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2021 Volume 37 Issue 6
2021, 37(6): 961-967
doi: 10.11862/CJIC.2021.130
Abstract:
We successfully synthesized (X-EtHDabco)[ZnBr4] (X=H, F, Cl for compound 1, 2, and 3, EtDabco=N-ethyl-1, 4-diazoniabicyclo[2.2.2]octane) through precise molecular design. Systematic measurements (powder X-ray diffraction, differential scanning calorimetry measurements, dielectric measurements) were performed on these compounds. It is noteworthy that, no hint of heat anomaly was observed for 1, while both 2 and 3 displayed intriguing isostructural order-disorder phase transition near 230 K. Through the analysis of the crystal structure, the order-disorder transformation of organic ammonium plays a major role in the phase transition, in addition, the displacement of the inorganic framework also contributes to dielectric response.
We successfully synthesized (X-EtHDabco)[ZnBr4] (X=H, F, Cl for compound 1, 2, and 3, EtDabco=N-ethyl-1, 4-diazoniabicyclo[2.2.2]octane) through precise molecular design. Systematic measurements (powder X-ray diffraction, differential scanning calorimetry measurements, dielectric measurements) were performed on these compounds. It is noteworthy that, no hint of heat anomaly was observed for 1, while both 2 and 3 displayed intriguing isostructural order-disorder phase transition near 230 K. Through the analysis of the crystal structure, the order-disorder transformation of organic ammonium plays a major role in the phase transition, in addition, the displacement of the inorganic framework also contributes to dielectric response.
2021, 37(6): 968-976
doi: 10.11862/CJIC.2021.123
Abstract:
SrZrO3: Ce nanoparticles were prepared by reverse coprecipitation method with different precipitants. The phase, morphology, luminescence intensity and sintering densification of the samples were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetry-differential thermal analysis (TG-DTA). The thermal analysis kinetics of different precursors were discussed. The results showed that the prismatic and nearly spherical SrZrO3: Ce particles with good dispersion were obtained by calcining the precursors prepared with single phase and multiphase precipitants at 1 000℃ for 2 h, with the particle sizes of about 80 and 60 nm, respectively. Using Doyle Ozawa integral method and Kissinger differential method, the average apparent activation energies in different reaction stages of precursors prepared with single phase and multiphase precipitants were 94.18, 69.39, 255.72 kJ·mol-1 and 90.46, 51.03, 232.35 kJ·mol-1, respectively. The activation energies of crystal growth: Esingle phase=27.97 kJ·mol-1 and Emultiphase=22.53 kJ·mol-1, respectively. The apparent activation energy and grain growth activation energy of the latter were lower than those of the former, which indicates that the sample prepared with multiphase precipitant reduces the synthesis energy and improves the particle activity, and its luminous intensity was obviously better than that of the sample prepared with single phase precipitant. After vacuum sintering at 1 760℃ for 4 h, the sample prepared with multiphase precipitant had uniform grain size and achieved densification.
SrZrO3: Ce nanoparticles were prepared by reverse coprecipitation method with different precipitants. The phase, morphology, luminescence intensity and sintering densification of the samples were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetry-differential thermal analysis (TG-DTA). The thermal analysis kinetics of different precursors were discussed. The results showed that the prismatic and nearly spherical SrZrO3: Ce particles with good dispersion were obtained by calcining the precursors prepared with single phase and multiphase precipitants at 1 000℃ for 2 h, with the particle sizes of about 80 and 60 nm, respectively. Using Doyle Ozawa integral method and Kissinger differential method, the average apparent activation energies in different reaction stages of precursors prepared with single phase and multiphase precipitants were 94.18, 69.39, 255.72 kJ·mol-1 and 90.46, 51.03, 232.35 kJ·mol-1, respectively. The activation energies of crystal growth: Esingle phase=27.97 kJ·mol-1 and Emultiphase=22.53 kJ·mol-1, respectively. The apparent activation energy and grain growth activation energy of the latter were lower than those of the former, which indicates that the sample prepared with multiphase precipitant reduces the synthesis energy and improves the particle activity, and its luminous intensity was obviously better than that of the sample prepared with single phase precipitant. After vacuum sintering at 1 760℃ for 4 h, the sample prepared with multiphase precipitant had uniform grain size and achieved densification.
2021, 37(6): 977-983
doi: 10.11862/CJIC.2021.128
Abstract:
A kind of carbon spheres decorated carbon nitride (C/g-C3N4) composite photocatalysts were successfully synthesized by hydrothermal method using glucose and g-C3N4 as raw materials. The structure, composition, morphology, specific surface area and optical properties of these photocatalysts were fully characterized by X-ray powder diffraction, scanning electron microscope, N2 adsorption-desorption, ultraviolet-visible diffuse reflectance spectroscopy, surface photovoltage spectroscopy and electron paramagnetic resonance. The results showed that the carbon spheres with a diameter of about 20 nm were tightly present on the surface of g-C3N4. When the dosage ratio of glucose to g-C3N4 (mass fraction) was 1%, the composite photocatalyst was the best catalyst. Compared with g-C3N4, the specific surface area of g-C3N4 with 1% C (1% C/g-C3N4) was significantly increased, the visible light response range was expanded, and the separation efficiency of photogenerated electrons and holes of the catalyst was also improved. In addition, under the irradiation of a 400 W metal halide lamp with 420 nm filter, 87% of rhodamine B (10 μmol·L-1) could be fully degraded by 1% C/g-C3N4 composite photocatalyst within 80 min. The efficiency of this catalyst was three times that of pure g-C3N4 under the same conditions and its stability was also good.
