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2023 Volume 39 Issue 12
2023, 39(12): 2241-2255
doi: 10.11862/CJIC.2023.206
Abstract:
Revolutionary changes in energy storage technology have put forward higher requirements on next-generation anode materials for lithium-ion battery. Recently, a new class of materials with complex stoichiometric ratios, high entropy oxides (HEOs), has gradually emerging into sight and embracing the prosperity. The ideal elemental adjustability and attractive synergistic effect make HEOs promising to break through the integrated performance bottleneck of conventional anodes and provide new impetus for the design and development of electrochemical energy storage materials. Here, this review shares our unique viewpoints through an overview of the research status of HEOs anodes and specific descriptions regarding material design and electrochemical behavior. Specifically, the chemical composition regulation and structure design by combing the recent research of our group and important domestic and foreign literature. The control of intrinsic activity of HEOs including the introduction of metal heteroatom doping and non-metallic heteroatom doping. The influence of the increase of active-sites of HEOs to promote lithium storage performance is reviewed from the structural design including the construction of one-dimensional structures, two-dimensional structures, three-dimensional structures, hollow structures, carbon material composite. Finally, we envision the prospects and related challenges in this field, which will bring some enlightening guidance and criteria for researchers to further unlock the mysteries of HEO anodes.
Revolutionary changes in energy storage technology have put forward higher requirements on next-generation anode materials for lithium-ion battery. Recently, a new class of materials with complex stoichiometric ratios, high entropy oxides (HEOs), has gradually emerging into sight and embracing the prosperity. The ideal elemental adjustability and attractive synergistic effect make HEOs promising to break through the integrated performance bottleneck of conventional anodes and provide new impetus for the design and development of electrochemical energy storage materials. Here, this review shares our unique viewpoints through an overview of the research status of HEOs anodes and specific descriptions regarding material design and electrochemical behavior. Specifically, the chemical composition regulation and structure design by combing the recent research of our group and important domestic and foreign literature. The control of intrinsic activity of HEOs including the introduction of metal heteroatom doping and non-metallic heteroatom doping. The influence of the increase of active-sites of HEOs to promote lithium storage performance is reviewed from the structural design including the construction of one-dimensional structures, two-dimensional structures, three-dimensional structures, hollow structures, carbon material composite. Finally, we envision the prospects and related challenges in this field, which will bring some enlightening guidance and criteria for researchers to further unlock the mysteries of HEO anodes.
2023, 39(12): 2256-2264
doi: 10.11862/CJIC.2023.199
Abstract:
The effects of different temperatures and different solution components (introduction of I-) on the gold nanotetrapods (GNTPs) reshaping process were investigated, revealing that the GNTPs reshaping mechanism is Ostwald ripening, that is, the dissolution of weakly bound surface atoms of Au at areas with high convex curvature and re-deposition at concave areas. This reshaping process can be stopped at any time in a few seconds by a thin layer of silver coating, and the morphology of GNTPs can be well stabilized to the greatest extent, thereby also preventing the evolution of optical properties. On this basis, the stability of GNTPs/Ag was further investigated by ultraviolet-visible-near-infrared (UV-Vis-NIR) absorption spectroscopy and synchrotron-based small-angle X-ray scattering (SAXS), as well as GNTPs/Ag results in an optical response, which is demonstrated by surface-enhanced Raman scattering (SERS) spectroscopy.
The effects of different temperatures and different solution components (introduction of I-) on the gold nanotetrapods (GNTPs) reshaping process were investigated, revealing that the GNTPs reshaping mechanism is Ostwald ripening, that is, the dissolution of weakly bound surface atoms of Au at areas with high convex curvature and re-deposition at concave areas. This reshaping process can be stopped at any time in a few seconds by a thin layer of silver coating, and the morphology of GNTPs can be well stabilized to the greatest extent, thereby also preventing the evolution of optical properties. On this basis, the stability of GNTPs/Ag was further investigated by ultraviolet-visible-near-infrared (UV-Vis-NIR) absorption spectroscopy and synchrotron-based small-angle X-ray scattering (SAXS), as well as GNTPs/Ag results in an optical response, which is demonstrated by surface-enhanced Raman scattering (SERS) spectroscopy.
