With the significant discharge of antibiotic wastewater into the aquatic and terrestrial ecosystems, antibiotic pollution has become a serious problem and presents a hazardous risk to the environment. To address such ...With the significant discharge of antibiotic wastewater into the aquatic and terrestrial ecosystems, antibiotic pollution has become a serious problem and presents a hazardous risk to the environment. To address such issues, various investigations on the removal of antibiotics have been undertaken. Photocatalysis has received tremendous attention owing to its great potential in removing antibiotics from aqueous solutions via a green, economic, and effective process. However, such a technology employing traditional photocatalysts suffers from major drawbacks such as light absorption being restricted to the UV spectrum only and fast charge recombination. To overcome these issues, considerable effort has been directed towards the development of advanced visible light-driven photocatalysts. This mini review summarises recent research progress in the state-of-the-art design and fabrication of photocatalysts with visible-light response for photocatalytic degradation of antibiotic wastewater. Such design strategies involve the doping of metal and non-metal into ultraviolet light-driven photocatalysts, development of new semiconductor photocatalysts, construction of heterojunction photocatalysts, and fabrication of surface plasmon resonance-enhanced photocatalytic systems. Additionally, some perspectives on the challenges and future developments in the area of photocatalytic degradation of antibiotics are provided.展开更多
The complicated reaction mechanism and the character of competitive reactions lead to a stringent requirement for the catalyst of C_4 alkylation process. Due to their unique properties, ionic liquids(ILs) are thought ...The complicated reaction mechanism and the character of competitive reactions lead to a stringent requirement for the catalyst of C_4 alkylation process. Due to their unique properties, ionic liquids(ILs) are thought to be new potential acid catalysts for C_4 alkylation. An analysis of the regular and modified chloroaluminate ILs, novel Br?nsted ILs and composite ILs used in isobutane/butene alkylation shows that the use of either ILs or ILs coupled with mineral acid as homogeneous catalysts can help to greatly adjust the acid strength. By modifying the structural parameters of the cations and anions of the ILs, the solubility of the reactants could also be adjusted, which in turn displays a positive effect on improving the activity of ILs. Immobilization of ILs is an effective way to modulate the surface adsorption/desorption properties and acid strength distribution of the solid acid catalysts. Such a process has a tremendous potential to reduce the deactivation of catalyst and enhance the activity of the solid acid catalyst. The development of novel acid catalysts for C_4 alkylation is a comprehensive consideration of acid strength and its distribution, interfacial properties and transport characteristics.展开更多
A series of quaternary ammonium ionic liquids(ILs)were synthesized and employed as catalysts for the production of poly(isosorbide carbonate)(PIC)from diphenyl carbonate and isosorbide via a melt polycondensation proc...A series of quaternary ammonium ionic liquids(ILs)were synthesized and employed as catalysts for the production of poly(isosorbide carbonate)(PIC)from diphenyl carbonate and isosorbide via a melt polycondensation process.The relationship between the anions of the ILs and the catalytic activities was investigated,and the readily‐prepared IL tetraethylammonium imidazolate(TEAI)was found to exhibit the highest catalytic activity.After optimizing the reaction conditions,a PIC with a weight‐average molecular weight(Mw)of25600g/mol was obtained,in conjunction with an isosorbide conversion of92%.As a means of modifying the molecular flexibility and thermal properties of the PIC,poly(aliphatic diol‐co‐isosorbide carbonate)s(PAIC)s were successfully synthesized,again using TEAI,and polymers with Mw values ranging from29000to112000g/mol were obtained.13C NMR analyses determined that the PAIC specimens had random microstructures,while differential scanning calorimetry demonstrated that each of the PAICs were amorphous and had glass transition temperatures ranging from50to115°C.Thermogravimetric analyses found Td‐5%values ranging from316to332°C for these polymers.Based on these data,it is evident that the incorporation of linear or cyclohexane‐based diol repeating units changed the thermal properties of the PIC.展开更多
Electrochemical (EC) reactions play vital roles in many disciplines, and its molecular-level understanding is highly desired, in particular under reactions. The vibration spectroscopy is a powerful in situ technique...Electrochemical (EC) reactions play vital roles in many disciplines, and its molecular-level understanding is highly desired, in particular under reactions. The vibration spectroscopy is a powerful in situ technique for chemical analysis, yet its application to EC reactions is hindered by the strong attenuation of infrared (IR) light in both electrodes and electrolytes. Here we demonstrate that by incorporating appropriate sub-wavelength plasmonic structures at the metal electrode, the IR field at the EC interface can be greatly enhanced via the excitation of surface plasmon. This scheme facilitates in situ vibrational spectroscopic studies, especially using the surface-specific sum-frequency generation technique.展开更多
