ACS Catalysis
·
2021
·
IF 13.084
Yuebing Xu,Wenda Yu,Hao Zhang,Jian Xin,Xiaohui He,Bing Liu,Feng Jiang,Xiaohao Liu
Various Co-based SAPO-34 catalysts were prepared using different methods, including ion exchange (IE), incipient-wetness impregnation (IWI), and solid-phase grinding (SPG), to correlate the chemical states of Co species with the C–H and C–C bond scissions in ethane dehydrogenation. The IE-prepared Co/SAPO-34 led to stable, unreducible, and isolated exchanged Co sites anchored on the zeolite framework with a structure of −AlF–O–Co–O– and showed the highest selectivity to ethylene of close to 98% at 600 °C, which suggests that these Co sites favors suppressing the C–C bond scission in ethane. In comparison, the IWI- and SPG-prepared Co/SAPO-34 catalysts, especially for those with a high Co loading, inevitably give Co oxide clusters that are easily reduced into metallic Co. Together with catalytic results, characterizations, and DFT calculations, it is confirmed that the reduced Co clusters, especially for those outside SAPO-34 channels without the confinement effect, favor both C–H and C–C bond scission, boosting the conversion of ethane into CH4 or/and coke; however, the ionic-state −Co–O– species can smoothly terminate the ethane dehydrogenation for the ethylene product due to relatively high energy barriers for both C–H and C–C bond scission, avoiding a deep dehydrogenation and C–C cracking. As expected, the unreducible −Co–O– sites are very stable in the title reaction without deanchoring from the zeolite framework in a 100 h cyclic test. This study not only demonstrates the stable −Mδ+–Oδ− structure favorable for suppressing C–C bond scission but also highlights a catalyst-constructing strategy for Co-based and similar metal-based catalysts for dehydrogenation of other light alkanes.
研究领域:
催化化学
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材料科学
·
计算化学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2023
·
IF 7.4
Bo Wang,Wenrui Yan,Xianlong Gong,Quan Zhu
Coking during the endothermic hydrocarbon fuel pyrolysis is a key issue that needs to be solved in the development of regenerative cooling technology for high-speed aircrafts. The compounds containing hydroxyl groups are developed to inhibit coking by regulating coking pathway during the thermal cracking of hydrocarbon fuels. Pyrolytic deposition experiments of n -decane with additives were performed using the method of electrical heating. The anti-coking performance of the additives was characterized by means of gas chromatograph–mass spectrometer (GC–MS), scanning electron microscopy (SEM), temperature programmed oxidation (TPO) and Raman spectroscopy. The results showed that the degree of cracking is reduced at low fuel temperature due to the dilution of the additives, and the additives do not affect the fuel cracking as the fuel temperature increased. With the function of additives, the masses of filamentous and amorphous coke were decreased. A possible mechanism for the additives inhibiting coking has been proposed. The additives containing hydroxyl groups can block the initial coking reaction path to inhibit coking at the source. In general, the hydroxyl radicals released by the additives oxidize the coking precursors to prevent its further growth, and react with the substrate to form particulate matters serving as passivation coating, inhibiting the bulk phase coking and metal catalytic coking simultaneously. This work provides significant ideas for inhibiting coking by regulating coking reaction pathways.
