CHINESE JOURNAL OF CATALYSIS
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2014
·
IF 1.552
Guoqiang Song,Zhiqing Wang,Liang Wang,Guoru Li,Minjian Huang,Fengxiang Yin
Effective bifunctional catalysts play a vital role in large-scale commercial applications of rechargeable lithium-air batteries. In this article, a metal-organic framework, MOF(Fe), was prepared by a hydrothermal process using ferric nitrate as the metal ion precursor and trimesic acid as an organic ligand. The structure of the MOF(Fe) was characterized by X-ray diffraction, N 2 adsorption-desorption, Transmission electron microscopy, Fourier transform infrared spectroscopy and Thermo-gravimetric analysis. The activity for the oxygen reduction reaction (ORR) and the kinetic behavior of the ORR using the MOF(Fe) were investigated by cyclic voltammetry and rotating disk electrode voltammetry, respectively, using an alkaline electrolyte. The characterization results showed that the MOF(Fe) was highly crystalline with abundant micropores, large specific surface area and high thermal stability. The MOF(Fe) exhibited excellent catalytic activity for the ORR. The ORR mechanism varies with the applied potentials. The ORR occurs through a two-electron pathway at potentials in the range of −0.30 to −0.50 V, but shifts to four-electron pathway with the potentials in the range −0.50 to −0.95 V. In addition, the MOF(Fe) shows excellent catalytic activity for the oxygen evolution reaction (OER) in an alkaline electrolyte. This work opens a new route for the development of effective non-precious metal catalysts based on MOFs for the ORR and OER.
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高影响因子
CHINESE JOURNAL OF CATALYSIS
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2014
·
IF 1.552
Zhongyi An,Yuqun Zhuo,Chao Xu,Changhe Chen
Mn-based catalysts impregnated on TiO 2 with different crystalline phases (rutile (R), anatase (A), and P25 (P)) were studied for the oxidation of NO to NO 2 . 10%MnO x /TiO 2 (P) was the most active catalyst, giving 83% of NO conversion at 300 °C and a GHSV of 20000 h −1 . The catalyst activities were in the order MnO x /TiO 2 (P) > MnO x /TiO 2 (A) > MnO x /TiO 2 (R). The catalysts were characterized by X-ray diffraction, field emission scanning electron microscopy, X-ray photoelectron spectroscopy, H 2 temperature-programmed reduction, and O 2 temperature-programmed desorption. Compared to anatase and rutile, P25 gave better dispersion of MnO x on the support surface, suppressed the agglomeration of catalyst particles, and also produced more Mn 2 O 3 , which was more active for the oxidation of NO. In addition, P25 enhanced the reduction of MnO x , especially for Mn 2 O 3 , and the formation of easily desorbed O 2 − generated from the Mn 3+ –O bond.
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高影响因子
CHINESE JOURNAL OF CATALYSIS
·
2014
·
IF 1.552
Li Meng,Fangzhong Wang,Ao Wang,Jian Pu,Bo Chi,Jian Li
La 0.8 Sr 0.2 MnO 3 (LSM)-coated Ba 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3 (BSCF) composite powder (LSM-BSCF) was synthesized by a novel solid-solution method and investigated electrochemically as a cathode material for intermediate temperature solid oxide fuel cells. The cathode combined the merits of LSM and BSCF cathodes through an extended triple phase boundary and stabilized microstructure and demonstrated a polarization resistance between 0.61 and 0.09 Ω cm 2 at 600 to 750 °C. Compared with high performance cathodes prepared by solution impregnation, this LSM-BSCF cathode greatly improved performance stability.
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高影响因子
JOURNAL OF RARE EARTHS
·
2014
·
IF 1.342
Xiaodong WU,Haining YU,Duan WENG,Shuang LIU,Jun FAN
MnO and CeO 2 powders were mechanically mixed by a spatula and by milling to obtain loose-contact and tight-contact mixed oxides, respectively. The monoxides and their physical mixtures were characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), X-ray photoelectron spectroscopy (XPS), Raman, O 2 temperature-programmed desorption (O 2 -TPD), H 2 temperature-programmed reduction (H 2 -TPR) and NO temperature-programmed oxidation (NO-TPO). The MnO x -CeO 2 solid solutions did not form without any calcination process. The oxidation state of manganese tended to increase while the ionic valence of cerium decreased in the mixed oxides, accompanied with the formation of oxygen vacancies. This long-ranged electronic interaction occured more significantly in the tight-contact mixture of MnO and CeO 2 . The formation of more Mn 4+ and oxygen vacancies promoted the catalytic oxidation of NO in an oxygen-rich atmosphere.