2023, 39(12): 2279-2286
doi: 10.11862/CJIC.2023.196
Abstract:
In this work, novel terpyridine-Fe(Ⅱ) coordination polymers were prepared by introducing an aromatic ring as a π-spacer between two terpyridine units to construct multi-dented ligands, which were coordinated with Iron(Ⅱ) tetrafluoroborate hexahydrate. The electrochromic properties of the terpyridine-Fe(Ⅱ) coordination polymers were investigated. The results indicated that the introduction of fluorine atoms on the aromatic ring had a certain effect on their electrochromic properties. Among them, coordination polymer Fe-F2 prepared derived from the ligand F2 containing two fluorine atoms showed excellent electrochromic properties (optical contrast up to 69%, response time as short as 0.5 s, coloration efficiency over 320 cm2·C-1).
In this work, novel terpyridine-Fe(Ⅱ) coordination polymers were prepared by introducing an aromatic ring as a π-spacer between two terpyridine units to construct multi-dented ligands, which were coordinated with Iron(Ⅱ) tetrafluoroborate hexahydrate. The electrochromic properties of the terpyridine-Fe(Ⅱ) coordination polymers were investigated. The results indicated that the introduction of fluorine atoms on the aromatic ring had a certain effect on their electrochromic properties. Among them, coordination polymer Fe-F2 prepared derived from the ligand F2 containing two fluorine atoms showed excellent electrochromic properties (optical contrast up to 69%, response time as short as 0.5 s, coloration efficiency over 320 cm2·C-1).
2023, 39(12): 2287-2294
doi: 10.11862/CJIC.2023.210
Abstract:
To investigate mechanism of carbon coating on the high-temperature cycle performance of widely used LiFePO4/graphite batteries, two types of LiFePO4 cathode material with different carbon coating degrees were prepared. According to characterization results from X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), powder resistance, and coin cell, two types of LiFePO4 were almost identical with respect to the crystal structure, particle size, and specific capacity. Then LiFePO4/graphite pouch cells were prepared and cycled at 1C under 60 ℃. It turns out that carbon coating can improve capacity retention from 80.4% to 84.9% after 1 251 cycles. The capacity improvement for polarization capacity and thermodynamic capacity account for 76% and 24%, respectively. This demonstrates that the mechanism of carbon coating is to reduce the polarization capacity loss by forming integrated conducting networks. In contrast, carbon coating can not inhibit Fe dissolution directly. Instead, it may be an indirect interaction through the reduction of moisture.
To investigate mechanism of carbon coating on the high-temperature cycle performance of widely used LiFePO4/graphite batteries, two types of LiFePO4 cathode material with different carbon coating degrees were prepared. According to characterization results from X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), powder resistance, and coin cell, two types of LiFePO4 were almost identical with respect to the crystal structure, particle size, and specific capacity. Then LiFePO4/graphite pouch cells were prepared and cycled at 1C under 60 ℃. It turns out that carbon coating can improve capacity retention from 80.4% to 84.9% after 1 251 cycles. The capacity improvement for polarization capacity and thermodynamic capacity account for 76% and 24%, respectively. This demonstrates that the mechanism of carbon coating is to reduce the polarization capacity loss by forming integrated conducting networks. In contrast, carbon coating can not inhibit Fe dissolution directly. Instead, it may be an indirect interaction through the reduction of moisture.
2023, 39(12): 2295-2300
doi: 10.11862/CJIC.2023.198
Abstract:
We performed a coordination reaction between ligand 3-(5-(3-pyridyl)-2-(1, 3, 4-oxadiazoles))thio)-2, 4-glutaric ketone (L1) and AgSbF6 to obtain a coordination polymer {[Ag(L1)2]SbF6}n (1). The ligand 3-((5-(4-pyridyl)-2-(1, 3, 4-oxadiazole))thio-2, 4-pentanedione (L2) was used to react with AgCF3SO3 to obtain a coordination polymer [Ag(L2)(CF3SO3)]n (2). The structures of the two complexes were characterized by powder X-ray diffraction, infrared spectroscopy, elemental analysis, and single-crystal X-ray diffraction. In the solid state, coordination polymers 1 and 2 form 1D chain structures, and the coordination configuration of Ag(Ⅰ) ions is a twisted tetrahedron. The carbonyl oxygen atoms of the β-diketone units in the two complexes do not coordinate with Ag(Ⅰ) ions, providing the possibility for constructing heteronuclear complexes.