Narrow-band BiOI photocatalysts usually suffer from low photocatalysis efficiency under visible light exposure because of rapid charge recombination. In this work, to overcome this deficiency of photosensitive BiOI, o...Narrow-band BiOI photocatalysts usually suffer from low photocatalysis efficiency under visible light exposure because of rapid charge recombination. In this work, to overcome this deficiency of photosensitive BiOI, oxygen vacancies, Bi particles, and Bi2O2CO3 were co-induced in BiOI via a facile in situ assembly method at room temperature using NaBH4 as the reducing agent. In the synthesized ternary Bi/BiOI/(BiO)2CO3, the oxygen vacancies, dual heterojunctions (i.e., Bi/BiOI and Bi- OI/(BiO)2CO3), and surface plasmon resonance effect of the Bi particles contributed to efficient electron-hole separation and an increase in charge carrier concentration, thus boosting the overall visible light photocatalysis efficiency. The as-prepared catalysts were applied for the removal of NO in concentrations of parts per billion from air in continuous air flow under visible light illumination. Bi/BiOI/(BiO)2CO3 exhibited a highly enhanced NO removal ratio of 50.7%, much higher than that of the pristine BiOI (1.2%). Density functional theory calculations and experimental results revealed that the Bi/BiOI/(BiO)2CO3 composites promoted the production of reactive oxygen species for photocatalytic NO oxidation. Thus, this work provides a new strategy to modify narrow-band semiconductors and explore other bismuth-containing heterostructured visible-light-driven photocatalysts.展开更多
In this work,a novel plasmon-assisted UV-vis-NIR-driven W_(18)O_(49)/Cd_(0.5)Zn_(0.5)S heterostructure photocatalyst was obtained by a facile ultrasonic-assisted electrostatic self-assembly strategy.The hybrid exhibit...In this work,a novel plasmon-assisted UV-vis-NIR-driven W_(18)O_(49)/Cd_(0.5)Zn_(0.5)S heterostructure photocatalyst was obtained by a facile ultrasonic-assisted electrostatic self-assembly strategy.The hybrid exhibits extraordinary H2 evolution activity of 147.7 mmol·g^(-1)·h^(-1) at room temperature due to the efficient charge separation and expanded light absorption.Our investigation shows that the unique Step-scheme(S-scheme)charge transfer and the‘hot electron’injection are both responsible for the extraordinary H2 evolution process,depending on the wavelength of the incident light.Moreover,by accelerating the surface reaction kinetics,the activity can be further elevated to 306.1 mmol·g^(-1)·h^(-1),accompanied by a high apparent quantum yield of 45.3% at 365±7.5 nm.This work provides us a potential strategy for the highly efficient conversion of the solar energy by elaborately combining a nonstoichiometric ratio plasmonic material with an appropriate active photocatalyst.展开更多
The aromaticity of all possible substituted fullerene isomers of C18N2, C18B2, C18BN, and their molecular ions which originate from the C20 (Ih) cage were studied by the topological resonance energy (TRE) and the ...The aromaticity of all possible substituted fullerene isomers of C18N2, C18B2, C18BN, and their molecular ions which originate from the C20 (Ih) cage were studied by the topological resonance energy (TRE) and the percentage topological resonance energy methods. The relationship between the aromaticity of C18BxNy isomers and the sites where the heteroatoms dope at the C20 (Ih) cage is discussed. Calculation results show that at the neutral and cationic states all the isomers are predicted to be antiaromatic with negative TREs, but their polyvalent anions are predicted to be aromatic with positive TREs. The most stable isomer is formed by heteroatom doping at the 1,11-sites in C18N2. C18B2, and C18BN. Heterofullerenes are more aromatic than C20. The stability order in the neutral states is C18N2〉C18BN〉C18B2〉C20. The stability order in closed-shell is C18B2^8- 〉C20^6- 〉C18BN^6- 〉C18N2^4-. This predicts theoretically that their polyvalent anions have high aromaticity.展开更多
The cis and trans isomers separation of 2-butene-1,4-diol and lafutidine were studied by HPLC on two kinds of chiral columns: (S,S)-Whelk-O 1 and ChiraSpher. The isomers of 2-butene-1,4-diol can be separated on both c...The cis and trans isomers separation of 2-butene-1,4-diol and lafutidine were studied by HPLC on two kinds of chiral columns: (S,S)-Whelk-O 1 and ChiraSpher. The isomers of 2-butene-1,4-diol can be separated on both chiral columns while the isomers of lafutidine can only be resolved on ChiraSpher column. The influence of different type and amount of mobile phase modifier on the isomers separation was extensively studied. The resolution of cis and trans isomers of 2-butene-1,4-diol was 2.61on (S,S)-Whelk-O 1 column with hexane-ethanol (97:3, v/v) as the mobile phase. The resolution of lafutidine was 1.89 on ChiraSpher column with hexane-ethanol-THF-diethylamine (92:3:5:0.1, v/v/v/v) as the mobile phase. LC-MS methods were developed to identify the isomer peaks.展开更多
