ACS Catalysis
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2018
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IF 11.384
Huifang Liu,Hongji Li,Jianmin Lu,Shu Zeng,Min Wang,Nengchao Luo,Shutao Xu,Feng Wang
Photocatalysis is a potentially promising approach to harvest aromatic compounds from lignin. However, the development of an active and selective solid photocatalyst is still challenging for lignin transformation under ambient conditions. We herein report a mild photocatalytic oxidative strategy for C–C bond cleavage of lignin β-O-4 and β-1 linkages using a mesoporous graphitic carbon nitride catalyst. Identifications by solid-state NMR techniques and density functional theory (DFT) calculations indicate that π–π stacking interactions are most likely present between the flexible carbon nitride surface and lignin model molecule. Besides, low charge recombination efficiency and high specific surface area (206.5 m2 g–1) of the catalyst also contribute to its high catalytic activity. Mechanistic investigations reveal that photogenerated holes, as the main active species, trigger the oxidation and C–C bond cleavage of lignin models. This study sheds light on the interaction between complex lignin structures and the catalyst surface and provides a new strategy of photocatalytic cleavage of lignin models with heterogeneous photocatalysts.
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高影响因子
FUEL
·
2018
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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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Asian Journal of Organic Chemistry
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2018
·Vol. 7
·期 10
·2039-2044
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IF 2.496
Qian-Qian Huang,Wei-Qiang Yu,Xiao-Lin Luo,Jin Gao,Jie Xu
Graphical An alternative method for glycerol hydrogenolysis to CH 4 and ethylene glycol that proceeds through preferential C−C bonds cleavage catalyzed by highly-dispersed Ru catalysts with tunable particle sizes via carbothermal reduction has been reported. An alternative method for the conversion of crude glycerol was proposed to produce renewable energy methane and high-value chemical ethylene glycol through preferential cleavage of C−C bonds, catalyzed by highly dispersed Ru-based catalysts prepared by carbothermal reduction. It was found that the Ru particles size could be tuned by adjusting the reduction temperature, and the size firstly decreased then increased with raising of the temperature of carbothermal reduction. This resulted in the opposite tendency of catalytic performance against the Ru particle sizes in hydrogenolysis of glycerol, in which the glycerol conversion and yield of C−C bond cleavage increased firstly and then decreased. Ru catalysts carbothermal reduced at 450 °C possessed highly dispersed Ru nanoparticles with uniform particle sizes about 1.0 nm that showed high hydrogenation activity and selectivity of C−C bond cleavage as well as good stability that could be recycled in aqueous phase hydrogenolysis of glycerol.
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APPLIED CATALYSIS A-GENERAL
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2015
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IF 3.942
Qunfeng Zhang,Wei Xu,Xiaonian Li,Dahao Jiang,Yizhi Xiang,Jianguo Wang,Jie Cen,Stephen Romano,Jun Ni
The preparation of supported palladium sulfides catalysts has attracted much attention due to their good sulfur-resistant properties in the hydrogenation of sulfur-containing compounds. In this work, we unambiguously demonstrated that Pd/C catalyst could be in situ sulfided by organic sulfur-containing reactant molecules and the sulfidation was highly dependent on temperature. The in situ sulfidation of Pd/C catalyst was composed of a reaction of Pd with the sulfur derived from the cleavage of C S bond of sulfur-containing reactant molecules, followed by a transformation to Pd x S y at high temperatures (around 120 °C). The sulfided Pd/C catalyst could be used for at least 18 recycles without a significant loss in its activity during the hydrogenation of sulfur-containing nitrobenzene at 180 °C with 3 MPa H 2 , which could be attributed to the stable presence of Pd 4 S and Pd 16 S 7 .