We performed a coordination reaction between ligand 3-(5-(3-pyridyl)-2-(1, 3, 4-oxadiazoles))thio)-2, 4-glutaric ketone (L1) and AgSbF6 to obtain a coordination polymer {[Ag(L1)2]SbF6}n (1). The ligand 3-((5-(4-pyridyl)-2-(1, 3, 4-oxadiazole))thio-2, 4-pentanedione (L2) was used to react with AgCF3SO3 to obtain a coordination polymer [Ag(L2)(CF3SO3)]n (2). The structures of the two complexes were characterized by powder X-ray diffraction, infrared spectroscopy, elemental analysis, and single-crystal X-ray diffraction. In the solid state, coordination polymers 1 and 2 form 1D chain structures, and the coordination configuration of Ag(Ⅰ) ions is a twisted tetrahedron. The carbonyl oxygen atoms of the β-diketone units in the two complexes do not coordinate with Ag(Ⅰ) ions, providing the possibility for constructing heteronuclear complexes.
2023, 39(12): 2301-2310
doi: 10.11862/CJIC.2023.203
Abstract:
A Cd-based metal-organic framework with the formula (Me2NH2)[Cd(BTB)(DMF)]·DMF·H2O (Cd-MOF) has been synthesized via the solvothermal method using 1, 3, 5-tris(4-carboxyphenyl)benzene (H3BTB) as a ligand, and its structure was characterized by single crystal X-ray diffraction, powder X-ray diffraction, elemental analysis, and thermogravimetric analysis. It could selectively detect acetone and Fe3+ ions by fluorescence quenching with the detection limits (volume fraction and concentration) of 0.6% and 0.89 μmol·L-1, respectively. The linear detection ranges of 2.0%-2.5% for acetone and 0-0.05 mmol·L-1 for Fe3+ ions were observed. Time response and recyclability experiments confirmed that Cd-MOF is a reliable and efficient fluorescence sensor for the long-term detection of acetone molecules and Fe3+ ions.
A Cd-based metal-organic framework with the formula (Me2NH2)[Cd(BTB)(DMF)]·DMF·H2O (Cd-MOF) has been synthesized via the solvothermal method using 1, 3, 5-tris(4-carboxyphenyl)benzene (H3BTB) as a ligand, and its structure was characterized by single crystal X-ray diffraction, powder X-ray diffraction, elemental analysis, and thermogravimetric analysis. It could selectively detect acetone and Fe3+ ions by fluorescence quenching with the detection limits (volume fraction and concentration) of 0.6% and 0.89 μmol·L-1, respectively. The linear detection ranges of 2.0%-2.5% for acetone and 0-0.05 mmol·L-1 for Fe3+ ions were observed. Time response and recyclability experiments confirmed that Cd-MOF is a reliable and efficient fluorescence sensor for the long-term detection of acetone molecules and Fe3+ ions.
2023, 39(12): 2311-2316
doi: 10.11862/CJIC.2023.194
Abstract:
In this work, two series of phosphors were prepared using high-temperature solid-state reactions: Ba2-xZnGe2O7∶xBi3+ (series Ⅰ) and Ba1.994-yKyZnGe2O7∶0.006Bi3+ (series Ⅱ). X-ray diffraction (XRD) analysis demonstrated that the doping of a small amount of Bi3+ and K+ did not significantly change the phase structure of the material. The fluorescence spectra of the samples were obtained using a fluorescence spectrometer. The results indicated that the luminescence colors of both series remained yellow-green despite a slight variation in the luminescence spectra with changes in composition. Excitation at 358 nm led to the phosphor exhibiting a broad emission band with its peak at 500 nm, which corresponded to the energy level transition from 3P1 to 1S0. When monitoring at 500 nm, the strongest excitation peak occurred at 358 nm, representing the energy level transition from 1S0 to 3P1. Furthermore, a shoulder peak at 320 nm was observed, indicating a charge transfer band between O2- and Bi3+. Analysis of the spectral data for series Ⅰ suggested that the optimal doping amount of Bi3+ was x=0.006. In this matrix, the substitution of Ba2+ by Bi3+ introduced an unequal substitution, leading to the generation of Ba2+ vacancies or interstitial O2- within the lattice, which had a negative impact on the luminous intensity of the material. Co-doping with K+ acted as a charge compensator, effectively cancelling out the Ba2+ vacancies or interstitial O2- by generating interstitial K+ or oxygen vacancies. Consequently, this process reduced lattice distortion and improved luminescent intensity. Further analysis of the spectral data for series Ⅱ revealed that the fully charge-compensated phosphor sample exhibited luminescent intensity about 2.5 times higher than that of the sample without K+ doping.