Chiral ionic liquids (CILs) containing imidazolium cations and L-Proline (L-Pro) anions were applied as chiral selector to separate tryptophan (Trp) enantiomers on a C18 column by ligand exchange chromatography. Sever...Chiral ionic liquids (CILs) containing imidazolium cations and L-Proline (L-Pro) anions were applied as chiral selector to separate tryptophan (Trp) enantiomers on a C18 column by ligand exchange chromatography. Several factors influencing Trp enantiomers separation, such as alkyl chain length of CILs, concentrations of Cu2+ and CILs, pH of the mobile phase, flow rate, organic solvent and temperature, were studied. Under the optimal conditions, the Trp enantiomers could be successfully separated within 21 min with the resolution of 2.30. At the same time, some thermodynamical parameters were obtained. The experimental results show that the enthalpy values of the Trp enantiomers are negative, indicating that the separation process is exothermic. And the enthalpy values of D-Trp are larger than those of L-Trp, which indicates that L-Trp could form more stable ternary complexes with tryptophan enantiomers.展开更多
In the present paper, we investigate the quantum phase transition in a spatially anisotropic antiferrornagnetic Heisenberg model of S =1 with single-ion energy anisotropy. By using the Schwinger boson representation, ...In the present paper, we investigate the quantum phase transition in a spatially anisotropic antiferrornagnetic Heisenberg model of S =1 with single-ion energy anisotropy. By using the Schwinger boson representation, we calculate the Gaussian correction to the critical value J⊥^c caused by quantum spin fluctuations. We find that, for the positive single-ion energy, a nonzero value of J⊥^c is always needed to stabilize the antiferromagnetic long-range order in this model. It resolves a difference among literature and shows clearly that the effect of quantum fluctuations may qualitatively change a result obtained by the mean-field theories on lower-dimensional systems.展开更多
Nanoscale spatial heterogeneity in ionic liquids is formed by the aggregation of cationic tail groups. The electrostatic interactions between polar groups and the collective van der Waals interactions between nonpolar...Nanoscale spatial heterogeneity in ionic liquids is formed by the aggregation of cationic tail groups. The electrostatic interactions between polar groups and the collective van der Waals interactions between nonpolar tail groups both contribute to the formation of tail domains, but the degrees of their contributions were unknown. In this work, by applying a strong external electric field to effectively overpower the electrostatic interactions between polar groups, we have determined that the tail aggregation is majorly attributed to the electrostatic interactions and the van der Waals interactions only have minor influence on the spatial heterogeneity phenomenon of ionic liquids.展开更多
Simultaneous generation of H_(2) fuel and value-added chemicals has attracted increasing attention since the photogenerated electrons and holes can be both employed to convert solar light into chemical energy.Herein,f...Simultaneous generation of H_(2) fuel and value-added chemicals has attracted increasing attention since the photogenerated electrons and holes can be both employed to convert solar light into chemical energy.Herein,for realizing UV-visible-NIR light driven dehydrogenation of benzyl alcohol(BA)into benzaldehydes(BAD)and H_(2),a novel localized surface plasmon resonance(LSPR)enhanced S-scheme heterojunction was designed by combining noble-metal-free plasmon MoO_(3-x) as oxidation semiconductor and Zn_(0.1)Cd_(0.9)S as reduction semiconductor.The photoredox system of Zn_(0.1)Cd_(0.9)S/MoO_(3-x) displayed an unconventional reaction model,in which the BA served as both electron donor and acceptor.The S-scheme charge transfer mechanism induced by the formed internal electric field enhanced the redox ability of charge carriers thermodynamically and boosted charge separation kinetically.Moreover,due to the LSPR effect of MoO_(3-x) nanosheets,Zn_(0.1)Cd_(0.9)S/MoO_(3-x) photocatalysts exhibited strong absorption in the region of full solar spectrum.Therefore,the Zn_(0.1)Cd_(0.9)S/MoO_(3-x) composite generated H_(2) and BAD simultaneously via selective oxidation of BA with high production(34.38 and 33.83 mmol×g^(–1) for H_(2) and BAD,respectively)upon full solar illumination.Even under NIR light irradiation,the H_(2) production rate could up to 94.5 mmol×g^(–1)×h^(–1).In addition,the Zn_(0.1)Cd_(0.9)S/MoO_(3-x) composite displayed effective photocatalytic H_(2) evolution rate up to 149.2 mmol×g^(–1)×h^(–1) from water,which was approximate 6 times that of pure Zn_(0.1)Cd_(0.9)S.This work provides a reference for rational design of plasmonic S-scheme heterojunction photocatalysts for coproduction of high-value chemicals and solar fuel production.展开更多