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Scientific Reports
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2017
·Vol. 7
·期 1
·1-10
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IF 4.259
Feng Shanglei,Yang Yingguo,Li Li,Zhang Dongsheng,Yang Xinmei,Xia Huihao,Yan Long,Tsang Derek K. L.,Huai Ping,Zhou Xingtai
An in-situ real-time synchrotron-based grazing incidence X-ray diffraction was systematically used to investigate the crystal structural evolution of carbon fiber reinforced carbon matrix (C/C) composite impregnated with FLiNaK molten salt during the heat-treatment process. It was found that the crystallographic thermal expansion and contraction rate of interlayer spacing d
002 in C/C composite with FLiNaK salt impregnation is smaller than that in the virgin sample, indicating the suppression on interlayer spacing from FLiNaK salt impregnated. Meanwhile the crystallite size L
C002 of C/C composite with FLiNaK salt impregnation is larger than the virgin one after whole heat treatment process, indicating that FLiNaK salt impregnation could facilitate the crystallization of C/C composite after heat treatment process. This improved crystallization in C/C composite with FLiNaK salt impregnation suggests the synthetic action of the salt squeeze effect on crooked carbon layer and the release of internal residual stress after heating-cooling process. Thus, the present study not only contribute to reveal the interaction mechanism between C/C composite and FLiNaK salt in high temperature environment, but also promote the design of safer and more reliable C/C composite materials for the next generation molten salt reactor.
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PubMed
高影响因子
JOURNAL OF POWER SOURCES
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2016
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IF 6.333
Jian Xie,Liang Tong,Liwei Su,Yawei Xu,Lianbang Wang,Yuanhao Wang
Yolk-shell Si@void@C nanostructure has greatly improved the low Li + /electron conductivity and buffered the huge volume variation of Si, whereas the surface corrosion and passivation of the Si yolks in electrolytes still limit the lithium storage capability. Herein, core-shell yolk-shell Si@C@void@C nanohybrids were proposed and successfully prepared for the first time. Compared with Si@void@C, the newly-proposed structure introduced core-shell Si@C nanoparticles as the yolks instead. Such extra carbon shell can not only decrease the electrical resistance between Si yolks and hollow carbon shells but also effectively protect Si yolks from electrolyte corrosion, i.e. , the formation of Li 2 SiF 6 layers on Si surface confirmed by X-ray diffraction and transmission electron microscopy . As a result, the Si@C@void@C electrodes exhibited remarkably enhanced reversible capacity, cycling stability (∼1366 mA h g −1 after 50 cycles at 500 mA g −1 , with a capacity retention of ∼71% with respect to the initial reversible capacity of 1910 mAh g −1 at 100 mA g −1 ), and rate performance (with a capacity retention of ∼60% at 4000 mA g −1 ). This work shows the paramount role of the inner carbon shell of Si@C@void@C in limiting the electrolyte corrosion and probably improving the electronic conductivity .
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CHEMICAL ENGINEERING JOURNAL
·
2025
·
IF 13.2
Chen Cheng,Changyong Zhao,Shuiping Cai,Yingkang Tian,Rongjin Lin,Dan Luo,Xiaofei Yang,Xuejie Gao,Runcang Sun
Inhomogeneous lithium deposition and dendrite growth severely restrict the achievable energy density of both solid-state and liquid lithium metal batteries (LMBs). While the application of functional separator materials can effectively mitigate these issues, existing research predominantly focuses on either liquid or solid-state batteries, with limited dual application in both systems. Herein, in this work, an Al 2 O 3 @bacterial cellulose (Al 2 O 3 @BC) separator is proposed to realize the dual application from liquid to a wide-temperature range of solid-state LMBs. X-ray Photoelectron Spectroscopy (XPS) and High-Resolution Transmission Electron Microscope (HRTEM) analyses revealed that the an in-situ formed Li-Al-O protective layer on the lithium metal surface facilitated the uniform diffusion and nucleation of lithium ions (Li + ). Consequently, both liquid and polyethylene oxide (PEO)-based solid-state lithium-symmetric batteries assembled with Al 2 O 3 @BC can operate for over 2000 h at a current density/ capacity of 0.1 mA cm −2 / 0.1 mAh cm −2 . The NCM523 full cell with Al 2 O 3 @BC delivers 150.3 mAh g −1 at 0.2C after 120 cycles. More importantly, the ionic conductivity (4.63 × 10 −4 S cm −1 ) in solid-state batteries is also significantly promoted, and the LFP full cells demonstrating stable cycling across a broad temperature range of − 20 °C to 60 °C.