A kind of carbon spheres decorated carbon nitride (C/g-C3N4) composite photocatalysts were successfully synthesized by hydrothermal method using glucose and g-C3N4 as raw materials. The structure, composition, morphology, specific surface area and optical properties of these photocatalysts were fully characterized by X-ray powder diffraction, scanning electron microscope, N2 adsorption-desorption, ultraviolet-visible diffuse reflectance spectroscopy, surface photovoltage spectroscopy and electron paramagnetic resonance. The results showed that the carbon spheres with a diameter of about 20 nm were tightly present on the surface of g-C3N4. When the dosage ratio of glucose to g-C3N4 (mass fraction) was 1%, the composite photocatalyst was the best catalyst. Compared with g-C3N4, the specific surface area of g-C3N4 with 1% C (1% C/g-C3N4) was significantly increased, the visible light response range was expanded, and the separation efficiency of photogenerated electrons and holes of the catalyst was also improved. In addition, under the irradiation of a 400 W metal halide lamp with 420 nm filter, 87% of rhodamine B (10 μmol·L-1) could be fully degraded by 1% C/g-C3N4 composite photocatalyst within 80 min. The efficiency of this catalyst was three times that of pure g-C3N4 under the same conditions and its stability was also good.
2021, 37(6): 984-988
doi: 10.11862/CJIC.2021.131
Abstract:
Er3+-doped novel bismuthate (Li2O-SrO-ZnO-Bi2O3, LSZB) glasses have been fabricated through the conventional melt-quenching method, and the spectroscopic properties of Er3+ in the glasses were characterized. The density, refractive indexes, Raman spectra, optical absorption spectra, fluorescence spectra and radiative lifetime of the glasses were measured and analyzed. The fluorescence properties were calculated by using the Judd-Ofelt theory. The emission peak from the Er3+: 4I13/2→4I15/2 transition located around 1.53 μm with a full width at half maximum (FWHM) of ~78 nm. The lifetime of the 4I13/2 level was 2.848 ms and the quantum efficiency was 99.93%, respectively. The emission cross section was estimated to be 9.76×10-21 cm2. In summary, the above results indicate that Er3+-doped LSZB glasses have good spectral characteristics.
Er3+-doped novel bismuthate (Li2O-SrO-ZnO-Bi2O3, LSZB) glasses have been fabricated through the conventional melt-quenching method, and the spectroscopic properties of Er3+ in the glasses were characterized. The density, refractive indexes, Raman spectra, optical absorption spectra, fluorescence spectra and radiative lifetime of the glasses were measured and analyzed. The fluorescence properties were calculated by using the Judd-Ofelt theory. The emission peak from the Er3+: 4I13/2→4I15/2 transition located around 1.53 μm with a full width at half maximum (FWHM) of ~78 nm. The lifetime of the 4I13/2 level was 2.848 ms and the quantum efficiency was 99.93%, respectively. The emission cross section was estimated to be 9.76×10-21 cm2. In summary, the above results indicate that Er3+-doped LSZB glasses have good spectral characteristics.
2021, 37(6): 989-994
doi: 10.11862/CJIC.2021.134
Abstract:
Three complexes {[Cu2(L)4]·CHCl3}n (1), {[Zn(L)2]·4CHCl3}n (2) and {[Mn(L)2]·4CHCl3}n (3) were synthesized from the reaction of 3-((5-(pyridin-3-yl)-1, 3, 4-oxadiazol-2-yl)thio)pentane-2, 4-dione (HL) with Cu(OAc)2·H2O, Zn(OAc)2·2H2O and Mn(OAc)2·4H2O, and characterized by elemental analysis, infrared spectroscopy, powder X-ray diffraction and single-crystal X-ray diffraction. In the solid state, coordination polymer 1 forms 1D helical chain structure, and coordination polymer 2 and 3 form 2D network structure.
Three complexes {[Cu2(L)4]·CHCl3}n (1), {[Zn(L)2]·4CHCl3}n (2) and {[Mn(L)2]·4CHCl3}n (3) were synthesized from the reaction of 3-((5-(pyridin-3-yl)-1, 3, 4-oxadiazol-2-yl)thio)pentane-2, 4-dione (HL) with Cu(OAc)2·H2O, Zn(OAc)2·2H2O and Mn(OAc)2·4H2O, and characterized by elemental analysis, infrared spectroscopy, powder X-ray diffraction and single-crystal X-ray diffraction. In the solid state, coordination polymer 1 forms 1D helical chain structure, and coordination polymer 2 and 3 form 2D network structure.
2021, 37(6): 995-1003
doi: 10.11862/CJIC.2021.107
Abstract:
Herein, fluorescent carbon dots (CDs) were synthesized through a hydrothermal method using poly (allylamine hydrochloride) as reaction substrate. After introduce of potassium permanganate, CDs-MnO2 nanocomposite were prepared through an in situ redox reaction. The as-prepared nanomaterials were characterized by transmission electron microscope, X-ray photoelectron spectroscopy, nanometer size analysis, ultraviolet-visible absorption spectrum, fluorescence spectrum, and fluorescence lifetime. It was demonstrated that the MnO2 quenched the fluorescence intensity of CDs through static quenching effect (SQE) and inner filter effect (IFE). Further, taking advantage of active thiol in its molecule, tiopronin (TPN) decomposed MnO2 through a unique redox reaction, which made the quencher disappeared and thus restored the fluorescence. Therefore, a CDs-MnO2 nanocomposite based fluorescent sensor was established to detect tiopronin. This method showed good sensitivity and selectivity for TPN. The linear range was 0.2~80 μmol·L-1 with a detection limit of 0.11 μmol·L-1. The MnO2 nanomaterials mediated fluorescence method was applied for the TPN detection in urine sample and the recovery was in the range of 97.57%~102.58%.