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高影响因子
CHINESE JOURNAL OF CATALYSIS
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2013
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IF 1.304
Qian Mi,Daiquan Chen,Juncheng Hu,Zhengxi Huang,Jinlin Li
A novel N-doped graphene/CdS hollow sphere nanocomposite photocatalyst was synthesized by a simple, template-free one-pot method. The samples were characterized by X-ray diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy, ultraviolet-visible diffuse reflectance spectroscopy, N 2 adsorption-desorption, photoluminescence spectroscopy, and X-ray photoelectron spectroscopy. Photocatalytic degradations of methylene blue and salicylic acid were carried out to evaluate the photocatalytic activity of the nanocomposites under visible light irradiation. The N-graphene/CdS nanocomposites exhibited excellent stability and high photocatalytic activity, exceeding those of graphene oxide/CdS hollow sphere nanocomposites and pure CdS hollow spheres. This excellent photocatalytic activity of the nanocomposite was due to N-graphene acting as an excellent electron acceptor and transporter, thus reducing charge carrier recombination. It was also found that • OH acted as the main reactive species in the degradation of methylene blue under visible-light irradiation.
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高影响因子
CHINESE JOURNAL OF CATALYSIS
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2013
·
IF 1.304
Ying Liu,Yangcheng Lü,Guangsheng Luo
A phosphine-functionalized polystyrene microcapsule with hundreds of microns in size was prepared using a microfluidic platform. The size distribution was narrow and the average size could be adjusted in the range 300-400 μm. The morphology and composition of the microcapsules were characterized using scanning electron microscopy, energy-dispersive X-ray spectroscopy, and inductively coupled plasma atomic emission spectroscopy. The results verified the effectiveness of the strategy we proposed for preparing uniform microcapsules with stable Pd immobilization. A Suzuki coupling reaction between aryl halides and phenylboronic acid was used as the model to evaluate their catalytic activity after Pd(PPh 3 ) 4 immobilized onto the microcapsule. It was found that the catalytic activity of microcapsule-supported Pd was always higher than that of the corresponding homogeneous catalyst, and was similar with that of the literature reported microcapsule-supported catalyst with about 7-8 μm particle size. Microcapsule-supported Pd with microcapsules of hundreds of microns in size, being easy to recover, showed good reusability and undetected active species loss, its productivity effect and controllability of the microcapsule-supported Pd catalyst were also expected to benefit from continuous preparation using the microfluidic platform. Moreover, they could be potentially exploited in a fixed-bed reactor with high catalyst density and good mechanical stability.
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高影响因子
CHINESE JOURNAL OF CATALYSIS
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2013
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IF 1.304
Yi Hu,Xiangjun Jiang,Suwen Wu,Ling Jiang,He Huang
Vitamin E succinate was synthesized by interfacial activated Candida rugosa lipase (CRL) encapsulated in sol-gel materials. The effects of various immobilization parameters were investigated. The optimum conditions were found to consist of n -propyltrimethoxysilane/tetraethoxysilane molar ratio = 1/1, water/silane molar ratio ( R value) = 20, lipase loading = 0.5 mg/ml sol, and PEG400 loading = 12 μl/ml sol. Compared with free enzymes, sol-gel encapsulated enzymes kept its activity of 70.58% and achieved 2.6-fold increased stability after 18 h incubation in phosphate buffer (0.025 mol/L, pH = 7.0) at 50 °C. Based on the interfacial characteristics of CRL, five kinds of surfactants were used for activation. The results demonstrate that olive oil was the most effective in activating CRL. The esterification activity of vitamin E succinate synthesis by interfacial activated CRL encapsulated in sol-gel materials reached up to 6.7-fold and 1.43-fold that of free enzyme and non-interfacial activated enzyme, respectively.
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高影响因子
JOURNAL OF RARE EARTHS
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2013
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IF 1.363
Hongzhen XIE,Guanzhong LU
Five lanthanide complexes of Ln 2 (dpdc) 2 (tpy) 2 (NO 3 ) 2 (H 2 O) 2 [Ln=La ( 1 ), Ce ( 2 ), Pr ( 3 ), Sm ( 4 ), Gd ( 5 ), H 2 dpdc=2,2’-biphenyldicarboxylic acid and tpy=2,2′:6′,2″-terpyridine] were prepared at room temperature and characterized by X-ray diffraction, FT-IR and thermo-gravimetric analysis. The results showed that complexes 1–5 were isostructural and consisted of dinuclear units [Ln 2 (dpdc) 2 (tpy) 2 (NO 3 )(H 2 O) 2 ] bridged by two dpdc 2− ligands. The dinuclear units with strong intramolecular hydrogen bonds were assembled into 2D supramolecular layers by the weak π … π staking interactions between pyridine rings of tpy. The TG analysis showed that the complexes 1 – 5 behaved higher thermal stability with no mass loss at < 320 °C. The lanthanide contraction effect and the solid state luminescence properties of complexes 1 – 5 were also investigated. The luminescence emission spectra of complexes 1 – 5 exhibited ligands emission bands and complex 3 and 4 had no typical emission in the visible region.