In this work, two series of phosphors were prepared using high-temperature solid-state reactions: Ba2-xZnGe2O7∶xBi3+ (series Ⅰ) and Ba1.994-yKyZnGe2O7∶0.006Bi3+ (series Ⅱ). X-ray diffraction (XRD) analysis demonstrated that the doping of a small amount of Bi3+ and K+ did not significantly change the phase structure of the material. The fluorescence spectra of the samples were obtained using a fluorescence spectrometer. The results indicated that the luminescence colors of both series remained yellow-green despite a slight variation in the luminescence spectra with changes in composition. Excitation at 358 nm led to the phosphor exhibiting a broad emission band with its peak at 500 nm, which corresponded to the energy level transition from 3P1 to 1S0. When monitoring at 500 nm, the strongest excitation peak occurred at 358 nm, representing the energy level transition from 1S0 to 3P1. Furthermore, a shoulder peak at 320 nm was observed, indicating a charge transfer band between O2- and Bi3+. Analysis of the spectral data for series Ⅰ suggested that the optimal doping amount of Bi3+ was x=0.006. In this matrix, the substitution of Ba2+ by Bi3+ introduced an unequal substitution, leading to the generation of Ba2+ vacancies or interstitial O2- within the lattice, which had a negative impact on the luminous intensity of the material. Co-doping with K+ acted as a charge compensator, effectively cancelling out the Ba2+ vacancies or interstitial O2- by generating interstitial K+ or oxygen vacancies. Consequently, this process reduced lattice distortion and improved luminescent intensity. Further analysis of the spectral data for series Ⅱ revealed that the fully charge-compensated phosphor sample exhibited luminescent intensity about 2.5 times higher than that of the sample without K+ doping.
2023, 39(12): 2317-2327
doi: 10.11862/CJIC.2023.169
Abstract:
A 2D nickel-manganese layered double hydroxide was generated on the surface of carbon cloth (CC) by hydrothermal method, and it was converted into a two-dimensional Ni-Mn metal-organic framework Ni-Mn (MOF) by solvothermal method, and its morphology could be maintained well. The effects of molar ratio of Ni and Mn, reaction temperature, and reaction time on the morphology, structure, and properties of the material were investigated. The optimal electrochemical performance of the Ni-Mn MOF/CC electrode was achieved when the molar ratio of Ni and Mn elements was 9∶1, the reaction temperature was 120 ℃, and the reaction time was 12 hours, respectively. The area specific capacitance of the electrode can be reached as high as 4 007.5 mF·cm-2 at a current density of 1 mA·cm-2, and it showed good cycling stability. The electrode can be applied to a flexible symmetric supercapacitor, which can be bent 180°. The capacitance retention rate was 83.6% after 5 000 cycles at a current density of 10 mA·cm-2, demonstrating good cycling stability and flexibility.
A 2D nickel-manganese layered double hydroxide was generated on the surface of carbon cloth (CC) by hydrothermal method, and it was converted into a two-dimensional Ni-Mn metal-organic framework Ni-Mn (MOF) by solvothermal method, and its morphology could be maintained well. The effects of molar ratio of Ni and Mn, reaction temperature, and reaction time on the morphology, structure, and properties of the material were investigated. The optimal electrochemical performance of the Ni-Mn MOF/CC electrode was achieved when the molar ratio of Ni and Mn elements was 9∶1, the reaction temperature was 120 ℃, and the reaction time was 12 hours, respectively. The area specific capacitance of the electrode can be reached as high as 4 007.5 mF·cm-2 at a current density of 1 mA·cm-2, and it showed good cycling stability. The electrode can be applied to a flexible symmetric supercapacitor, which can be bent 180°. The capacitance retention rate was 83.6% after 5 000 cycles at a current density of 10 mA·cm-2, demonstrating good cycling stability and flexibility.