Herein, fluorescent carbon dots (CDs) were synthesized through a hydrothermal method using poly (allylamine hydrochloride) as reaction substrate. After introduce of potassium permanganate, CDs-MnO2 nanocomposite were prepared through an in situ redox reaction. The as-prepared nanomaterials were characterized by transmission electron microscope, X-ray photoelectron spectroscopy, nanometer size analysis, ultraviolet-visible absorption spectrum, fluorescence spectrum, and fluorescence lifetime. It was demonstrated that the MnO2 quenched the fluorescence intensity of CDs through static quenching effect (SQE) and inner filter effect (IFE). Further, taking advantage of active thiol in its molecule, tiopronin (TPN) decomposed MnO2 through a unique redox reaction, which made the quencher disappeared and thus restored the fluorescence. Therefore, a CDs-MnO2 nanocomposite based fluorescent sensor was established to detect tiopronin. This method showed good sensitivity and selectivity for TPN. The linear range was 0.2~80 μmol·L-1 with a detection limit of 0.11 μmol·L-1. The MnO2 nanomaterials mediated fluorescence method was applied for the TPN detection in urine sample and the recovery was in the range of 97.57%~102.58%.
2021, 37(6): 1004-1016
doi: 10.11862/CJIC.2021.129
Abstract:
A series of KIT-6 were synthesized by hydrothermal method at varied aging temperatures (80, 100, 120 and 150℃), which were used as supports to fabricate CeO2/KIT-6 catalysts. Combined with X-ray diffraction, N2-physisorption, temperature-programmed desorption of NH3 and CO2, transmission electron microscopy, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy results, the effect of aging temperatures on the structure of KIT-6 and the catalytic activity of CeO2/KIT-6 for direct synthesis of dimethyl carbonate (DMC) from CO2 and methanol were investigated in detail. The results indicated that the KIT-6 synthesized at different aging temperatures maintained their unique three-dimensional pore structure. With the increasing aging temperature, the surface areas of KIT-6 firstly increased and then decreased, which attained the maximum (683 m2·g-1) as the aging temperature was 100℃. High surface areas of KIT-6 favor for the dispersion of CeO2 and thus improve the number of exposed active sites. The catalytic activity increases with the improved number of the medium base/acid adsorption sites and content of Ce3+. Herein, the particle size of CeO2 for CeO2/100-KIT-6 was the smallest (5.9 nm) and therefore the number of exposed active sites reached the maximum, which contributed to the optimal catalytic activity. Moreover, the effect of reaction temperature and pressure on the catalytic activity of CeO2/100-KIT-6 were studied. The results showed that the catalytic activity firstly increased and then decreased with the increasing reaction temperature, and attained the highest as the reaction temperature was 140℃. In addition, the catalytic activity increased with the increase of reaction pressure. Furthermore, the recycle stability of CeO2/100-KIT-6 was also studied under 140℃ and 6.8 MPa. The results showed that the DMC yield decreased from 15 mmol·gCeO2-1 to 2.8 mmol·gCeO2-1 after recycle six times, which is due to the decrease of active sites resulting from the agglomeration of CeO2 nanoparticles.
A series of KIT-6 were synthesized by hydrothermal method at varied aging temperatures (80, 100, 120 and 150℃), which were used as supports to fabricate CeO2/KIT-6 catalysts. Combined with X-ray diffraction, N2-physisorption, temperature-programmed desorption of NH3 and CO2, transmission electron microscopy, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy results, the effect of aging temperatures on the structure of KIT-6 and the catalytic activity of CeO2/KIT-6 for direct synthesis of dimethyl carbonate (DMC) from CO2 and methanol were investigated in detail. The results indicated that the KIT-6 synthesized at different aging temperatures maintained their unique three-dimensional pore structure. With the increasing aging temperature, the surface areas of KIT-6 firstly increased and then decreased, which attained the maximum (683 m2·g-1) as the aging temperature was 100℃. High surface areas of KIT-6 favor for the dispersion of CeO2 and thus improve the number of exposed active sites. The catalytic activity increases with the improved number of the medium base/acid adsorption sites and content of Ce3+. Herein, the particle size of CeO2 for CeO2/100-KIT-6 was the smallest (5.9 nm) and therefore the number of exposed active sites reached the maximum, which contributed to the optimal catalytic activity. Moreover, the effect of reaction temperature and pressure on the catalytic activity of CeO2/100-KIT-6 were studied. The results showed that the catalytic activity firstly increased and then decreased with the increasing reaction temperature, and attained the highest as the reaction temperature was 140℃. In addition, the catalytic activity increased with the increase of reaction pressure. Furthermore, the recycle stability of CeO2/100-KIT-6 was also studied under 140℃ and 6.8 MPa. The results showed that the DMC yield decreased from 15 mmol·gCeO2-1 to 2.8 mmol·gCeO2-1 after recycle six times, which is due to the decrease of active sites resulting from the agglomeration of CeO2 nanoparticles.
2021, 37(6): 1017-1026
doi: 10.11862/CJIC.2021.118
Abstract:
Herein, nitrogen-doped carbon nanonets (NCNs) were successfully prepared through one-step carbonization/activation method by using phenanthrene as carbon source and NH3 as nitrogen source. The sample obtained at 800℃ (NCN800) possessed a unique network structure, large specific surface area (1 567 m2·g-1) and high atomic fraction of N (4.41%) and O (13.71%) elements. Thanks to these structural features, NCN800 exhibited high specific capacitance (542.3 F·g-1 at 0.05 A·g-1) in a three-electrode system as a working electrode. In addition, NCN800 electrode for symmetric supercapacitor exhibited high specific capacitance (443.6 F·g-1 at 0.05 A·g-1), good rate capability (341.2 F·g-1 at 20 A·g-1) and outstanding cycling stability (93.5% capacitance retention after 30 000 cycles).
Herein, nitrogen-doped carbon nanonets (NCNs) were successfully prepared through one-step carbonization/activation method by using phenanthrene as carbon source and NH3 as nitrogen source. The sample obtained at 800℃ (NCN800) possessed a unique network structure, large specific surface area (1 567 m2·g-1) and high atomic fraction of N (4.41%) and O (13.71%) elements. Thanks to these structural features, NCN800 exhibited high specific capacitance (542.3 F·g-1 at 0.05 A·g-1) in a three-electrode system as a working electrode. In addition, NCN800 electrode for symmetric supercapacitor exhibited high specific capacitance (443.6 F·g-1 at 0.05 A·g-1), good rate capability (341.2 F·g-1 at 20 A·g-1) and outstanding cycling stability (93.5% capacitance retention after 30 000 cycles).