研究领域:
化学工程
·
航空航天材料科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Zhiyang Zhao,Dongqiang Cai,Juan Liu,Guifu Zou,Qiang Zhang,Zhanlong Song,Cuiping Wang,Longzhi Li
Direct cracking of hydrogen sulfide (H 2 S) can be used to obtain high purity hydrogen (H 2 ), thus avoiding the waste of hydrogen resources by the traditional Krauss process. Microwave-induced discharge of spherical graphitization petroleum coke (PC) was proposed to solve the problem of low efficiency and high energy consumption of H 2 S cracking. The PC was prepared by microwave-assisted desulfurization and metal (Fe, Co) catalytic graphitization to obtain better discharge effect. Subsequently, the graphitized PC was applied to induce microwave discharge, and the effects of graphitization parameters on the discharge performance were discussed. Lastly, the attention was concentrated on multi-effects catalytic decoupling and cracking kinetic properties of microwave-induced discharge for H 2 S cracking. PC with Fe 1 /Co 2 loading exhibited greater graphitization degree ( I D / I G = 1.027) (30.7 % than petroleum coke), brought stronger discharge intensity (initial and ending intensity at 4.08 V and 2.73 V in one-hour), and better discharge stability (67 % after one-hour) compared to PC raw coke. H 2 S cracking through microwave discharge catalysis exhibited a favorable catalytic effect, obtained a complete conversion at the initial stage and remained 95.58 % after one-hour, with H 2 yield of 98.1 %. With Fe 1 /Co 2 loading, H 2 S cracking had the least activated energy, 14.96 kJ/mol, which was the multi-effects of microwave discharge catalysis, thermal-catalysis and Co-catalysis. It was further calculated that discharge-catalysis dominated in H 2 S cracking, with the highest contribution, followed by Co-catalysis, and thermal-catalysis had the lowest contribution.
研究领域:
化学工程
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能源科学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
CHINESE JOURNAL OF CATALYSIS
·
2013
·
IF 1.304
Qi SONG,Jiaying CAI,Junjie ZHANG,Weiqiang YU,Feng WANG,Jie XU
Phenethyl phenyl ether (PPE) was selected as a typical lignin model compound and hydrogenated and cleaved over two readily accessible nickel-based catalysts, which could be easily separated from the product mixture. The results revealed that the reduction of the nickel catalyst with gaseous hydrogen produced a species capable of achieving higher activity towards C-O-C bond cleavage compared to the Ru/C and Pd/C catalysts. The selectivity of the C-O-C bond cleavage over the Ni/C catalyst was 85%, and higher than the corresponding values in the Ru/C (40%) and Pd/C (69%) systems. Using the carbothermal reduction method for the production of the Ni/C-C catalyst, the conversion and selectivity levels reached 99%, with 40% of the benzene rings in PPE being reserved. In comparison, no benzene ring containing products wer observed over the noble metal catalysts. This difference was attributed to the interaction between the carbon support and the nickel nanoparticles. 摘要 研究了Ni基催化剂上木质素模型化合物苯基苯乙醚中C–O–C键加氢裂解性能. 结果表明, 14;Ni/C催化剂显示出优异的加氢裂解能力, 14;苯基苯乙醚的转化率达到99%以上. Ni/C催化剂的还原方法对裂解选择性有重要影响; 氢气还原制备的Ni/C-H催化剂上, 14;C–O–C键裂解选择性为85%. Ru/C和Pd/C催化剂上裂解选择性分别为40%和69%. 采用碳热还原方法制备的Ni/C-C催化剂, 14;可以实现高选择性加氢和裂解, 14;C–O–C键裂解选择性达到99%以上, 14;其中芳烃化合物收率为44%. 这可能与镍组分和载体碳之间的相互作用有关.