2023, 39(12): 2328-2338
doi: 10.11862/CJIC.2023.193
Abstract:
3.5MgO·0.5MgF2·GeO2∶Mn4+ has been applied in the market as a red phosphor with excellent thermal stability and good luminescence performance. However, the unclear influence mechanism of MgF2 in the phosphor hinders further performance optimization and development. A series of Mn4+-activated germanate phosphors were prepared by the high-temperature solid-phase method. The variation regulation of the structure, morphology, and luminescence performance was investigated by comparing the addition of MgF2 and H3BO3 (flux). Then the luminescence influence role of MgF2 has been obtained. The study showed that the optimum sintering temperatures for the samples with MgF2, H3BO3, and without any co-solvent were 1 150, 1 250, and 1 350 ℃, respectively. The luminescence intensity at the above temperatures was also the optimum value, and the samples with MgF2 and H3BO3 exhibited a pure phase at the temperature, respectively. The crystallinity and dispersion of the phosphors were improved by adding MgF2 and H3BO3, and the positive influence of the MgF2 was better than that of the H3BO3. The Dq/B value of the phosphor with MgF2 was calculated to be 3.03, indicating Mn4+ is in an environment with a strong crystal field. The fluorescence lifetimes of the phosphors with MgF2 and H3BO3 were 0.93 and 0.75 ms, respectively. The addition of MgF2, on the one hand, plays a positive role as a co-solvent, which can be conducive to generating a pure phase and improving the crystallinity. The role is the same as the H3BO3. On the other hand, the F- ions originating from MgF2 were successfully doped into the crystal lattice confirmed by the XPS analysis, and then the crystal structure of Mg14Ge5(O, F)24 was achieved.
3.5MgO·0.5MgF2·GeO2∶Mn4+ has been applied in the market as a red phosphor with excellent thermal stability and good luminescence performance. However, the unclear influence mechanism of MgF2 in the phosphor hinders further performance optimization and development. A series of Mn4+-activated germanate phosphors were prepared by the high-temperature solid-phase method. The variation regulation of the structure, morphology, and luminescence performance was investigated by comparing the addition of MgF2 and H3BO3 (flux). Then the luminescence influence role of MgF2 has been obtained. The study showed that the optimum sintering temperatures for the samples with MgF2, H3BO3, and without any co-solvent were 1 150, 1 250, and 1 350 ℃, respectively. The luminescence intensity at the above temperatures was also the optimum value, and the samples with MgF2 and H3BO3 exhibited a pure phase at the temperature, respectively. The crystallinity and dispersion of the phosphors were improved by adding MgF2 and H3BO3, and the positive influence of the MgF2 was better than that of the H3BO3. The Dq/B value of the phosphor with MgF2 was calculated to be 3.03, indicating Mn4+ is in an environment with a strong crystal field. The fluorescence lifetimes of the phosphors with MgF2 and H3BO3 were 0.93 and 0.75 ms, respectively. The addition of MgF2, on the one hand, plays a positive role as a co-solvent, which can be conducive to generating a pure phase and improving the crystallinity. The role is the same as the H3BO3. On the other hand, the F- ions originating from MgF2 were successfully doped into the crystal lattice confirmed by the XPS analysis, and then the crystal structure of Mg14Ge5(O, F)24 was achieved.
ZnCr2O4/ZSM-5@Silicalite-1 to optimize the selectivity of one-step hydrogenation of CO2 to aromatics
2023, 39(12): 2339-2348
doi: 10.11862/CJIC.2023.195
Abstract:
The CO2 hydrogenation reaction over the oxide-zeolite bifunctional catalyst yields a mixture of BTX (benzene, toluene, and xylene), C9, and C10+ aromatic products, among which BTX is of the highest commercial value. To improve the distribution of the aromatic products and promote the production of BTX, the core-shell structured zeolite ZSM-5@Silicalite-1 was prepared by the epitaxial growth method in this work. According to the characterization results of powder X-ray diffraction (PXRD), N2 adsorption-desorption, temperature-programmed desorption of NH3 (NH3-TPD), scanning electron microscope (SEM), transmission electron microscopy (TEM), and pyridine adsorption Fourier transform infrared spectroscopy (Py-IR), the inert Silicalite-1 shell is uniformly coated on the external surface of the ZSM-5 core, therefore changes its acidic properties especially reduces the external acidity, which contributes to improving the aromatic distribution. When applied in the one-step CO2-to-aromatic reaction, the combination of ZSM-5@Silicalite-1 and Zn-Cr oxide resulted in a CO2 conversion of 21.9% and aromatics selectivity of 79.3% under the conditions of VH2/VCO2=3.0, 1 200 mL·g-1·h-1, 320 ℃, and 4.0 MPa, and it gave a 33.5% of light aromatics in the overall aromatics, which was higher than 14.8% over the ZnCr2O4/ZSM-5 system. Additionally, in the one-step CO2-to-aromatic reaction system, the by-products of CO and H2O are generated from the side reaction of reverse water-gas shift (RWGS). Due to the higher hydrophobicity of Silicalite-1 than ZSM-5, H2O is enriched at the interface between the oxide and core-shell zeolite, which can shift the reaction equilibrium of RWGS, thus inhibiting the generation of CO. As a result, the CO selectivity was significantly reduced at high space velocities compared with the unmodified oxide-zeolite system. At an optimal shell thickness, the ZnCr2O4/ZSM-5@Silicalite-1 bifunctional catalyst obtained a space-time yield of aromatics of 2.4 mmol·g-1·h-1 at 8 400 mL·g-1·h-1, which was 22% higher compared with ZnCr2O4/ZSM-5.