2021, 37(6): 1027-1036
doi: 10.11862/CJIC.2021.115
Abstract:
Tm3+-Tb3+-Eu3+ co-doped fluorescence glass ceramics containing Na3Gd(PO4)2 crystals were synthesized by melt crystallization method and luminescence properties were studied. The crystal structure and optimum heat treatment conditions (740℃/3 h) were determined by differential scanning calorimetry (DSC), X-ray diffraction (XRD) and scanning electron microscope (SEM). Under the excitation of 359 nm, when the doping concentrations (molar fraction) of Tm2O3, Tb4O7 and Eu2O3 were 0.2%, 0.2% and 0.95%, respectively, the chromaticity coordinates of glass ceramics were (0.333 2, 0.318 8) close to the standard white light (0.333, 0.333). Combined with fluorescence spectra and fluorescence decay curve analysis, the energy transfer of Tm3+→Eu3+, Tb3+→Eu3+ in the sample was confirmed.
Tm3+-Tb3+-Eu3+ co-doped fluorescence glass ceramics containing Na3Gd(PO4)2 crystals were synthesized by melt crystallization method and luminescence properties were studied. The crystal structure and optimum heat treatment conditions (740℃/3 h) were determined by differential scanning calorimetry (DSC), X-ray diffraction (XRD) and scanning electron microscope (SEM). Under the excitation of 359 nm, when the doping concentrations (molar fraction) of Tm2O3, Tb4O7 and Eu2O3 were 0.2%, 0.2% and 0.95%, respectively, the chromaticity coordinates of glass ceramics were (0.333 2, 0.318 8) close to the standard white light (0.333, 0.333). Combined with fluorescence spectra and fluorescence decay curve analysis, the energy transfer of Tm3+→Eu3+, Tb3+→Eu3+ in the sample was confirmed.
2021, 37(6): 1037-1045
doi: 10.11862/CJIC.2021.116
Abstract:
Fe-based Prussian blue material (FePB) was synthesized by coprecipitation method at room temperature using sodium citrate as chelating agent. A high yield of 500 g per preparation can be obtained by using a 20 L reactor and a Na4Fe(CN)6 precursor with a concentration up to 0.5 mol·L-1. The results of electrochemical measurements indicate that the obtained FePB showed a high capacity, excellent rate capability and long cycle life. At 0.1C, the first discharge capacity of FePB reached 117 mAh·g-1. At a current density as high as 10C, the FePB can still yield a discharge capacity of 92 mAh·g-1. After 500 cycles at 1C, a specific capacity of 87 mAh·g-1 still maintained with a retention of 89%. Pouch-type Na-ion full battery was fabricated using commercial hard carbon as anode and FePB as cathode, which exhibited a capacity retention of 75% after 400 cycles at 50 mA. The excellent electrochemical performance of the FePB is attributed to its high sodium content, low defect, border-rich microstructure and the unique open framework structure of the Prussian blue analogues.
Fe-based Prussian blue material (FePB) was synthesized by coprecipitation method at room temperature using sodium citrate as chelating agent. A high yield of 500 g per preparation can be obtained by using a 20 L reactor and a Na4Fe(CN)6 precursor with a concentration up to 0.5 mol·L-1. The results of electrochemical measurements indicate that the obtained FePB showed a high capacity, excellent rate capability and long cycle life. At 0.1C, the first discharge capacity of FePB reached 117 mAh·g-1. At a current density as high as 10C, the FePB can still yield a discharge capacity of 92 mAh·g-1. After 500 cycles at 1C, a specific capacity of 87 mAh·g-1 still maintained with a retention of 89%. Pouch-type Na-ion full battery was fabricated using commercial hard carbon as anode and FePB as cathode, which exhibited a capacity retention of 75% after 400 cycles at 50 mA. The excellent electrochemical performance of the FePB is attributed to its high sodium content, low defect, border-rich microstructure and the unique open framework structure of the Prussian blue analogues.
2021, 37(6): 1046-1054
doi: 10.11862/CJIC.2021.120
Abstract:
The cathode material LiNi0.8Co0.1Mn0.1O2 for lithium ion battery was doped by F using a high temperature solid state method with lithium fluoride. The microscopic mechanism of F affecting the structure and performance of LiNi0.8Co0.1Mn0.1O2 was investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS) and electrochemical measurements. The results show that appropriate dosage of F can increase the specific discharge capacity, rate capability, cycle performance and thermal stability of the cathode material. The optimum comprehensive performance of the material can be obtained at F molar fraction of 1.5%, the initial discharge specific capacity (0.2C) and capacity retention rate after 50 cycles (1C) were increased from the original 174.0 mAh·g-1 (78.7%) to 178.6 mAh·g-1 (85.7%), respectively. The improvement performance of the LiNi0.8Co0.1Mn0.1O2 cathode material by F doping can be attributed to the ability of F to enhance the bonding between the transition metal, lithium and oxygen layers, which improves the structural stability of the material. In addition, F-doping is beneficial to decrease the interface impedance and charge transfer impedance during the electrochemical reaction.
The cathode material LiNi0.8Co0.1Mn0.1O2 for lithium ion battery was doped by F using a high temperature solid state method with lithium fluoride. The microscopic mechanism of F affecting the structure and performance of LiNi0.8Co0.1Mn0.1O2 was investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS) and electrochemical measurements. The results show that appropriate dosage of F can increase the specific discharge capacity, rate capability, cycle performance and thermal stability of the cathode material. The optimum comprehensive performance of the material can be obtained at F molar fraction of 1.5%, the initial discharge specific capacity (0.2C) and capacity retention rate after 50 cycles (1C) were increased from the original 174.0 mAh·g-1 (78.7%) to 178.6 mAh·g-1 (85.7%), respectively. The improvement performance of the LiNi0.8Co0.1Mn0.1O2 cathode material by F doping can be attributed to the ability of F to enhance the bonding between the transition metal, lithium and oxygen layers, which improves the structural stability of the material. In addition, F-doping is beneficial to decrease the interface impedance and charge transfer impedance during the electrochemical reaction.