The authors aimed the study at examining macro- and trace elements content in elderly people of the 1 period of middle age (21-35) residing in Magadan town to assess the content of 25 trace elements in hair samples ...The authors aimed the study at examining macro- and trace elements content in elderly people of the 1 period of middle age (21-35) residing in Magadan town to assess the content of 25 trace elements in hair samples on individual and population levels by atom-emission spectrometry with inductively-bonded argon plasma. It turned out that the majority of surveyed subjects were characterized by deformation of element status demonstrated by excess and deficit of the basic essential elements of different degrees of manifestation. Deficit of Co (68% of surveyed people), Mg (67%), Ca (64%), Cu (47%), K (46%), Zn (44%), I (41%), Na (33%), P (27%) and Se (24%) was typical for female subjects as well as excess of Si (28%), Zn (22%) and P (20%). Male residents were characterized by deficit of Co (81%), Ca (66%), Mg (65%), I (50%), Cu (37%), K and Na (27%) and excess of Zn (41%). In individual cases it was noted excess concentration of nominally essential and toxic elements in both examined groups. They were: A1, As, Cd, Li, Ni, Pb, Sn, V and B. While analyzing of medians of chemical concentration it was stated reliable sex-related differences (P 〈 0.05): content of Ca, Mg and Mn was higher in hair samples of women, and content of As, B, Cd, Cr, K, Li, Na, P, Pb and V, on the contrary, was higher in male samples.展开更多
The oxidative dehydrogenation of isobutane to isobutene was examined for the use in the preparation of FSM-16 and related compounds doped by chromium with expectations that a yield of isobutene of greater than 8% coul...The oxidative dehydrogenation of isobutane to isobutene was examined for the use in the preparation of FSM-16 and related compounds doped by chromium with expectations that a yield of isobutene of greater than 8% could be achieved. The activity depended on the molding procedure of the catalyst and the doping method of the chromium species. In the present study, 8.8% and 8.3% of the yield of isobutene were obtained at 0.75 h and 6 h on-stream for the catalyst (Cr-loading; 6.2 wt.%) molded using wet treatment hut not pressurization treatment, in which the chromium species were directly added into the aqueous solution containing raw FSM-16 (hydrated sodium silicate powder) at an initial stage of the catalyst preparation. The structure information was based on XRD (X-ray diffraction), the specific surface area was determined using a conventional BET (Brunauer-Emmett-Teller) nitrogen adsorption and the loading of chromium was estimated using ICP (inductively coupled plasma). All those parameters combined with the molding method indicated that the catalytic activity was more influenced by the loading of chromium into bulk but not on surface of the catalyst rather than by the hexagonal structure of FSM-16 and the surface area.展开更多
Water-dispersed CdSe/Bi2Se3 core/shell QDs with a photothermal conversion coefficient of 27.09% have been synthesized by a cation exchange reaction. The microstructure and crystal structure of the QDs, which were conf...Water-dispersed CdSe/Bi2Se3 core/shell QDs with a photothermal conversion coefficient of 27.09% have been synthesized by a cation exchange reaction. The microstructure and crystal structure of the QDs, which were confirmed by TEM and XRD, showed that partial cation exchange occurred inside the CdSe QDs. Two main mechanisms are responsible for the excellent photothermal conversion: inhibition of radiative recombination of carriers due to the formation of type-II semiconductor heterostructures, and the large surface-to-volume ratio of the QDs. Photothermal conversion experiments indicated that the CdSe/Bi2Se3 QDs showed high photothermal conversion efficiency and excellent NIR photostability.展开更多
A series of triethylammonium-based chlorogallate(Ⅲ) ionic liquids with varied Lewis acidity was synthesized, characterized, and firstly applied to isobutane alkylation. The [Et3NHC1]-GaCl3 with XGaCl3 =0.65 display...A series of triethylammonium-based chlorogallate(Ⅲ) ionic liquids with varied Lewis acidity was synthesized, characterized, and firstly applied to isobutane alkylation. The [Et3NHC1]-GaCl3 with XGaCl3 =0.65 displayed a potential catalytic activity for the alkylation. The addition of copper halide into the chlorogallate(Ⅲ) ionic liquids dramatically enhanced the alkylation reac- tion. Up to 70.1% Cs selectivity and 91.3 RON were achieved with the [Et3NHC1]-GaC13-CuC1 (XGaCl3 = 0.65, CuCI = 5% tool) under 0.5 MPa, 900 r/min, 15 min, 288 K using the industrial C4 cut (isobutane/butene = 10). These results indicate that the chlorogallate(Ⅲ) system may be used as a promising catalyst for the C4 alkylation.展开更多
In this paper, we describe the synthesis of a novel copper ion hapten using the copper mercaptide of penicillenic acid (CMPA) derived from penicillin. Results from tests with immune rabbits indicate that: (i) A n...In this paper, we describe the synthesis of a novel copper ion hapten using the copper mercaptide of penicillenic acid (CMPA) derived from penicillin. Results from tests with immune rabbits indicate that: (i) A new antigen synthesized with CMPA has good stability and is safe for immunizing animals with no toxic phenomena being found in animal experiments; (ii) the immunogenic antigen (CMPA-BSA) can stimulate the immune system to produce specific antibodies with high titrations, up to 150000; and (iii) antibodies in antisera showed higher affinity to OVA-GSH-CuC1 than OVA-GSH, which indicates that the antibodies have specific affinity towards copper ions. These results confirm that the novel hapten and relevant antigen for copper ion have been successfully synthesized, giving progress towards an immunoassay for copper ions in environmental and food samples.展开更多
