Catalysts
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2019
·Vol. 9
·期 8
·648
·
IF 3.444
Xiao-Qing Gong,Chuan-Wan Wei,Jia-Kun Xu,Xiao-Juan Wang,Shu-Qin Gao,Ying-Wu Lin
The encapsulated enzyme system by metal-organic frameworks (MOFs) exhibits great potential in biofuel cells, pharmaceuticals, and biocatalysis. However, the catalytic efficiency and the enzymatic activity are severely hampered due to enzyme leaching and deficiency of storage stability. In this study, we immobilized cytochromec(Cytc) into dimethylimidazole-copper (Cu(Im)2) by biomimetic mineralization, and constructed a bioinorganic hybrid material, termed Cytc@Cu(Im)2. Encapsulated Cytcin Cu(Im)2with a nanosheet structure exhibited significantly improved catalytic efficiency, enzymatic activity and kinetic performance. The catalytic efficiency (kcat/Km) for Cytc@Cu(Im)2was ~20-fold higher compared to that of free Cytc. Moreover, the increased activity was not affected by long-term storage. Based on this system, we further constructed a multi-enzyme composite with glucose-oxidase (GOx), termed GOx-Cytc@Cu(Im)2, which exhibited greatly improved enzymatic activity, stability, and excellent selectivity for the detection of low concentrations of glucose. This strategy may provide new insights into the design of enzymes with high activity and stability, as well as the construction of multi-enzyme systems.Keywords:enzymatic immobilization;biomimetic mineralization;multi-enzyme;bioinorganic hybrid material;biosensors
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ChemCatChem
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2018
·Vol. 10
·期 24
·5619-5626
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IF 4.674
Xing Yu,Cunhui Zhou,Xinqing Chen,Peng Gao,Minghuang Qiu,Wenjie Xue,Chengguang Yang,Hanqin Zhao,Hongjiang Liu,Ziyu Liu,Yuhan Sun
Graphical CatalyZSM-5 : Well crystallized hollow fibers assembled by c -axis oriented ZSM-5 crystals were successfully synthesized via a facile one-pot solvent-free route, using quartz fiber as silicon substrate and NH 4 HCO 3 as the growing inhibitor on the crystal faces. The obtained ZSM-5 hollow fibers gave a hierarchical structures composed by micro-, meso- and macropores exhibiting excellent performance in methanol to gasoline (MTG) reaction with higher C 5+ selectivity and longer lifetime due to the improved mass transfer inside the unique hollow fiber structure. Well crystallized hollow fibers assembled by c -axis oriented ZSM-5 crystals were successfully synthesized via a facile one-pot solvent-free route, using quartz fiber as silicon substrate and NH 4 HCO 3 as the growing inhibitor on the crystal faces. The immigration of silica inside the quartz fibers formed the hollow morphology and the shell of hollow fiber was composed by the ZSM-5 crystals. In addition, the length of c -axis of ZSM-5 could be controlled by the amount of NH 4 HCO 3 , which selectively inhibited the growth on (010) surface. The obtained ZSM-5 hollow fibers gave a hierarchical structures composed by micro-, meso- and macropores. Catalytic tests for methanol to gasoline (MTG) revealed that the resultant ZSM-5 hollow fiber exhibited excellent performance with higher C 5+ selectivity and longer lifetime due to the improved mass transfer inside the unique hollow fiber structure.
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SYNTHESIS-STUTTGART
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2019
·Vol. 51
·期 16
·3085-3090
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IF 2.867
Menglan Wang,Yudong Li,Qing-An Wu,Shuping Luo,Yuehui Li
Indole scaffold synthesis relies primarily on oxidative C–H amination of N-protected alkenylanilines for C–N intramolecular cyclization reactions. Herein, for the first time, without N-protection, various readily prepared 2-alkenylanilines were transformed into the desired indole products in good yields by using K2S2O8 as oxidant in the presence of catalytic amounts of FeF2. The K2S2O8/FeF2 system offers a direct and benign synthetic route to 3-arylindoles and it is applicable to a wide range of substituted indoles including drug intermediates.