2021, 37(6): 1055-1061
doi: 10.11862/CJIC.2021.122
Abstract:
In order to solve the high cost of fuel cell Pt-based catalysts, nitrogen-doped carbon non-noble metal oxygen reduction reaction (ORR) catalysts have been widely studied. The amorphous Zn(Ⅱ)-organic framework was prepared by solvothermal method and the Zn/N co-doped carbon catalyst was obtained by thermally processing. The results showed that the ZnN/C-900 catalyst (pyrolyzed at 900℃) had a uniform spherical structure. The N2 adsorption-desorption isotherms of ZnN/C-900 catalyst showed that it had a specific surface area of up to 961 m2 g-1, and the atomic percentages of active N and Zn were 1.6% and 5.87%. The catalyst had high ORR catalytic activity and stability. In alkaline medium, the initial potential, half-wave potential and limiting current density of ZnN/C-900 were 0.955 V, 0.855 V and 7.10 mA·cm-2, respectively. In acid medium, the initial potential, half-wave potential and limiting current density of ZnN/C-900 were 0.882 V, 0.649 V and 6.01 mA·cm-2, respectively. ZnN/C-900 exhibited high stability and resistance to methanol poisoning.
In order to solve the high cost of fuel cell Pt-based catalysts, nitrogen-doped carbon non-noble metal oxygen reduction reaction (ORR) catalysts have been widely studied. The amorphous Zn(Ⅱ)-organic framework was prepared by solvothermal method and the Zn/N co-doped carbon catalyst was obtained by thermally processing. The results showed that the ZnN/C-900 catalyst (pyrolyzed at 900℃) had a uniform spherical structure. The N2 adsorption-desorption isotherms of ZnN/C-900 catalyst showed that it had a specific surface area of up to 961 m2 g-1, and the atomic percentages of active N and Zn were 1.6% and 5.87%. The catalyst had high ORR catalytic activity and stability. In alkaline medium, the initial potential, half-wave potential and limiting current density of ZnN/C-900 were 0.955 V, 0.855 V and 7.10 mA·cm-2, respectively. In acid medium, the initial potential, half-wave potential and limiting current density of ZnN/C-900 were 0.882 V, 0.649 V and 6.01 mA·cm-2, respectively. ZnN/C-900 exhibited high stability and resistance to methanol poisoning.
2021, 37(6): 1062-1070
doi: 10.11862/CJIC.2021.138
Abstract:
Herein, nanoflower-like nickel-cobalt phosphates coated on nickel foam (NiCoP/NF) were synthesized by two steps of hydrothermal and low temperature phosphating reaction without precipitator. The result showed that when the molar ratio of Ni and Co was 1:1, the Ni1/2Co1/2P/NF electrode delivered a high specific capacitance which can reach 1 276.36 F·g-1 at the current density of 1 A·g-1. 78.23% of initial specific capacitance was maintained after 3 000 charging and discharging cycles at the current density of 10 A·g-1. What's more, an asymmetric supercapacitor (Ni1/2Co1/2P/NF//AC/NF) was assembled using Ni1/2Co1/2P/NF and activated carbon (AC) as positive and negative electrodes. The device delivered a high energy density of 36.25 Wh·kg-1 at a power density of 725 W·kg-1.
Herein, nanoflower-like nickel-cobalt phosphates coated on nickel foam (NiCoP/NF) were synthesized by two steps of hydrothermal and low temperature phosphating reaction without precipitator. The result showed that when the molar ratio of Ni and Co was 1:1, the Ni1/2Co1/2P/NF electrode delivered a high specific capacitance which can reach 1 276.36 F·g-1 at the current density of 1 A·g-1. 78.23% of initial specific capacitance was maintained after 3 000 charging and discharging cycles at the current density of 10 A·g-1. What's more, an asymmetric supercapacitor (Ni1/2Co1/2P/NF//AC/NF) was assembled using Ni1/2Co1/2P/NF and activated carbon (AC) as positive and negative electrodes. The device delivered a high energy density of 36.25 Wh·kg-1 at a power density of 725 W·kg-1.
Design, Synthesis and Fluorescence Imaging Application of Hypochlorite Probe Based on Coumarin-oxime
2021, 37(6): 1071-1079
doi: 10.11862/CJIC.2021.133
Abstract:
We designed and synthesized a fluorescent probe for hypochlorite based on coumarin-oxime (Cou-HC). Not only Cou-HC showed a rapid and highly selective response to hypochlorite, but also the product after the probe oxidation did not react with biological thiols, which could avoid the interference of biological thiols on the response of hypochlorite. The results of cell imaging experiments showed that the probe could perform real-time imaging of endogenous and exogenous hypochlorite in RAW 264.7 cells, which proves the probe's ability to detect hypochlorite in living systems.
We designed and synthesized a fluorescent probe for hypochlorite based on coumarin-oxime (Cou-HC). Not only Cou-HC showed a rapid and highly selective response to hypochlorite, but also the product after the probe oxidation did not react with biological thiols, which could avoid the interference of biological thiols on the response of hypochlorite. The results of cell imaging experiments showed that the probe could perform real-time imaging of endogenous and exogenous hypochlorite in RAW 264.7 cells, which proves the probe's ability to detect hypochlorite in living systems.
2021, 37(6): 1080-1088
doi: 10.11862/CJIC.2021.117
Abstract:
The magnetic Fe3O4-supported Schiff base adsorption material was synthesized via the reaction with activated silica gel silane and salicylaldehyde or its derivatives by homogeneous method and heterogeneous method, respectively. The prepared materials were fully characterized by infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and so on. The adsorption performance of these materials on Cu(Ⅱ), Pb (Ⅱ) and Cd(Ⅱ) in water was studied at 30℃. The effects of synthesis method, pH value, ion concentration and material structures on the adsorption properties were examined. Finally, the regeneration property of the adsorbent was evaluated. The results showed that the obtained materials exhibited good adsorption performance for Cu (Ⅱ), Pb(Ⅱ) and Cd(Ⅱ) ions, and the adsorption capacity increased with the increase of pH value in the range of 1~6. The adsorption capacity of the adsorbents obtained by heterogeneous method was better than those of homogeneous method. In addition, the materials bearing electron-donating groups on the Schiff base showed better adsorption properties. This type of adsorbent exhibited good regeneration property with 89.4% regeneration rate after 4 cycles.