基金supported by the National Natural Science Foundation of China(21421001,21276116,21477050,21301076,21303074)Natural Science Foundation of Jiangsu Province(BK20140530,BK20150482)+5 种基金China Postdoctoral Science Foundation(2015M570409)Chinese-German Cooperation Research Project(GZ1091)Program for High-Level Innovative and Entrepreneurial Talents in Jiangsu ProvinceProgram for New Century Excellent Talents in University(NCET-13-0835)Henry Fok Education Foundation(141068)Six Talents Peak Project in Jiangsu Province(XCL-025)~~
文摘With the significant discharge of antibiotic wastewater into the aquatic and terrestrial ecosystems, antibiotic pollution has become a serious problem and presents a hazardous risk to the environment. To address such issues, various investigations on the removal of antibiotics have been undertaken. Photocatalysis has received tremendous attention owing to its great potential in removing antibiotics from aqueous solutions via a green, economic, and effective process. However, such a technology employing traditional photocatalysts suffers from major drawbacks such as light absorption being restricted to the UV spectrum only and fast charge recombination. To overcome these issues, considerable effort has been directed towards the development of advanced visible light-driven photocatalysts. This mini review summarises recent research progress in the state-of-the-art design and fabrication of photocatalysts with visible-light response for photocatalytic degradation of antibiotic wastewater. Such design strategies involve the doping of metal and non-metal into ultraviolet light-driven photocatalysts, development of new semiconductor photocatalysts, construction of heterojunction photocatalysts, and fabrication of surface plasmon resonance-enhanced photocatalytic systems. Additionally, some perspectives on the challenges and future developments in the area of photocatalytic degradation of antibiotics are provided.
基金Supported by the National Natural Science Foundation of China(21276163,21576168)
文摘The complicated reaction mechanism and the character of competitive reactions lead to a stringent requirement for the catalyst of C_4 alkylation process. Due to their unique properties, ionic liquids(ILs) are thought to be new potential acid catalysts for C_4 alkylation. An analysis of the regular and modified chloroaluminate ILs, novel Br?nsted ILs and composite ILs used in isobutane/butene alkylation shows that the use of either ILs or ILs coupled with mineral acid as homogeneous catalysts can help to greatly adjust the acid strength. By modifying the structural parameters of the cations and anions of the ILs, the solubility of the reactants could also be adjusted, which in turn displays a positive effect on improving the activity of ILs. Immobilization of ILs is an effective way to modulate the surface adsorption/desorption properties and acid strength distribution of the solid acid catalysts. Such a process has a tremendous potential to reduce the deactivation of catalyst and enhance the activity of the solid acid catalyst. The development of novel acid catalysts for C_4 alkylation is a comprehensive consideration of acid strength and its distribution, interfacial properties and transport characteristics.
基金supported by the National Key Projects for Fundamental Research and Development of China(2016YFB0600903)the National Natural Science Foundation of China(91434107,21506226,21476245)the Key Research Program of Frontier Sciences of Chinese Academy of Sciences(QYZDY-SSW-JSC011)~~
文摘A series of quaternary ammonium ionic liquids(ILs)were synthesized and employed as catalysts for the production of poly(isosorbide carbonate)(PIC)from diphenyl carbonate and isosorbide via a melt polycondensation process.The relationship between the anions of the ILs and the catalytic activities was investigated,and the readily‐prepared IL tetraethylammonium imidazolate(TEAI)was found to exhibit the highest catalytic activity.After optimizing the reaction conditions,a PIC with a weight‐average molecular weight(Mw)of25600g/mol was obtained,in conjunction with an isosorbide conversion of92%.As a means of modifying the molecular flexibility and thermal properties of the PIC,poly(aliphatic diol‐co‐isosorbide carbonate)s(PAIC)s were successfully synthesized,again using TEAI,and polymers with Mw values ranging from29000to112000g/mol were obtained.13C NMR analyses determined that the PAIC specimens had random microstructures,while differential scanning calorimetry demonstrated that each of the PAICs were amorphous and had glass transition temperatures ranging from50to115°C.Thermogravimetric analyses found Td‐5%values ranging from316to332°C for these polymers.Based on these data,it is evident that the incorporation of linear or cyclohexane‐based diol repeating units changed the thermal properties of the PIC.