The CO2 hydrogenation reaction over the oxide-zeolite bifunctional catalyst yields a mixture of BTX (benzene, toluene, and xylene), C9, and C10+ aromatic products, among which BTX is of the highest commercial value. To improve the distribution of the aromatic products and promote the production of BTX, the core-shell structured zeolite ZSM-5@Silicalite-1 was prepared by the epitaxial growth method in this work. According to the characterization results of powder X-ray diffraction (PXRD), N2 adsorption-desorption, temperature-programmed desorption of NH3 (NH3-TPD), scanning electron microscope (SEM), transmission electron microscopy (TEM), and pyridine adsorption Fourier transform infrared spectroscopy (Py-IR), the inert Silicalite-1 shell is uniformly coated on the external surface of the ZSM-5 core, therefore changes its acidic properties especially reduces the external acidity, which contributes to improving the aromatic distribution. When applied in the one-step CO2-to-aromatic reaction, the combination of ZSM-5@Silicalite-1 and Zn-Cr oxide resulted in a CO2 conversion of 21.9% and aromatics selectivity of 79.3% under the conditions of VH2/VCO2=3.0, 1 200 mL·g-1·h-1, 320 ℃, and 4.0 MPa, and it gave a 33.5% of light aromatics in the overall aromatics, which was higher than 14.8% over the ZnCr2O4/ZSM-5 system. Additionally, in the one-step CO2-to-aromatic reaction system, the by-products of CO and H2O are generated from the side reaction of reverse water-gas shift (RWGS). Due to the higher hydrophobicity of Silicalite-1 than ZSM-5, H2O is enriched at the interface between the oxide and core-shell zeolite, which can shift the reaction equilibrium of RWGS, thus inhibiting the generation of CO. As a result, the CO selectivity was significantly reduced at high space velocities compared with the unmodified oxide-zeolite system. At an optimal shell thickness, the ZnCr2O4/ZSM-5@Silicalite-1 bifunctional catalyst obtained a space-time yield of aromatics of 2.4 mmol·g-1·h-1 at 8 400 mL·g-1·h-1, which was 22% higher compared with ZnCr2O4/ZSM-5.
2023, 39(12): 2349-2357
doi: 10.11862/CJIC.2023.202
Abstract:
In this work, the influences of electrophoretic voltage on film deposition rate, thickness and morphology were investigated. Photoanodes and dye-sensitized solar cells (DSSC) were characterized by step profiler, optical photograph, scanning electron microscope, electrochemical impedance spectroscopy (EIS) and open-circuit voltage decay (OCVD). Increasing electrophoretic voltage can accelerate deposition rate and increase the final film thickness. However, employing excessively high voltage leads to crack formation and incomplete coverage on FTO, thereby exerting an adverse impact on the efficiency of DSSC devices. By employing a "30 V followed by 60 V" deposition method, which combines the advantages of low and high voltages, photoanodes exhibiting a synergistic effect were successfully fabricated. This approach not only reduces electrophoretic time but also yields films of superior quality, resulting in an impressive device efficiency of 7.29% without any additional modifications.
In this work, the influences of electrophoretic voltage on film deposition rate, thickness and morphology were investigated. Photoanodes and dye-sensitized solar cells (DSSC) were characterized by step profiler, optical photograph, scanning electron microscope, electrochemical impedance spectroscopy (EIS) and open-circuit voltage decay (OCVD). Increasing electrophoretic voltage can accelerate deposition rate and increase the final film thickness. However, employing excessively high voltage leads to crack formation and incomplete coverage on FTO, thereby exerting an adverse impact on the efficiency of DSSC devices. By employing a "30 V followed by 60 V" deposition method, which combines the advantages of low and high voltages, photoanodes exhibiting a synergistic effect were successfully fabricated. This approach not only reduces electrophoretic time but also yields films of superior quality, resulting in an impressive device efficiency of 7.29% without any additional modifications.