The magnetic Fe3O4-supported Schiff base adsorption material was synthesized via the reaction with activated silica gel silane and salicylaldehyde or its derivatives by homogeneous method and heterogeneous method, respectively. The prepared materials were fully characterized by infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and so on. The adsorption performance of these materials on Cu(Ⅱ), Pb (Ⅱ) and Cd(Ⅱ) in water was studied at 30℃. The effects of synthesis method, pH value, ion concentration and material structures on the adsorption properties were examined. Finally, the regeneration property of the adsorbent was evaluated. The results showed that the obtained materials exhibited good adsorption performance for Cu (Ⅱ), Pb(Ⅱ) and Cd(Ⅱ) ions, and the adsorption capacity increased with the increase of pH value in the range of 1~6. The adsorption capacity of the adsorbents obtained by heterogeneous method was better than those of homogeneous method. In addition, the materials bearing electron-donating groups on the Schiff base showed better adsorption properties. This type of adsorbent exhibited good regeneration property with 89.4% regeneration rate after 4 cycles.
2021, 37(6): 1089-1096
doi: 10.11862/CJIC.2021.127
Abstract:
A fluorescent probe 1, based on boron fluoride dipyrrole (BODIPY) chromophore containing phenyl picolinate as a recognition moiety, was designed, synthesized, and characterized by 1H NMR, 13C NMR, HRMS and X-ray diffraction. Probe 1 had a high fluorescence quantum yield (0.79), and could selectively and sensitively recognize Cu2+ from other cations by a fluorescence quenching method. The limit of detection of probe 1 was 0.15 μmol·L-1. In addition, the recognition mechanism of the fluorescent response to copper ions was verified by HRMS in this work.
A fluorescent probe 1, based on boron fluoride dipyrrole (BODIPY) chromophore containing phenyl picolinate as a recognition moiety, was designed, synthesized, and characterized by 1H NMR, 13C NMR, HRMS and X-ray diffraction. Probe 1 had a high fluorescence quantum yield (0.79), and could selectively and sensitively recognize Cu2+ from other cations by a fluorescence quenching method. The limit of detection of probe 1 was 0.15 μmol·L-1. In addition, the recognition mechanism of the fluorescent response to copper ions was verified by HRMS in this work.
2021, 37(6): 1097-1105
doi: 10.11862/CJIC.2021.142
Abstract:
The hydrogen storage properties of Mg(NH2)2-2LiH system were significantly enhanced by adding a small amount of potassium tert-butoxide (C4H9OK). The 0.08 mol C4H9OK-added sample (Mg(NH2)2-2LiH-0.08C4H9OK) showed optimum hydrogen storage performances. The on-set dehydrogenation temperature of Mg(NH2)2-2LiH-0.08C4H9OK sample was only 70℃, which was 60℃ lower than that of pristine Mg(NH2)2-2LiH sample. After fully dehydrogenated at 130℃, the Mg(NH2)2-2LiH-0.08C4H9OK sample begined to absorb hydrogen at 50℃, which was 50℃ lower than the pristine sample. At 150℃, mass ratio of 3.82% of hydrogen can be rapidly released from the Mg(NH2)2-2LiH-0.08C4H9OK sample within 50 min. The fully dehydrogenated Mg(NH2)2-2LiH-0.08C4H9OK sample could absorb mass ratio of 4.11% hydrogen at 120℃ within 50 min. Adding C4H9OK decreases the dehydrogenation activation energy and reaction enthalpy of the Mg(NH2)2-2LiH system, and enhances the hydrogen desorption kinetic and thermodynamic properties. Mechanistic investigations indicate that C4H9OK acts catalytically to enhance the dehydrogenation properties before 180℃, then it participates in the reaction to generate Li3K(NH2)4 by further increasing the operating temperature.
The hydrogen storage properties of Mg(NH2)2-2LiH system were significantly enhanced by adding a small amount of potassium tert-butoxide (C4H9OK). The 0.08 mol C4H9OK-added sample (Mg(NH2)2-2LiH-0.08C4H9OK) showed optimum hydrogen storage performances. The on-set dehydrogenation temperature of Mg(NH2)2-2LiH-0.08C4H9OK sample was only 70℃, which was 60℃ lower than that of pristine Mg(NH2)2-2LiH sample. After fully dehydrogenated at 130℃, the Mg(NH2)2-2LiH-0.08C4H9OK sample begined to absorb hydrogen at 50℃, which was 50℃ lower than the pristine sample. At 150℃, mass ratio of 3.82% of hydrogen can be rapidly released from the Mg(NH2)2-2LiH-0.08C4H9OK sample within 50 min. The fully dehydrogenated Mg(NH2)2-2LiH-0.08C4H9OK sample could absorb mass ratio of 4.11% hydrogen at 120℃ within 50 min. Adding C4H9OK decreases the dehydrogenation activation energy and reaction enthalpy of the Mg(NH2)2-2LiH system, and enhances the hydrogen desorption kinetic and thermodynamic properties. Mechanistic investigations indicate that C4H9OK acts catalytically to enhance the dehydrogenation properties before 180℃, then it participates in the reaction to generate Li3K(NH2)4 by further increasing the operating temperature.