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Journal of Chemistry
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2018
·
IF 1.726
Zou Bin,Chen Xueshan,Xia Jiaojiao,Zhou Cunshan
Conversion of HMF into FDCA was carried out by a simple and green process based on alkaline ionic liquid (IL) modified Pd/C catalyst (Pd/C-OH−). Alkaline ionic liquids were chosen to optimize Pd/C catalyst for special hydrophilicity and hydrophobicity, redox stability, and unique dissolving abilities for polar compounds. The Pd/C-OH− catalyst was successfully prepared and characterized by SEM, XRD, TG, FT-IR, and CO2-TPD technologies. Loading of alkaline ionic liquid on the surface of Pd/C was 2.54 mmol·g−1. The catalyst showed excellent catalytic activity in the HMF oxidation after optimization of reaction temperature, reaction time, catalyst amount, and solvent. Supported alkaline ionic liquid (IL) could be a substitute and promotion for homogeneous base (NaOH). Under optimal reaction conditions, high HMF conversion of 100% and FDCA yield of 82.39% were achieved over Pd/C-OH− catalyst in water at 373 K for 24 h.
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JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
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2018
·
IF 3.046
Yong Li,Desheng Pan,Da Li,Yang Feng,C.J. Choi,Wei Liu,Zhidong Zhang
ε-Fe 3 N@C nanocrystals without oxidation are one-pot synthesized by using the iron(II) acetylacetonate and tetraethylenepentamine (TEPA) as Fe and N precursors under a low temperature (533 K) in the presence of a small quantity of Pt atoms as the co-catalyst. The ε-Fe 3 N@C nanoparticles with a core-shell structure are nearly spherical and have a wide particle size distribution of 100–500 nm in diameter. Fe nanoparticles obtained by reduction of Fe 2+ with TEPA are an effective catalyzer for decomposing TEPA to produce N and C atoms at a temperature much lower than the boiling point of TEPA. The diffusion of N atoms into Fe nanoparticles for the formation of ε-Fe 3 N@C is proposed, based on the results obtained by kinetically controlling the synthetic temperature and surfactants. The ε-Fe 3 N@C nanoparticles have an excellent saturation magnetization of 135.5 emu/g at room temperature. A significantly enhanced Curie temperature (T C ) of 614 K is reached in the present ε-Fe 3 N@C nanoparticles, which is much higher than the T C values in the previously reported ε-Fe 3 N x .
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ACS Applied Materials & Interfaces
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2018
·
IF 8.097
Xin Zhang,Zhuanghe Ren,Yunhao Lu,Jianhua Yao,Mingxia Gao,Yongfeng Liu,Hongge Pan
Herein, we synthesize successfully ultrafine TiN nanoparticles (<3 nm in size) embedded in N-doped carbon nanorods (nano-TiN@N–C) by a facile one-step calcination process. The prepared nano-TiN@N–C exhibits superior catalytic activity for hydrogen storage in NaAlH4. Adding 7 wt % nano-TiN@N–C induces more than 100 °C reduction in the onset dehydrogenation temperature of NaAlH4. Approximately 4.9 wt % H2 is rapidly released from the 7 wt % nano-TiN@N–C-containing NaAlH4 at 140 °C within 60 min, and the dehydrogenation product is completely hydrogenated at 100 °C within 15 min under 100 bar of hydrogen, exhibiting significantly improved desorption/absorption kinetics. No capacity loss is observed for the nano-TiN@N–C-containing sample within 25 de-/hydrogenation cycles because nano-TiN functions as an active catalyst instead of a precursor. A severe structural distortion with extended bond lengths and reduced bond strengths for Al–H bonding when the [AlH4]− group adsorbs on the TiN cluster is demonstrated for the first time by density functional theory calculations, which well-explains the reduced de-/hydrogenation temperatures of the nano-TiN@N–C-containing NaAlH4. These findings provide new insights into designing and synthesizing high-performance catalysts for hydrogen storage in complex hydrides.
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FUEL PROCESSING TECHNOLOGY
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2018
·
IF 3.956
Lele Jin,Wenzhi Li,Qiying Liu,Jindong Wang,Yuanshuai Zhu,Zhenhang Xu,Xiangqian Wei,Qi Zhang
A catalytic routine was developed for kraft lignin depolymerization in dioxane-water systems, in which the catalyst HTaMoO 6 with strong Bronsted acidity and a hydrogenation catalyst (Rh/C) were employed simultaneously. The performance of the composite catalysts was tested in a series of experiments with various reaction temperatures, reaction time and catalyst ratios. Under the optimized conditions, a higher petroleum ether soluble fraction yield of 58.7% was obtained at 320 °C for 24 h. Besides, a higher liquid product yield of 95.6% was achieved at 290 °C for 2 h. Specially, the main compositions of the petroleum ether soluble fraction are monomers and dimers, which can be used as liquid fuel. These results demonstrated that the composite catalyst HTaMoO 6 -Rh/C can effectively catalyze the depolymerization of the kraft lignin into small molecule liquid fuel components.