研究领域:
化学工程
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催化科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
·
2021
·
IF 5.541
Fanggang Liu,Lijun Jin,Yanpeng Ban,Haoquan Hu
To understand the pyrolysis behavior of long linear alkanes, six n-alkanes (n-C n H 2n+2 , n = 10, 12, 13, 14, 15, 16) were conducted by pyrolysis coupled with photoionization molecular-beam mass spectrometer at pressure below 10 Pa and temperature between 200 °C and 1000 °C. Lots of important alkyl and alkenyl radicals (CH 3 , C 4 H 9 , C 8 H 15 , C 9 H 19 , C 3 H 5 , C 5 H 9 , etc.), which are the direct evidence to understand the pyrolysis reaction pathway, were real-time detected by mass spectral detector. The results suggested that the predominant pyrolysis mechanism of n-alkanes is a free-radical chain mechanism, beginning with the C C bond homolysis of n-C n H 2n+2 to produce primary alkyl radicals (C m H 2m+1 , m < n) and termination by β C-H homolysis and mutual combination of radicals. The chain is propagated by the β C-C homolysis and H-abstraction of primary alkyl radicals to produce secondary alkyl radicals (C h H 2h+1 ), and then the β C-C homolysis and H-abstraction of the secondary alkyl radicals to form alkyl/alkenyl radicals (C h H 2h+1 /C k H 2k-1 , h ≤ n, k < n-3) and alkenes (C k H 2k /C k H 2k-2 ) and the hydrogen-shift to form free-radical isomers. During the process, H-abstrction, and hydrogen-shift reactions exist as a synergistic reaction. In addition, the position of free radical in alkyl isomers is closer to the central carbon at low temperature. With the increase of temperature, 2-C m H 2m+1 radical are gradually dominated.
研究领域:
化学
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能源科学
✓ 已验证
产品关联
DOI
高影响因子
TOXICOLOGY
·
2021
·
IF 4.221
Aijing Bi,Zhen Guo,Guocui Yang,Youfang Huang,Zhimin Yin,Lan Luo
Cadmium (Cd) is a highly toxic environmental pollutant, leading to the occurrence and development of multiple neurological diseases. γ-glutamylcysteine (γ-GC) is a dipeptide formed by the condensation of l -glutamic acid and l -cysteine, which has antioxidant, anti-inflammatory, and chelating properties. The purpose of this study is to investigate the effect of γ-GC on Cd-induced apoptosis in PC12 cells. PC12 cells were pretreated with or without γ-GC (2 mM or 4 mM) for 2 h and exposed to Cd (10 μM) for 12 h, and survival, apoptosis, and oxidative stress of PC12 cells were detected after different treatments. The results showed that γ-GC significantly inhibited cell viability reduction, apoptosis, and depolarization of mitochondrial transmembrane potential in Cd-treated PC12 cells, as indicated by CCK-8 assay, flow cytometry, TUNEL staining, and JC-1 detection. Western blot showed that γ-GC down-regulated the ratio of Bax/Bcl-2 and the protein levels of cytosolic cytopigment c, cleaved-caspase-9, cleaved-caspase-3, and cleaved-PARP. Mechanistically, γ-GC suppressed Cd-induced ROS production, MDA accumulation, and GSH depletion, and increased the activity of antioxidant enzymes. Cd-induced activation of MAPK and PI3K/Akt signaling pathways were inhibited by γ-GC treatment, while sustained phosphorylation of JNK, p38, or Akt reversed anti-apoptotic effects of γ-GC. These results suggested that γ-GC inhibited Cd-induced apoptosis in PC12 cells through decreasing oxidative stress and inhibiting the activation of MAPK and PI3K/Akt signaling pathways. γ-GC could be used as a potential protective agent against Cd neurotoxicity.
研究领域:
神经毒理学
·
细胞生物学
·
药理学
·
毒理学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2023
·
IF 22.1
Weilin Tu,Mingyu Chu,Xianpeng Wang,Xuchun Wang,Yifan Li,Wenxiu Yang,Muhan Cao,Lu Wang,Youyong Li,Tsun-Kong Sham,Yi Cui,Qiao Zhang,Jinxing Chen
The in-depth mechanism of the emerging Ru-catalyzed polyolefin hydrogenolysis remains unclear. Here, we overcome this challenge by constructing a strong metal-support interaction (SMSI) system based on Ru/TiO 2 catalysts. With the increase of SMSI intensity, electrons are transferred from the TiO x capping layer to the Ru species. This effect facilitates the key steps of hydrogenation/desorption, while having little effect on the dehydrogenation and C–C cracking elementary reactions. As a result, the catalyst with higher hydrogenation capability prone to proceed hydrogenation and desorption step, thus suppressing cascade C–C cracking and avoiding the production of low value methane. The catalyst with the strongest SMSI effect exhibits a liquid fuel yield of 89.4% at ∼100% solid conversion. The SMSI effect also enables the catalysts with superior stability, so it can also efficiently upcycle commercial polyolefins. This work provides an in-depth understanding of the effects of metal-support interactions on polyolefin hydrogenolysis and paves the way for catalyst design.