2021, 37(6): 1106-1112
doi: 10.11862/CJIC.2021.114
Abstract:
Two new complexes of copper(Ⅰ) and copper(Ⅱ) with phenanthridine (Phend) of the following composition : [Cu(κ1-Phend)2Cl2] (1) and [Cu2(κ1-Phend)2(κ1-PPh3)2(μ-Cl)2] (2) have been prepared in the presence of triphenylphosphine (PPh3) as a co-ligand. The structures of these complexes have been investigated by elemental analysis, molar conductivity, FT-IR, UV-Vis, and single-crystal X-ray diffraction. X-ray diffraction analysis of typical complex 1 reveals the distorted square planar geometry around copper(Ⅱ) whereas the binuclear complex 2 was irregular tetrahedral geometry around Cu (Ⅰ) center containing bridge Cl- ion. The FT-IR spectra, elemental analysis as well as UV-Vis spectra confirmed their components, geometries, and ligand interactions. The structures of both complexes have been optimized by density-functional theory (DFT) calculations to explain the electronic spectral properties. CCDC: 1983822, 1; 1983821, 2.
Two new complexes of copper(Ⅰ) and copper(Ⅱ) with phenanthridine (Phend) of the following composition : [Cu(κ1-Phend)2Cl2] (1) and [Cu2(κ1-Phend)2(κ1-PPh3)2(μ-Cl)2] (2) have been prepared in the presence of triphenylphosphine (PPh3) as a co-ligand. The structures of these complexes have been investigated by elemental analysis, molar conductivity, FT-IR, UV-Vis, and single-crystal X-ray diffraction. X-ray diffraction analysis of typical complex 1 reveals the distorted square planar geometry around copper(Ⅱ) whereas the binuclear complex 2 was irregular tetrahedral geometry around Cu (Ⅰ) center containing bridge Cl- ion. The FT-IR spectra, elemental analysis as well as UV-Vis spectra confirmed their components, geometries, and ligand interactions. The structures of both complexes have been optimized by density-functional theory (DFT) calculations to explain the electronic spectral properties. CCDC: 1983822, 1; 1983821, 2.
2021, 37(6): 1113-1124
doi: 10.11862/CJIC.2021.124
Abstract:
Mononuclear Zn2+, Co2+ complexes and binuclear Ni2+ complex based on coumarin Schiff base ligands, [Zn(L1)2] (1) (HL1=6-((4-diethylamino-2-hydroxy-benzylidene)-amino)-benzopyran-2-one), [Co(L2)2] (2) (HL2=6-((4-methoxy-2-hydroxy-benzylidene)-amino)-benzopyran-2-one) and[Ni2(L3)2(CH3OH)4] (3) (H2L3=4-hydroxy-3-((4-methoxy-2-hydroxy-benzylidene)-amino)-benzopyran-2-one), were synthesized and characterized by elemental analysis, IR, UV-Vis, fluorescence spectra and X-ray single crystal diffraction analysis. The crystal structure analysis represents that the complexes 1 and 2 possess mononuclear structure composed of one metal ion (Zn2+ or Co2+) and two ligand units ((L1)- or (L2)-). Whereas complex 3 had binuclear structure, containing two Ni2+ ions, two ligand units (L3)2- and four coordination methanol molecules. The crystals of complexes 1, 2 and 3 are solved as monoclinic space group C2/c, triclinic space group P1 and triclinic space group P21/n, respectively. The spatial configurations of the central metal Zn2+ and Co2+ ions are four-coordinated tetrahedrons, and the Ni2+ ion is six-coordinated twisted octahedrons. In addition, UV-Vis studies demonstrate that the free ligands HL1 in DMF/H2O (4:1, V/V) solution and HL2 in DMSO/H2O (4:1, V/V) solution could selectively recognize Hg2+ and Zn2+, respectively. The detection limits were calculated to be 7.45 and 6.10 μmol·L-1, respectively. Fluorescence studies indicate that HL2 exhibits ability of selective recognition Zn2+ against other common cationic including Ag+, Ba2+, Ca2+, Cd2+, Cr3+, Cu2+, Fe3+, Mg2+, Mn2+ and Hg2+ in DMSO/H2O (4:1, V/V), and the detection limit was calculated to be 2.91 μmol·L-1.
Mononuclear Zn2+, Co2+ complexes and binuclear Ni2+ complex based on coumarin Schiff base ligands, [Zn(L1)2] (1) (HL1=6-((4-diethylamino-2-hydroxy-benzylidene)-amino)-benzopyran-2-one), [Co(L2)2] (2) (HL2=6-((4-methoxy-2-hydroxy-benzylidene)-amino)-benzopyran-2-one) and[Ni2(L3)2(CH3OH)4] (3) (H2L3=4-hydroxy-3-((4-methoxy-2-hydroxy-benzylidene)-amino)-benzopyran-2-one), were synthesized and characterized by elemental analysis, IR, UV-Vis, fluorescence spectra and X-ray single crystal diffraction analysis. The crystal structure analysis represents that the complexes 1 and 2 possess mononuclear structure composed of one metal ion (Zn2+ or Co2+) and two ligand units ((L1)- or (L2)-). Whereas complex 3 had binuclear structure, containing two Ni2+ ions, two ligand units (L3)2- and four coordination methanol molecules. The crystals of complexes 1, 2 and 3 are solved as monoclinic space group C2/c, triclinic space group P1 and triclinic space group P21/n, respectively. The spatial configurations of the central metal Zn2+ and Co2+ ions are four-coordinated tetrahedrons, and the Ni2+ ion is six-coordinated twisted octahedrons. In addition, UV-Vis studies demonstrate that the free ligands HL1 in DMF/H2O (4:1, V/V) solution and HL2 in DMSO/H2O (4:1, V/V) solution could selectively recognize Hg2+ and Zn2+, respectively. The detection limits were calculated to be 7.45 and 6.10 μmol·L-1, respectively. Fluorescence studies indicate that HL2 exhibits ability of selective recognition Zn2+ against other common cationic including Ag+, Ba2+, Ca2+, Cd2+, Cr3+, Cu2+, Fe3+, Mg2+, Mn2+ and Hg2+ in DMSO/H2O (4:1, V/V), and the detection limit was calculated to be 2.91 μmol·L-1.