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ACS Catalysis
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2018
·
IF 11.384
Yizhou Wu,Jesse Ward-Bond,Donglin Li,Shaohua Zhang,Jiafu Shi,Zhongyi Jiang
Graphitic carbon nitride (g-C3N4) is an emergent metal-free photocatalyst because of its band position, natural abundance, and facile preparation. Synergetic intensification of charge generation and charge transfer of g-C3N4 to increase solar-to-chemical efficiency remains a hot yet challenging issue. Herein, a nanoshell with two moieties of α-Fe2O3 and carbon (C) is in situ formed on the surface of a g-C3N4 core through calcination of Fe3+/polyphenol-coated melamine, thus acquiring g-C3N4@α-Fe2O3/C core@shell photocatalysts. The α-Fe2O3 moiety acts as an additional photosensitizer, offering more photogenerated electrons, whereas the C moiety bridges a “highway” to facilitate the electron transfer either from α-Fe2O3 moiety to g-C3N4 or from g-C3N4 to C moiety. By tuning the proportion of these two moieties in the nanoshell, a photocurrent density of 3.26 times higher than pristine g-C3N4 is obtained. When utilized for photocatalytic regeneration of reduced nicotinamide adenine dinucleotide (NADH, a dominant cofactor in biohydrogenation reaction), g-C3N4@α-Fe2O3/C exhibits an equilibrium NADH yield of 76.3% with an initial reaction rate (r) of 7.7 mmol h–1 g–1, among the highest r for photocatalytic NADH regeneration ever reported. Manipulating the coupling between charge generation and charge transfer may offer a facile, generic strategy to improve the catalytic efficiency of a broad range of photocatalysts other than g-C3N4.
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ELECTROCHIMICA ACTA
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2018
·
IF 5.116
Zhongliang Deng,Qingfeng Yi,Guang Li,Yao Chen,Xiaokun Yang,Huidong Nie
One of the major challenges towards the development of the conventional alkaline Zn-air battery is its spontaneous discharge caused by the unstability of the anode Zn in concentrated alkaline electrolyte . Utilization of a neutral electrolyte as the alternative to alkaline electrolyte is likely to be a promising strategy to overcome this issue because of much high stability of anode Zn in neutral solution. To realize the normal operation of the neutral Zn-air battery however, a crucial issue is how to ensure that the cathodic catalyst can efficiently electro-catalyze oxygen reduction reaction (ORR) in neutral solution. Herein, we report a facile preparation of Ni/Co-doped C-N nano-composite catalysts (NiCo/C-N) from direct pyrolysis of Ni/Co salt, polyaniline (PANI), carbon nanotube (CNT) and dicyandiamide. Among the as-synthesized catalysts, Ni 1 Co 3 /CN-3 presents high and stable ORR current density of 5.27 mA cm −2 in 0.5 mol L −1 KNO 3 solution at 2000 rpm. Electron transfer number of ORR on Ni 1 Co 3 /CN-3 catalyst is 3.78, showing a nearly completed reduction of O 2 to H 2 O. A neutral Zn-air battery with the prepared NiCo/C-N composite coated on carbon paper as the air electrode catalyst and metal Zn as the anode was constructed in 0.5 mol L −1 KNO 3 solution. For the catalyst Ni 1 Co 3 /CN-3, the open circuit voltage of the neutral Zn-air battery is 1.16 V, and the maximum power density is 38.5 mW cm −2 . The galvanostatic discharge time is 345.7, 160.6, 18.1 and 1.3 h as the discharge current density keeps 10, 50, 100 and 150 mA cm −2 respectively. A stable voltage plateau arises at various discharge current densities. The neutral Zn-air battery can repeatedly discharge after the zinc anode has been replaced, indicating that the synthesized ORR catalyst is an excellent cathode material for the neutral Zn-air battery. This kind of neutral Zn-air battery has a wide application prospect as mobile power supply.