文摘Electrochemical (EC) reactions play vital roles in many disciplines, and its molecular-level understanding is highly desired, in particular under reactions. The vibration spectroscopy is a powerful in situ technique for chemical analysis, yet its application to EC reactions is hindered by the strong attenuation of infrared (IR) light in both electrodes and electrolytes. Here we demonstrate that by incorporating appropriate sub-wavelength plasmonic structures at the metal electrode, the IR field at the EC interface can be greatly enhanced via the excitation of surface plasmon. This scheme facilitates in situ vibrational spectroscopic studies, especially using the surface-specific sum-frequency generation technique.
基金supported by the National Natural Science Foundation of China(21501016,21777011,51871037,51501024)the Innovative Research Team of Chongqing(CXTDG201602014)+1 种基金the Key Natural Science Foundation of Chongqing(cstc2017jcyjBX0052)the Plan for "National Youth Talents" of the Organization Department of the Central Committee~~
文摘Narrow-band BiOI photocatalysts usually suffer from low photocatalysis efficiency under visible light exposure because of rapid charge recombination. In this work, to overcome this deficiency of photosensitive BiOI, oxygen vacancies, Bi particles, and Bi2O2CO3 were co-induced in BiOI via a facile in situ assembly method at room temperature using NaBH4 as the reducing agent. In the synthesized ternary Bi/BiOI/(BiO)2CO3, the oxygen vacancies, dual heterojunctions (i.e., Bi/BiOI and Bi- OI/(BiO)2CO3), and surface plasmon resonance effect of the Bi particles contributed to efficient electron-hole separation and an increase in charge carrier concentration, thus boosting the overall visible light photocatalysis efficiency. The as-prepared catalysts were applied for the removal of NO in concentrations of parts per billion from air in continuous air flow under visible light illumination. Bi/BiOI/(BiO)2CO3 exhibited a highly enhanced NO removal ratio of 50.7%, much higher than that of the pristine BiOI (1.2%). Density functional theory calculations and experimental results revealed that the Bi/BiOI/(BiO)2CO3 composites promoted the production of reactive oxygen species for photocatalytic NO oxidation. Thus, this work provides a new strategy to modify narrow-band semiconductors and explore other bismuth-containing heterostructured visible-light-driven photocatalysts.
文摘In this work,a novel plasmon-assisted UV-vis-NIR-driven W_(18)O_(49)/Cd_(0.5)Zn_(0.5)S heterostructure photocatalyst was obtained by a facile ultrasonic-assisted electrostatic self-assembly strategy.The hybrid exhibits extraordinary H2 evolution activity of 147.7 mmol·g^(-1)·h^(-1) at room temperature due to the efficient charge separation and expanded light absorption.Our investigation shows that the unique Step-scheme(S-scheme)charge transfer and the‘hot electron’injection are both responsible for the extraordinary H2 evolution process,depending on the wavelength of the incident light.Moreover,by accelerating the surface reaction kinetics,the activity can be further elevated to 306.1 mmol·g^(-1)·h^(-1),accompanied by a high apparent quantum yield of 45.3% at 365±7.5 nm.This work provides us a potential strategy for the highly efficient conversion of the solar energy by elaborately combining a nonstoichiometric ratio plasmonic material with an appropriate active photocatalyst.
文摘The aromaticity of all possible substituted fullerene isomers of C18N2, C18B2, C18BN, and their molecular ions which originate from the C20 (Ih) cage were studied by the topological resonance energy (TRE) and the percentage topological resonance energy methods. The relationship between the aromaticity of C18BxNy isomers and the sites where the heteroatoms dope at the C20 (Ih) cage is discussed. Calculation results show that at the neutral and cationic states all the isomers are predicted to be antiaromatic with negative TREs, but their polyvalent anions are predicted to be aromatic with positive TREs. The most stable isomer is formed by heteroatom doping at the 1,11-sites in C18N2. C18B2, and C18BN. Heterofullerenes are more aromatic than C20. The stability order in the neutral states is C18N2〉C18BN〉C18B2〉C20. The stability order in closed-shell is C18B2^8- 〉C20^6- 〉C18BN^6- 〉C18N2^4-. This predicts theoretically that their polyvalent anions have high aromaticity.
文摘The cis and trans isomers separation of 2-butene-1,4-diol and lafutidine were studied by HPLC on two kinds of chiral columns: (S,S)-Whelk-O 1 and ChiraSpher. The isomers of 2-butene-1,4-diol can be separated on both chiral columns while the isomers of lafutidine can only be resolved on ChiraSpher column. The influence of different type and amount of mobile phase modifier on the isomers separation was extensively studied. The resolution of cis and trans isomers of 2-butene-1,4-diol was 2.61on (S,S)-Whelk-O 1 column with hexane-ethanol (97:3, v/v) as the mobile phase. The resolution of lafutidine was 1.89 on ChiraSpher column with hexane-ethanol-THF-diethylamine (92:3:5:0.1, v/v/v/v) as the mobile phase. LC-MS methods were developed to identify the isomer peaks.