2021, 37(6): 1125-1134
doi: 10.11862/CJIC.2021.105
Abstract:
The commercialization process of Li-S battery is seriously impeded by the poor performance of sulfur cathode, including the low conductivity and dissatisfactory activity for facilitating the polysulfide conversion. In this work, we developed a scale-up method to synthesize an efficient cathode material (Co-N-C@KB) with abundant Co-N-C active sites on the Ketjen Black (KB), through a ligand-mediated-synthesis and a low-temperature-pyrolysis strategy. The uniformly distributed Co-N-C active sites were proved to be favorable for the conversion of polysulfide at the cathode, hence improving the capacity and cyclic life of Li-S battery. As a result, the Co-N-C@KB cathode for the Li-S battery could deliver an initial discharge specific capacity as high as 1 442 mAh·g-1, and have the excellent capability for capacity retention during the long-term stability test.
The commercialization process of Li-S battery is seriously impeded by the poor performance of sulfur cathode, including the low conductivity and dissatisfactory activity for facilitating the polysulfide conversion. In this work, we developed a scale-up method to synthesize an efficient cathode material (Co-N-C@KB) with abundant Co-N-C active sites on the Ketjen Black (KB), through a ligand-mediated-synthesis and a low-temperature-pyrolysis strategy. The uniformly distributed Co-N-C active sites were proved to be favorable for the conversion of polysulfide at the cathode, hence improving the capacity and cyclic life of Li-S battery. As a result, the Co-N-C@KB cathode for the Li-S battery could deliver an initial discharge specific capacity as high as 1 442 mAh·g-1, and have the excellent capability for capacity retention during the long-term stability test.
2021, 37(6): 1135-1142
doi: 10.11862/CJIC.2021.132
Abstract:
Two 3D manganese(Ⅱ) and cadmium(Ⅱ) coordination polymers, namely[M(μ4-H2DTA)(bipy)]n (M=Mn (1), Cd (2)), have been constructed hydrothermally using H4DTA (H4DTA=2, 3-dihydroxy-terephthalic acid), bipy (bipy=2, 2'-bipyridine), and manganese or cadmium chlorides. Single-crystal X-ray diffraction analyses reveal that two complexes are isostructural and crystallize in the orthorhombic system, space groups Pnna. Both complexes disclose a 3D metal-organic framework. The luminescent and catalytic properties of two complexes were investigated. Complex 1 exhibited good catalytic performance for the cyanosilylation reaction. CCDC: 2060258, 1; 2060259, 2.
Two 3D manganese(Ⅱ) and cadmium(Ⅱ) coordination polymers, namely[M(μ4-H2DTA)(bipy)]n (M=Mn (1), Cd (2)), have been constructed hydrothermally using H4DTA (H4DTA=2, 3-dihydroxy-terephthalic acid), bipy (bipy=2, 2'-bipyridine), and manganese or cadmium chlorides. Single-crystal X-ray diffraction analyses reveal that two complexes are isostructural and crystallize in the orthorhombic system, space groups Pnna. Both complexes disclose a 3D metal-organic framework. The luminescent and catalytic properties of two complexes were investigated. Complex 1 exhibited good catalytic performance for the cyanosilylation reaction. CCDC: 2060258, 1; 2060259, 2.
2021, 37(6): 1143-1151
doi: 10.11862/CJIC.2021.095
Abstract:
Pd nanoparticles with different (111) facet proportions were prepared at by a liquid phase hydrogen reduction method, then preparing corresponding Pd/C catalysts. The results of transmission electron microscopy (TEM), fast Fourie transition (FFT), and X-ray diffraction (XRD) revealed that the proportion of the (111) facets on the Pd surface was higher at lower temperatures. Hydrogen oxygen pulse titration (H2-O2) and H2-temperature programmed desorption (H2-TPD) showed that the hydrogen adsorption volume of Pd/C catalysts was correlated linearly with the Pd(111) facet proportions. All Pd/C catalysts had an average particle size of 4.3 nm with narrow particle size distribution, which could eliminated the effect of particle size. The similar pore parameters and Pd loading of all catalysts allowed the reasonable comparison for Pd(111) facet proportions influenced the hydrogenation performance in three typical reactions. Moreover, linear correlations were found between the H2 consumption rate with Pd (111) facet proportions in each of styrene, cyclohexene, and p-nitrotoluene hydrogenation. The good catalytic performance of high Pd(111) facet proportion catalyst for hydrogenations could be attributed to the H2 molecule prior to absorbed the Pd(111) facet promoting the formation of dissociated hydrogen atoms. These results above indicated that Pd-based catalysts with high (111) facet proportion facilitated hydrogenation performance.
Pd nanoparticles with different (111) facet proportions were prepared at by a liquid phase hydrogen reduction method, then preparing corresponding Pd/C catalysts. The results of transmission electron microscopy (TEM), fast Fourie transition (FFT), and X-ray diffraction (XRD) revealed that the proportion of the (111) facets on the Pd surface was higher at lower temperatures. Hydrogen oxygen pulse titration (H2-O2) and H2-temperature programmed desorption (H2-TPD) showed that the hydrogen adsorption volume of Pd/C catalysts was correlated linearly with the Pd(111) facet proportions. All Pd/C catalysts had an average particle size of 4.3 nm with narrow particle size distribution, which could eliminated the effect of particle size. The similar pore parameters and Pd loading of all catalysts allowed the reasonable comparison for Pd(111) facet proportions influenced the hydrogenation performance in three typical reactions. Moreover, linear correlations were found between the H2 consumption rate with Pd (111) facet proportions in each of styrene, cyclohexene, and p-nitrotoluene hydrogenation. The good catalytic performance of high Pd(111) facet proportion catalyst for hydrogenations could be attributed to the H2 molecule prior to absorbed the Pd(111) facet promoting the formation of dissociated hydrogen atoms. These results above indicated that Pd-based catalysts with high (111) facet proportion facilitated hydrogenation performance.