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INDUSTRIAL CROPS AND PRODUCTS
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2024
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IF 5.6
Zhen Huang,Penghao Sun,He Liu,Chunyu Ren,Xiangyu Lin,Minggui Shen,Zhaoshuang Li,Xu Xu
To obtain high-valued aromatic products, it is paramount to cleave the C α −C β bonds in lignin under mild conditions selectively. Nevertheless, this task remains daunting due to the formidable dissociation energies and steric hindrance associated with these bonds. Herein, a facile, efficient and cost-effective strategy for selectively breaking the C α −C β bond in lignin with visible-light irradiation and room temperature is proposed, facilitated by the utilization of the ferric-doped mesoporous graphitic carbon nitride (Fe/mpg-CN) photocatalyst. Collective contributed by the reduced band gap and photoluminescence, combined with intensified visible-light absorption and enhanced photocurrent, the effectiveness in photocatalytic activity of Fe/mpg-CN is offered. Specifically, a high conversion rate (98 %) of the lignin model compound (2-phenoxy-1-phenylethanol), coupled with an excellent selectivity of 98 % in cleaving the C α −C β bonds is achieved by Fe/mpg-CN. Photogenerated holes are indicated as the main active species through comprehensive mechanistic investigations. Additionally, the successful photocatalytic depolymerization of the complex dimer model compound (conversion rate ∼ 96 %) and pine kraft lignin further corroborate the satisfying photocatalytic activity and selectivity of Fe/mpg-CN. This study introduces a promising and viable strategy for the selective breaking of lignin through photocatalysis, offering significant implications for the sustainable production of valuable aromatic compounds.
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ACS Catalysis
·
2024
·
IF 11.3
Weijie Geng,Di Zhang,Ni Zhen,Jianxin Du,Jing Dong,Chengpeng Liu,Shi-Lu Chen,Yingnan Chi,Changwen Hu
The electrochemical coupling of biomass platform molecules to biofuels provides a promising method for addressing energy crises and environmental issues. However, achieving high yields of C–C coupling products under ambient conditions remains a challenge. Herein, we present a highly efficient electrocatalyst, [Cu(pz)]3[PW12O40] (Cu-PW12), fabricated by combining a Cu-pz complex (pz = pyrazine), a redox catalytic center, with Keggin-type PW12O40, and an electron sponge. Cu-PW12 exhibits remarkable catalytic activity for the electroreductive C–C coupling of furfural (FF), a bulk and low-cost biomass platform chemical, to produce a jet fuel precursor, hydrofuroin (HDF). Under neutral and ambient conditions, over 99% of FF is converted and the selectivity of HDF reaches 91.2%. Furthermore, experimental and theoretical studies, including control experiments, kinetic isotope studies, electrochemical and spectral analyses, and DFT calculations, reveal a synergistic catalysis effect between Cu center and PW12. The introduction of PW12 not only facilitates electron transfer, improving FF conversion, but also changes the rate-determining step, favoring the formation of HDF. Under turnover conditions, the Cu-PW12 catalyst is initially reduced and then FF is reduced by the Cu center to ketyl radical after protonation on the electrode surface. Finally, the self-coupling of two ketyl radicals in solution leads to the generation of HDF.