基金Project(21176262) supported by the National Natural Science Foundation of ChinaProject(2010WK3029) supported by Science and Technology Program of Hunan Province,China
文摘Chiral ionic liquids (CILs) containing imidazolium cations and L-Proline (L-Pro) anions were applied as chiral selector to separate tryptophan (Trp) enantiomers on a C18 column by ligand exchange chromatography. Several factors influencing Trp enantiomers separation, such as alkyl chain length of CILs, concentrations of Cu2+ and CILs, pH of the mobile phase, flow rate, organic solvent and temperature, were studied. Under the optimal conditions, the Trp enantiomers could be successfully separated within 21 min with the resolution of 2.30. At the same time, some thermodynamical parameters were obtained. The experimental results show that the enthalpy values of the Trp enantiomers are negative, indicating that the separation process is exothermic. And the enthalpy values of D-Trp are larger than those of L-Trp, which indicates that L-Trp could form more stable ternary complexes with tryptophan enantiomers.
基金The project partially supported by National Natural Science Foundation of China under Grant No. 90403003 We thank Prof. Xiao-Qun Wang and Prof. Tao Li for useful discussions. Numerical computation of this work was carried out on the Parallel Computer Cluster of Insti- tute for Condensed Matter Physics (ICMP) at School of Physics, Peking University.
文摘In the present paper, we investigate the quantum phase transition in a spatially anisotropic antiferrornagnetic Heisenberg model of S =1 with single-ion energy anisotropy. By using the Schwinger boson representation, we calculate the Gaussian correction to the critical value J⊥^c caused by quantum spin fluctuations. We find that, for the positive single-ion energy, a nonzero value of J⊥^c is always needed to stabilize the antiferromagnetic long-range order in this model. It resolves a difference among literature and shows clearly that the effect of quantum fluctuations may qualitatively change a result obtained by the mean-field theories on lower-dimensional systems.
基金Supported by the Hundred Talent Program of the Chinese Academy of Sciencesthe General Program of the National Natural Science Foundation of China under Grant No. 10974208
文摘Nanoscale spatial heterogeneity in ionic liquids is formed by the aggregation of cationic tail groups. The electrostatic interactions between polar groups and the collective van der Waals interactions between nonpolar tail groups both contribute to the formation of tail domains, but the degrees of their contributions were unknown. In this work, by applying a strong external electric field to effectively overpower the electrostatic interactions between polar groups, we have determined that the tail aggregation is majorly attributed to the electrostatic interactions and the van der Waals interactions only have minor influence on the spatial heterogeneity phenomenon of ionic liquids.
文摘Simultaneous generation of H_(2) fuel and value-added chemicals has attracted increasing attention since the photogenerated electrons and holes can be both employed to convert solar light into chemical energy.Herein,for realizing UV-visible-NIR light driven dehydrogenation of benzyl alcohol(BA)into benzaldehydes(BAD)and H_(2),a novel localized surface plasmon resonance(LSPR)enhanced S-scheme heterojunction was designed by combining noble-metal-free plasmon MoO_(3-x) as oxidation semiconductor and Zn_(0.1)Cd_(0.9)S as reduction semiconductor.The photoredox system of Zn_(0.1)Cd_(0.9)S/MoO_(3-x) displayed an unconventional reaction model,in which the BA served as both electron donor and acceptor.The S-scheme charge transfer mechanism induced by the formed internal electric field enhanced the redox ability of charge carriers thermodynamically and boosted charge separation kinetically.Moreover,due to the LSPR effect of MoO_(3-x) nanosheets,Zn_(0.1)Cd_(0.9)S/MoO_(3-x) photocatalysts exhibited strong absorption in the region of full solar spectrum.Therefore,the Zn_(0.1)Cd_(0.9)S/MoO_(3-x) composite generated H_(2) and BAD simultaneously via selective oxidation of BA with high production(34.38 and 33.83 mmol×g^(–1) for H_(2) and BAD,respectively)upon full solar illumination.Even under NIR light irradiation,the H_(2) production rate could up to 94.5 mmol×g^(–1)×h^(–1).In addition,the Zn_(0.1)Cd_(0.9)S/MoO_(3-x) composite displayed effective photocatalytic H_(2) evolution rate up to 149.2 mmol×g^(–1)×h^(–1) from water,which was approximate 6 times that of pure Zn_(0.1)Cd_(0.9)S.This work provides a reference for rational design of plasmonic S-scheme heterojunction photocatalysts for coproduction of high-value chemicals and solar fuel production.