2023, 39(12): 2265-2278
doi: 10.11862/CJIC.2023.205
Abstract:
Constructed by the ligands of 3-amino-1,2,4-triazole-5-carboxylic acid (Hatz) and 1,3,5-benzenetricarboxylic acid (H3btc), a Zn(Ⅱ) metal-organic framework with nanosheet morphology (Zn-MOF-1-NS) was prepared to mimic the structures of matrix metalloproteinases (MMPs). Zn-MOF-1-NS was highly effective in catalyzing the hydrolysis of the peptide bonds of microcystin (MC-LR). Within just 7.5 h, 82.6% of MC-LR was hydrolyzed (k=0.23 h-1), which was much higher than the reported best hydrolysis efficiency of siderite (k=0.04 h-1). This research has found that even when the amount of humic acid was increased tenfold, it did not significantly impede MC-LR decomposition. This demonstrates the impressive ability of the catalyst to resist interference from natural organic matter (NOM). Through in-situ attenuated total reflectance Fourier transform infrared spectroscopy (in-situ ATR-FTIR) and X-ray photoelectron spectroscopy (XPS) analyses, theoretical calculations, and comparison with a non-carboxyl counterpart, it was discovered that the surficial Zn(Ⅱ) site and the carboxyl group of Zn-MOF-1-NS participate in the cleavage of the peptide bond.
Constructed by the ligands of 3-amino-1,2,4-triazole-5-carboxylic acid (Hatz) and 1,3,5-benzenetricarboxylic acid (H3btc), a Zn(Ⅱ) metal-organic framework with nanosheet morphology (Zn-MOF-1-NS) was prepared to mimic the structures of matrix metalloproteinases (MMPs). Zn-MOF-1-NS was highly effective in catalyzing the hydrolysis of the peptide bonds of microcystin (MC-LR). Within just 7.5 h, 82.6% of MC-LR was hydrolyzed (k=0.23 h-1), which was much higher than the reported best hydrolysis efficiency of siderite (k=0.04 h-1). This research has found that even when the amount of humic acid was increased tenfold, it did not significantly impede MC-LR decomposition. This demonstrates the impressive ability of the catalyst to resist interference from natural organic matter (NOM). Through in-situ attenuated total reflectance Fourier transform infrared spectroscopy (in-situ ATR-FTIR) and X-ray photoelectron spectroscopy (XPS) analyses, theoretical calculations, and comparison with a non-carboxyl counterpart, it was discovered that the surficial Zn(Ⅱ) site and the carboxyl group of Zn-MOF-1-NS participate in the cleavage of the peptide bond.
2023, 39(12): 2358-2366
doi: 10.11862/CJIC.2023.191
Abstract:
Three coordination polymers (CPs), namely, {[Ni(L1)(H2O)4]·2H2O}n (1), [Zn(L1)(DMA)2]n (2), and [Co(L2)(DMF)2]n (3) (DMA=N, N-dimethylacetamide, DMF=N, N-dimethylformamide) were synthesized based on dicarboxylate ligands 2, 2′-(1, 4-phenylenebis(methylene))bis(sulfanediyl)dibenzoic acid (H2L1) and 2, 2′-(2, 3, 5, 6-tetramethyl-1, 4-phenylene)bis(methylene)bis(sulfanediyl)dibenzoic acid (H2L2) under solvothermal conditions. Complexes 1-3 have been structurally characterized by single-crystal X-ray diffraction analyses and characterized by elemental analysis, infrared spectra, thermogravimetric analysis, powder X-ray diffraction, and solid-state UV-Vis spectrum. They have zigzag chain structures and the ligands all display anti-conformation. Besides, the chains in 1-3 further form 3D frameworks by hydrogen bonding interactions. Furthermore, the solid-state fluorescence property of 2 was investigated.