研究领域:
催化化学
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材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Physical Chemistry C
·
2015
·
IF 4.772
Yuangang Li,Rongrong Wang,Huajing Li,Xiaoliang Wei,Juan Feng,Kaiqiang Liu,Yongqiang Dang,Anning Zhou
Co-Pi decorated TiO2@graphitic carbon nitrides (g-C3N4) nanorod arrays (denoted as CCNRs) with different mass ratios of g-C3N4 have been constructed on the FTO substrate through three processes, hydrothermal growth, chemical bath deposition and electrodeposition. First, TiO2 nanorod arrays were grown onto a FTO substrate by a hydrothermal method. Second, g-C3N4 was coated onto the TiO2 nanorod arrays by immersing the above substrate with TiO2 nanorod arrays into a solution of urea and then heated at higher temperature. In this procedure, the amount of the g-C3N4 on the TiO2 nanorod arrays can be controlled by tuning the concentration of the urea solution. At last, Co-Pi were decorated on the surface of the TiO2@g-C3N4 by electrodeposition. The as-prepared CCNRs were characterized by XRD, FESEM, TEM, XPS, UV–vis, and FTIR, respectively, which illustrated that Co-Pi moieties were successfully decorated on the hybrid TiO2@g-C3N4 nanorod arrays. Photoelectrochemical (PEC) measurements have demonstrated that the prepared CCNRs serve as an efficient and stable photoanode for PEC seawater splitting. The photocurrent density reaches 1.6 mA/cm2 under 100 mW/cm2 (AM1.5G) light illumination at 1.23 V (RHE). More significantly, the CCNRs photoanode is quite stable during seawater splitting and the performance remain undiminished even after 10 h continuous illumination. Finally, a systematical photocatalytic mechanism of the Co-Pi decorated TiO2@g-C3N4 was proposed, and it can be considered as potential explanation of enhanced PEC performance.
研究领域:
材料科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Chemistry C
·
2023
·Vol. 11
·期 35
·11960-11968
·
IF 6.4
Yin Huang,Guangzheng Xu,Xiaoyu Huang,Hao Wu,Xiuhua Wang
For hydrogen evolution via overall water splitting, conveniently linked hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) catalysts are greatly sought. Thus, a three-step growth-conversion approach is used to create a particular type of Co2V2O6·2H2O/ZIF-L@MXene/NF in order to create a bifunctional water splitting catalyst. The strong coupling between Co2V2O6·2H2O/ZIF-L as a precursor to produce OER active species and a MXene that promotes mass/charge transfer greatly improves the performance of the catalyst. The as-prepared Co2V2O6·2H2O/ZIF-L@MXene/NF exhibits a low OER overpotential of 224 mV@50 mA cm−2, an HER overpotential of 98 mV@10 mA cm−2, and an overall water splitting overpotential of 1.478 mV@10 mA cm−2. To accomplish total water splitting, the electrolyser can also be powered by a solar cell (1.5 V). This research will help to create non-noble metal-based electrocatalysts that are effective and economical.