文摘The authors aimed the study at examining macro- and trace elements content in elderly people of the 1 period of middle age (21-35) residing in Magadan town to assess the content of 25 trace elements in hair samples on individual and population levels by atom-emission spectrometry with inductively-bonded argon plasma. It turned out that the majority of surveyed subjects were characterized by deformation of element status demonstrated by excess and deficit of the basic essential elements of different degrees of manifestation. Deficit of Co (68% of surveyed people), Mg (67%), Ca (64%), Cu (47%), K (46%), Zn (44%), I (41%), Na (33%), P (27%) and Se (24%) was typical for female subjects as well as excess of Si (28%), Zn (22%) and P (20%). Male residents were characterized by deficit of Co (81%), Ca (66%), Mg (65%), I (50%), Cu (37%), K and Na (27%) and excess of Zn (41%). In individual cases it was noted excess concentration of nominally essential and toxic elements in both examined groups. They were: A1, As, Cd, Li, Ni, Pb, Sn, V and B. While analyzing of medians of chemical concentration it was stated reliable sex-related differences (P 〈 0.05): content of Ca, Mg and Mn was higher in hair samples of women, and content of As, B, Cd, Cr, K, Li, Na, P, Pb and V, on the contrary, was higher in male samples.
文摘The oxidative dehydrogenation of isobutane to isobutene was examined for the use in the preparation of FSM-16 and related compounds doped by chromium with expectations that a yield of isobutene of greater than 8% could be achieved. The activity depended on the molding procedure of the catalyst and the doping method of the chromium species. In the present study, 8.8% and 8.3% of the yield of isobutene were obtained at 0.75 h and 6 h on-stream for the catalyst (Cr-loading; 6.2 wt.%) molded using wet treatment hut not pressurization treatment, in which the chromium species were directly added into the aqueous solution containing raw FSM-16 (hydrated sodium silicate powder) at an initial stage of the catalyst preparation. The structure information was based on XRD (X-ray diffraction), the specific surface area was determined using a conventional BET (Brunauer-Emmett-Teller) nitrogen adsorption and the loading of chromium was estimated using ICP (inductively coupled plasma). All those parameters combined with the molding method indicated that the catalytic activity was more influenced by the loading of chromium into bulk but not on surface of the catalyst rather than by the hexagonal structure of FSM-16 and the surface area.
基金This work has been partly supported by the National Basic Research Program of China (973 Program) No. 2011CB922204-2, and the National Natural Science Foundation of China (Nos. 11434010, 11147024, 11247025, 11304306, 11374002, and 61290303).
文摘Water-dispersed CdSe/Bi2Se3 core/shell QDs with a photothermal conversion coefficient of 27.09% have been synthesized by a cation exchange reaction. The microstructure and crystal structure of the QDs, which were confirmed by TEM and XRD, showed that partial cation exchange occurred inside the CdSe QDs. Two main mechanisms are responsible for the excellent photothermal conversion: inhibition of radiative recombination of carriers due to the formation of type-II semiconductor heterostructures, and the large surface-to-volume ratio of the QDs. Photothermal conversion experiments indicated that the CdSe/Bi2Se3 QDs showed high photothermal conversion efficiency and excellent NIR photostability.
基金the financial support from the Beijing Municipal Natural Science Foundation (2122052)Key Program of National Natural Science Foundation of China (21036007)National Basic Research Program of China (2009CB219904)
文摘A series of triethylammonium-based chlorogallate(Ⅲ) ionic liquids with varied Lewis acidity was synthesized, characterized, and firstly applied to isobutane alkylation. The [Et3NHC1]-GaCl3 with XGaCl3 =0.65 displayed a potential catalytic activity for the alkylation. The addition of copper halide into the chlorogallate(Ⅲ) ionic liquids dramatically enhanced the alkylation reac- tion. Up to 70.1% Cs selectivity and 91.3 RON were achieved with the [Et3NHC1]-GaC13-CuC1 (XGaCl3 = 0.65, CuCI = 5% tool) under 0.5 MPa, 900 r/min, 15 min, 288 K using the industrial C4 cut (isobutane/butene = 10). These results indicate that the chlorogallate(Ⅲ) system may be used as a promising catalyst for the C4 alkylation.
基金supported by the National Natural Science Foundation of China (Grant No. 30821005)National High Technology Research and Development Program of China (Grant No. 2007AA10Z401)
文摘In this paper, we describe the synthesis of a novel copper ion hapten using the copper mercaptide of penicillenic acid (CMPA) derived from penicillin. Results from tests with immune rabbits indicate that: (i) A new antigen synthesized with CMPA has good stability and is safe for immunizing animals with no toxic phenomena being found in animal experiments; (ii) the immunogenic antigen (CMPA-BSA) can stimulate the immune system to produce specific antibodies with high titrations, up to 150000; and (iii) antibodies in antisera showed higher affinity to OVA-GSH-CuC1 than OVA-GSH, which indicates that the antibodies have specific affinity towards copper ions. These results confirm that the novel hapten and relevant antigen for copper ion have been successfully synthesized, giving progress towards an immunoassay for copper ions in environmental and food samples.