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Journal of Energy Chemistry
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2024
·
IF 14
Hongqiang Yang,Jianfeng Zheng,Guoyu Wang,Yifei Gao,Yatao Yang,Jia Li,Xiaojin Han,Yan Cui,Zhanggen Huang
Photoelectrocatalytic coupling CO 2 and volatile organic compounds (VOCs) is a promising green strategy for the synergistic conversion of the two carbon-containing resources to C 2 products. The catalytic efficiency is always at the mercy of chemical inertness of CO 2 and the competitive hydrogen evolution of H 2 O. Herein, a modified g-C 3 N 4 /ZnAl-LDH Z-scheme heterojunction catalyst with dual reaction site was rationally designed and precisely constructed. The Faraday efficiency of ethanol reached 68.67% with a corresponding formation rate of 227.3 μmol g −1 h −1 . As revealed by in-situ characterizations and density functional theory calculations, CO 2 and HCHO were absorbed at Zn site and N site, respectively. Then, *CO generated from CO 2 and HCHO was converted to *CH 3 O and *CHO on the dual-active-site heterojunction. The detailed reaction mechanism experiments indicated that C–C coupling only occurred between *CO and *CH 3 O in electrocatalysis process. Apart from the “*CO + *CH 3 O” path, another “*CO + *CHO” coupling path was also detected in photoelectrocatalytic process. The selectivity of ethanol was significantly enhanced due to the synthesis of dual-site catalyst and the dual-path coupling path between CO 2 and HCHO simultaneously driven by light and electricity.
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Journal of Energy Chemistry
·
2024
·
IF 14
Xiaoyue Zhang,Yong Yang,Yingjie Hu,Lijun Xiong,Tianyu Wang,Panjie Li,Jinyou Shen
Photothermal catalytic CO 2 conversion provides an effective solution targeting carbon neutrality by synergistic utilization of photon and heat. However, the C–C coupling initiated by photothermal catalysis is still a big challenge. Herein, a three-dimensional (3D) hierarchical W 18 O 49 /WTe 2 hollow nanosphere is constructed through in-situ embodying of oxygen vacancy and tellurium on the scaffold of WO 3 . The light absorption towards near-infrared spectral region and CO 2 adsorption are enhanced by the formation of half-metal WTe 2 and the unique hierarchical hollow architecture. Combining with the generation of oxygen vacancy with strengthened CO 2 capture, the photothermal effect on the samples can be sufficiently exploited for activating the CO 2 molecules. In particular, the close contact between W 18 O 49 and WTe 2 largely promotes the photoinduced charge separation and mass transfer, and thus the *CHO intermediate formation and fixedness are facilitated. As a result, the C–C coupling can be evoked between tungsten and tellurium atoms on WTe 2 . The ethylene production by optimized W 18 O 49 /WTe 2 reaches 147.6 μmol g − 1 with the selectivity of 80%. The in-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and density functional theory (DFT) calculations are performed to unveil the presence and significance of aldehyde intermediate groups in C–C coupling. The half-metallic WTe 2 cocatalyst proposes a new approach for efficient CO 2 conversion with solar energy, and may especially create a new platform for the generation of multi-carbon products.
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Chem Catalysis
·
2023
·
IF 9.4
Xiuzheng Zhuang,Jianguo Liu,Yangqi Ji,Xiaojun Wu,Xinghua Zhang,Lungang Chen,Qi Zhang,Longlong Ma
Summary Pharmaceutical synthesis keeps close ties with the development of heterogeneous catalysts ; in this work, we report a facile way to prepare cobalt nanoparticles encapsulated by a graphene-shelled matrix, whose catalytic activity for a wide range of primary amines is proved to be broadly effective. As determined by its structural features, such a graphene-shelled matrix is characterized by surface defects such that inner metallic atoms are individually pulled outside by the divacancy sites; as a result, the delivery of metallic sites facilitates the easy substitution of the –NH 2 moiety toward functionalized and structurally diverse molecules by directly activating the C=O or C–N bonds in varied substrates, providing cost-effective access to numerous amines and other precursors for more complex drug products. In addition, the performance of this catalyst in a continuous test can reach at least 180 h without any loss of efficiency, which can be mainly ascribed to the protection of graphene-shelled structures.
研究领域:
药物化学
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催化
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材料科学
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