignins, which had more unstable C–O linkages, exhibited higher total yields of monomers. The pyrolysis behavior of lignin at low temperatures is closely related to its structural characteristics. Pyrolyzed at 500 °C, the total yields of monomeric aromatics were highly linearly correlated with the frequencies of C–O linkages (R2 = 0.86). This work demonstrates the significance of selecting the right lignin for producing monomeric aromatic compounds.
研究领域:
生物质能
·
化学工程
·
植物化学
✓ 已验证
产品关联
DOI
高影响因子
MATERIALS LETTERS
·
2020
·
IF 3.204
Yan Zhao,Minyue Wen,Chunhu He,Changlang Liu,Zongru Li,Yin Liu
The lignin residue produced by straw fermentation or straw acid hydrolysis is used as a carbon source to synthesize graphene. After adding tetrahydrofuran as a modifier and Fe(NO 3 ) 3 as a catalyst to lignin for pretreatment, the resulting product was heat treated at 900℃ for 3 h. The prepared graphene was characterized by XRD, Raman, HRTEM, and the electrochemical properties of the prepared graphene also were tested. The results of this study open up a new way for the efficient preparation of graphene based on renewable resources lignin. The prepared lignin-based graphene was used for electrochemical testing and found to be a good electrode material for super capacitors.
研究领域:
材料科学
·
可再生能源
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2020
·
IF 5.578
Yuhan Yang,Hongyun Hu,Fu Yang,Hua Tang,Huan Liu,Baojun Yi,Xian Li,Hong Yao
This study, for the first time, investigated the volatiles emission and thermochemical conversion mechanism of bio-waste during pyrolysis in molten salts (NaNO 3 -KNO 3 -NaNO 2 ) at 300 °C. Cations of molten salts acted as catalysts while anions participated in the pyrolysis reaction. Compared with salt-free pyrolysis, more bio-waste was decomposed in molten salts, to produce more than 14 times the mass of gaseous products and twice the mass of liquid products. Furthermore, the thermochemical conversion behavior of typical biomass constituents, i.e. cellulose, hemicellulose and lignin, was also distinguished. The results suggested that lignin was most easily pyrolyzed to form numerous liquid acids, some nitrated aromatic compounds and more CO, H 2 . In contrast, the decomposition of cellulose was certainly restricted while more significant effects of anions were found in hemicellulose cracking by generating nitrogen-containing heterocyclic rings and amines. Besides, interactions among different biomass constituents were confirmed to affect the generation of bio-waste pyrolysis products.
研究领域:
能源与环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2019
·
IF 5.128
Gongxin Dai,Yanan Zhu,Jiuzhong Yang,Yang Pan,Guanyu Wang,Prasert Reubroycharoen,Shurong Wang
The in-depth study of the cleavage behaviors of linkages in biomass is important for the better understanding of biomass pyrolysis mechanism . This study aimed to clarify the pyrolysis mechanism of the typical ether linkages in biomass including β-1,4-glycosidic bond, α-O-4 bond and methoxyl using cellobiose , benzylphenyl ether and guaiacol as the model compounds. Combining the detection of the key intermediates, especially radicals by SVUV-PIMS and the evaluation of the reaction pathways by density functional theory (DFT) quantum chemical calculations , it was found that the concerted cleavage of β-1,4-glycosidic bond was more kinetically favorable than homolytic cleavage and heterolytic cleavage, and the ring opening of cellobiose via the breakage of C1′-O was likely to occur before the cleavage of glycosidic bond . The α-O-4 bond in benzylphenyl ether was mainly cleaved by Cα-O homolysis, and it was easy for the formed radicals to recombine with each other to yield phenolic dimers. In the initial evolution process of methoxyl in guaiacol, homolytic demethylation was the most important unimolecular reaction , while demethoxylation and radical-induced rearrangement reactions were difficult to occur due to their high energy barriers. In the presence of the formed methyl radicals from homolytic demethylation reaction, these two reactions would occur since their energy barriers were significantly reduced at this condition.
研究领域:
化学工程
·
生物质能研究
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
·
2020
·
IF 3.905
Qingguo Zhou,Zhongyang Luo,Guoxiang Li,Simin Li
Lignin pyrolysis is a promising method for the sustainable production of phenolic compounds from biomass. However, detailed knowledge about the radicals involved in this process and their influence during the coking is missing. Herein, we report on the pyrolysis of guaiacol, a lignin monomer at 600 °C under inert and hydrogen gas conditions. During the pyrolysis process, the formed radicals were detected by two improved electron paramagnetic resonance spectroscopy methods. Successfully observed o-phenyl semiquinone radical anion, cyclopentadienyl radical, methyl radical, hydroxyl radical, methoxy radical, phenyl radical, phenoxy radical, etc. during the pyrolysis of guaiacol, as well as the changes of related radicals in different pyrolysis stages. It was found that o-semiquinone radical anions and cyclopentadienyl radicals were the key free radicals in the generation of coke and tar during the pyrolysis process. And through hydrogenation pyrolysis experiments, it was verified that the relative content of o-semiquinone radical and the solid coke were reduced with a hydrogen supply source. Our results showed that by controlling the key free radicals in the coking process, the formation of coke can be suppressed and the conversion efficiency can be improved.
研究领域:
化学工程
·
生物质能研究
✓ 已验证
产品关联
DOI
高影响因子
COMBUSTION AND FLAME
·
2019
·
IF 4.12
Dong-Xu Tian,Yue-Xi Liu,Bing-Yin Wang,Chuang-Chuang Cao,Zhong-Kai Liu,Yi-Tong Zhai,Yan Zhang,Jiu-Zhong Yang,Zhen-Yu Tian
Pyrolysis study of iso-propylbenzene (IPB) at 30 and 760 torr was carried out by using synchrotron photoionization and molecular beam mass spectrometry techniques. 0.5%IPB was diluted by helium and heated to 798–1148 K in a flow tube. Styrene was the most abundant aromatic intermediate at both pressures. Several polycyclic aromatics were only observed at 760 torr, such as 2-ethenyl-1, 4-dimethyl-benzene, fluorene, anthracene , phenanthrene, 2-methyl-anthracene and pyrene, while fulvene, 1, 3-cyclohexadiene, and 5-ethenylidene-1, 3-cyclopentadiene were only detected at 30 torr. A detail mechanism involving 306 species and 1990 reactions was developed by updating ipso-addition and unimolecular dissociation reactions of IPB as well as reactions related to styrene, indene and naphthalene . The mechanism could predict the pyrolysis of IPB and production of other intermediates well. Rate-of-production analysis shows that the formations of 2-phenethyl, 1-iso-phenylpropyl and 2-iso-phenylpropyl radicals are the main consumption reactions of IPB independent of pressure. Sensitivity analysis indicates that the unimolecular dissociation of IPB forming 2-phenethyl radical is the most significant promoting reaction at both pressures. H-abstraction reaction forming 1-iso-phenylpropyl radical tends to play a significant inhibiting effect on IPB consumption at 30 torr, while the most inhibiting reaction is self-combination of methyl radicals at 760 torr. Compared to n-propylbenzene experiments reported by Liu et al. (Combustion and Flame, 191 (2018) 53–65) and Yuan et al. (Combustion and Flame,186 (2017) 178–192.), IPB tends to produce larger quantities of benzene, styrene and indene under pyrolysis and oxidation conditions. These results will improve the understanding of the combustion and soot formation of IPB as a potential aviation surrogate fuel.
研究领域:
化学动力学
·
燃烧科学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）