研究领域:
材料科学
·
能源科学
✓ 已验证
产品关联
DOI
高影响因子
Microorganisms
·
2024
·Vol. 12
·期 7
·1381
·
IF 4.1
Xuezhi Shao,Hongliang Fang,Tao Li,Liyan Yang,Dengfeng Yang,Lixia Pan
Lytic polysaccharide monooxygenases (LPMOs) are copper-dependent enzymes that catalyze the oxidative cleavage of recalcitrant polysaccharides. There are limited reports on LPMOs capable of concurrently catalyzing the oxidative cleavage of both cellulose and chitin. In this study, we identified and cloned a novel LPMO from the newly isolated bacteriumChitinilyticum aquatileCSC-1, designated asCaLPMO10. When using 2, 6-dimethylphenol (2, 6-DMP) as the substrate,CaLPMO10 exhibited optimal activity at 50 °C and pH 8, demonstrating good temperature stability at 30 °C. Even after a 6 h incubation at pH 8 and 30 °C,CaLPMO10 retained approximately 83.03 ± 1.25% residual enzyme activity. Most metal ions were found to enhance the enzyme activity ofCaLPMO10, with ascorbic acid identified as the optimal reducing agent. Mass spectrometry analysis indicated thatCaLPMO10 displayed oxidative activity towards both chitin and cellulose, identifying it as a C1/C4-oxidized LPMO.CaLPMO10 shows promise as a key enzyme for the efficient utilization of biomass resources in future applications.
研究领域:
生物化学
·
微生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Frontiers of Chemical Science and Engineering
·
2022
·Vol. 16
·期 12
·1689-1699
·
IF 4.803
Li Wang,Li Wen-Ying,Wang Xing-Bao,Feng Jie
Radicals are important intermediates in direct coal liquefaction. Certain radicals can cause the cleavage of chemical bonds. At high temperatures, radical fragments can be produced by the splitting of large organic molecules, which can break strong chemical bonds through the induction pyrolysis of radicals. The reaction between the formation and annihilation of coal radical fragments and the effect of hydrogen-donor solvents on the radical fragments are discussed in lignite hydrogenolysis. Using the hydroxyl and ether bonds as indicators, the effects of different radicals on the cleavage of chemical bond were investigated employing density functional theory calculations and lignite hydrogenolysis experiments. Results showed that the adjustment of the coal radical fragments could be made by the addition of hydrogen-donor solvents. Results showed that the transition from coal radical fragment to H radical leads to the variation of product distribution. The synergistic mechanism of hydrogen supply and hydrogenolysis of hydrogen-donor solvent was proposed.
研究领域:
化学工程
·
物理化学
·
能源科学
✓ 已验证
DOI
高影响因子
BIOMASS & BIOENERGY
·
2024
·
IF 5.8
Linghui Kong,Yunyu Guo,Baihong Li,Yuewen Shao,Chao Li,Lijun Zhang,Zhihui Pan,Yuxuan Liu,Shu Zhang,Qiaoling Li,Xun Hu
Cracking reactions play essential roles in pore development of activated carbon (AC) during activation of a biomass feedstock with K 2 C 2 O 4 . Strengthening activity of activating agents for cracking might increase capability for creating pores. This was verified herein by conducting activation of poplar wood and its derived biochar by K 2 C 2 O 4 with Ni presence for enhancing activity for cracking. The results indicated that nickel species promoted cracking, decreasing substantially yield of AC by 41.4 % and abundance of organics in resulting bio-oils. Nonetheless, nickel presence remarkably enlarged pore volume (1.0 versus 0.7 cm 3 /g in control experiment without Ni) and average pore diameter (1.7 versus 1.0 nm), creating more mesopores (84.7 % versus 96.8 %) and macropores. Activation of poplar-derived biochar enhanced specific surface area (1167.4 versus 1033.4 m 2 /g) and also formation of mesopores (81.0 % versus 98.1 %) with nickel presence. Additionally, nickel also promoted dehydrogenation and deoxygenation, rendering AC of higher aromatic degree. However, some nickel species inserting skeleton of AC were difficult to be removed via acid washing, which blocked some pores. Nickel presence also led to more fragmented structure of AC in either activation of PW or the biochar, generating more larger pores with minimized steric hindrance for adsorption of large molecules like tetracycline.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）