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Nanoscale
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2018
·Vol. 10
·期 24
·11418-11429
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IF 7.233
Yuxia Pei,Menghuan Li,Yanhua Hou,Yan Hu,Guangyu Chu,Liangliang Dai,Ke Li,Yuxin Xing,Bailong Tao,Yonglin Yu,Chencheng Xue,Ye He,Zhong Luo,Kaiyong Cai
The precise tumor cell-specific delivery of therapeutic proteins and the elimination of side effects associated with routine chemotherapeutic agents are two current critical considerations for tumor therapy. In this study, we report a reactive oxygen species (ROS)-activated yolk–shell nanoplatform for the tumor-specific co-delivery of cytochrome c (Cyt c) prodrug and doxorubicin, in which the bioactivity of Cyt c could be restored by the intracellular ROS-trigger and readily initiate the sequential doxorubicin release. The DOX-loaded lactobionic acid-modified yolk–shell mesoporous silica nanoparticles were first encapsulated with 4-nitrophenyl 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzyl carbonate (NBC)-modified Cyt c via boronic ester linkages, and functionalized again with lactobionic acid to further shield Cyt c and confer the selective tumor targeting against liver cancer cells. The key feature in this design is that by taking advantage of the boronic ester linkage, the cytotoxicity of Cyt c capped on the nanoparticle could be temporarily deactivated during blood transportation and rapidly restored upon exposure to the ROS-rich microenvironment within liver cancer cells, thereby simultaneously achieving the protein therapy and stimuli-responsive doxorubicin release. This study presents a novel strategy for the development of tumor-sensitive co-delivery nanoplatforms.
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高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
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2018
·Vol. 136
·期 10
·47170
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IF 1.901
Hui Zhang,Hao Yang,Baoqing Shentu
Surface modification of titanium dioxide (TiO 2 ) nanoparticles (NPs) by silane coupling agents and the ultraviolet-C (UV-C) aging behavior of silicone rubber (SiR) incorporated with the modified TiO 2 NPs were investigated in this work. The SiR samples incorporated with TiO 2 NPs displayed excellent stability against the UV-C radiation. In order to improve the dispersion of TiO 2 NPs in the SiR matrix, the surface of TiO 2 NPs was modified with 3-aminopropyl triethoxysilane and 3-trimethoxysilyl propyl methacrylate, respectively. The surface modification of TiO 2 NPs was characterized by thermal gravimetric analysis and Fourier transform infrared spectroscopy. The dispersion stability of the pristine TiO 2 NPs and surface silane-modified TiO 2 NPs was evaluated in an organic solvent (toluene). Effect of surface modified TiO 2 NPs on the UV-C aging behavior of SiR was evaluated in terms of the change of surface morphology, tensile properties, hardness, crosslinking density, and surface microstructure before and after the UV-C aging. The results showed that surface modification of TiO 2 NPs with silane coupling agents could improve the dispersion of TiO 2 NPs in the SiR matrix. Moreover, the SiR with modified TiO 2 NPs showed an improved aging resistance to the UV-C radiation, compared with the samples with pristine TiO 2 NPs. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136 , 47170.
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JOURNAL OF CATALYSIS
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2018
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IF 6.759
Jinping Zhang,Shinichi Nagamatsu,Junmou Du,Chaoli Tong,Huihuang Fang,Dehui Deng,Xi Liu,Kiyotaka Asakura,Youzhu Yuan
Transition-metal nitrides can exhibit catalytic performance comparable to that of noble metal catalysts in many reactions. However, investigations on the correlation of catalyst structure, performance, and stability are still highly demanded. Here, a series of metal nitrides were prepared and evaluated for the selective oxidation of alcohols by molecular oxygen. Among them, FeN x /C- T catalysts ( T represents the pyrolysis temperature) display above 95% selectivity to the corresponding aldehydes in the selective oxidation of unsaturated alcohols. The optimized FeN x /C-900 catalyst gives the highest TOF of 7.0 h −1 for the conversion of 5-hydroxymethylfurfural to 2,5-diformylfuran. A combination of characterizations and experiments suggests that Fe N 4 species are the main active sites. In addition, we investigate the reasons for the catalyst deactivation and provide an effective approach to regenerating the catalysts. The results indicate that the deactivated catalysts can be regenerated by heat treatment under NH 3 /N 2 after each run. Based on these studies, a plausible reaction mechanism over the FeN x /C catalysts is proposed.
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