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高影响因子
Journal of Environmental Sciences
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2013
·
IF 1.773
Liping Hao,Fan Lü,Lei Li,Liming Shao,Pinjing He
To use the selective inhibition method for quantitative analysis of acetate metabolism in methanogenic systems, the responses of microbial communities and metabolic activities, which were involved in anaerobic degradation of acetate, to the addition of methyl fluoride (CH 3 F), 2-bromoethanesulfonate (BES) and hydrogen were investigated in a thermophilic batch experiment. Both the methanogenic inhibitors, i.e., CH 3 F and BES, showed their effectiveness on inhibiting CH 4 production, whereas acetate metabolism other than acetoclastic methanogenesis was stimulated by BES, as reflected by the fluctuated acetate concentration. Syntrophic acetate oxidation was thermodynamically blocked by hydrogen (H 2 ), while H 2 -utilizing reactions as hydrogenotrophic methanogenesis and homoacetogenesis were correspondingly promoted. Results of PCR-DGGE fingerprinting showed that, CH 3 F did not influence the microbial populations significantly. However, the BES and hydrogen notably altered the bacterial community structures and increased the diversity. BES gradually changed the methanogenic community structure by affecting the existence of different populations to different levels, whilst H 2 greatly changed the abundance of different methanogenic populations, and induced growth of new species.
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PubMed
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.
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Materials Research Express
·
2015
·Vol. 2
·期 12
·125901
·
IF 0
Na Wu,Qun Luo,Xvsheng Qiao,Chang-Qi Ma
Recently, spectra conversion has been used to minimize energy loss in photovoltaic devices. In this work, we explore the development of a novel Eu3+-doped ZnO bi-functional layer for use in organic solar cells. The bi-functional layer acts as both a spectra conversion and an electron transporting layer. Compared to conventional spectra conversion layers, it has a simpler device structure, is easier to fabricate, and has a wider spectrum-sensitized region. A series of Eu3+-doped ZnO nanocrystals were synthesized using the simple solution route. X-ray powder diffraction patterns (XRD), transmission electron microscopy (TEM), and UV-visible absorbance spectra were used to characterize the obtained ZnO nanocrystals. The results reveal that the size and bandgap of ZnO nanocrystals can be controlled through regulation of the doping concentration of Eu3+ ions. The energy transfer of ZnO → Eu3+ is observed by photoluminescence (PL) spectra. At a bandgap excitation of around 300–400 nm, a typical emission band from the Eu3+ is obtained. By employing the Eu3+- doped ZnO nanocrystals as a buffer layer in a P3HT:PC61BM bulk heterojunction device, the obtained performance is similar to the undoped ZnO device, indicating that the electrical properties of ZnO are not affected by Eu3+ doping. Due to the down-conversion energy transfer between ZnO and Eu3+, the external quantum efficiency of the ZnO:Eu3+ device at 300–400 nm is higher than that of the pure ZnO device, which subsequently leads to an increase in short circuit current density (JSC). This work proves that it is possible to improve the solar spectrum response in the ultraviolet region of organic solar cells effectively by incorporating the bi-functional layer.
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NANOTECHNOLOGY
·
2016
·Vol. 27
·期 12
·125601
·
IF 3.573
Meili Yin,Zhenhua Li,Li Zhou,Kai Dong,Jinsong Ren,Xiaogang Qu
Recently, antibiotic drug-resistant therapies have become very important due to the emergence of antibiotic-resistant bacterial strains. The development of novel antibacterial materials has received significant attention. Here, quaternized chitosan hydrogels incorporated with NaYF4:Er/Yb/Mn@photosensitizer-doped silica (UCNPs/MB) were synthesized for effective killing of both gram-positive oxacillin-resistant S. aureus (DR-S. aureus) and gram-negative kanamyclin-resistant E. coli (DR-E. coli) bacteria upon near-infrared (NIR) laser irradiation. In this system, the cationic macroporous nature of the hydrogel acts as a molecular 'anion sponge', which sucks the outer part of the anionic microbe membrane into the gel interior voids and causes microbe membrane disruption. By incorporating UCNPs/MB-doped silica into the hydrogel, we have combined photodynamic therapy (PDT) with quaternized chitosan to obtain a high therapeutic index via a synergistic effect. In vitro experiments have demonstrated that our system had excellent antibacterial efficiency to both DR-S. aureus and DR-E. coli bacteria. More importantly, our new synergistic treatment modality provided an excellent therapy platform for drug-resistant bacteria, which could improve antimicrobial efficiency.
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高影响因子
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