Three coordination polymers (CPs), namely, {[Ni(L1)(H2O)4]·2H2O}n (1), [Zn(L1)(DMA)2]n (2), and [Co(L2)(DMF)2]n (3) (DMA=N, N-dimethylacetamide, DMF=N, N-dimethylformamide) were synthesized based on dicarboxylate ligands 2, 2′-(1, 4-phenylenebis(methylene))bis(sulfanediyl)dibenzoic acid (H2L1) and 2, 2′-(2, 3, 5, 6-tetramethyl-1, 4-phenylene)bis(methylene)bis(sulfanediyl)dibenzoic acid (H2L2) under solvothermal conditions. Complexes 1-3 have been structurally characterized by single-crystal X-ray diffraction analyses and characterized by elemental analysis, infrared spectra, thermogravimetric analysis, powder X-ray diffraction, and solid-state UV-Vis spectrum. They have zigzag chain structures and the ligands all display anti-conformation. Besides, the chains in 1-3 further form 3D frameworks by hydrogen bonding interactions. Furthermore, the solid-state fluorescence property of 2 was investigated.
2023, 39(12): 2367-2376
doi: 10.11862/CJIC.2023.204
Abstract:
In this paper, four di-iron complexes with an isoxazole moiety were synthesized and characterized. The reaction of a hydroxy-containing di-iron complex [Fe2(CO)6(μ-SCH2CH(CH2OH)S)] (1) with 5-methylisoxazole-4-carboxylic acid gave an ester product, named [Fe2(CO)6(μ-SCH2CHCH2OOC(5-C3HNOCH3)S)] (2) in very good yield. The phosphine-bearing analogues, which are named [Fe2(CO)5(L)(μ-SCH2CHCH2OOC(5-C3HNOCH3)S)] where L= P(4-C6H4CH3)3 (3), P(4-C6H4F)3 (4), P(2-C6H4OCH3)3 (5), were prepared by the reactions of complex 2 with a monophosphine ligand tri(p-tolyl)phosphine, tris(4-fluorophenyl)phosphine or tris(2-methoxyphenyl)phosphine. Complexes 2-5 have been identified by elemental analyses, spectroscopies, and X-ray crystallography. The electrochemical properties were probed by cyclic voltammetry, which shows that these complexes can catalyze the production of dihydrogen with acetic acid as a proton source. 2 had the lowest overpotential and 4 had the highest catalytic efficiency. Moreover, we have investigated the antifungal activity of these new complexes.
In this paper, four di-iron complexes with an isoxazole moiety were synthesized and characterized. The reaction of a hydroxy-containing di-iron complex [Fe2(CO)6(μ-SCH2CH(CH2OH)S)] (1) with 5-methylisoxazole-4-carboxylic acid gave an ester product, named [Fe2(CO)6(μ-SCH2CHCH2OOC(5-C3HNOCH3)S)] (2) in very good yield. The phosphine-bearing analogues, which are named [Fe2(CO)5(L)(μ-SCH2CHCH2OOC(5-C3HNOCH3)S)] where L= P(4-C6H4CH3)3 (3), P(4-C6H4F)3 (4), P(2-C6H4OCH3)3 (5), were prepared by the reactions of complex 2 with a monophosphine ligand tri(p-tolyl)phosphine, tris(4-fluorophenyl)phosphine or tris(2-methoxyphenyl)phosphine. Complexes 2-5 have been identified by elemental analyses, spectroscopies, and X-ray crystallography. The electrochemical properties were probed by cyclic voltammetry, which shows that these complexes can catalyze the production of dihydrogen with acetic acid as a proton source. 2 had the lowest overpotential and 4 had the highest catalytic efficiency. Moreover, we have investigated the antifungal activity of these new complexes.
2023, 39(12): 2377-2384
doi: 10.11862/CJIC.2023.207
Abstract:
A new cobalt(Ⅱ)-based complex, namely {[Co(Hppc)2][Co2(4, 4′-bipy)(H2O)4](SO4)2•2H2O}n (1) where H2ppc=5-(3-pyridyl)-1H-pyrazole-3-carboxylic acid and 4, 4′-bipy=4, 4′-bipyridine, was synthesized by solvothermal method. The ligand H2ppc is constituted by a pyridine ring, pyrazole ring, and carboxyl group, which possesses rigidity and flexibility. Complex 1 was structurally determined by single-crystal X-ray diffraction and displays that the complex crystallizes in the C2/c pace group, monoclinic system. Complex 1 includes two crystallographic independent parts which are 2D layered [Co(Hppc)2] and 1D chain like [Co2(4, 4′-bipy)(H2O)4]2- forming a co-crystal structure with a {44•62}{4}2 topological network. Furthermore, complex 1 exhibits good electrochemiluminescence (ECL) performance and supercapacitive performance.
A new cobalt(Ⅱ)-based complex, namely {[Co(Hppc)2][Co2(4, 4′-bipy)(H2O)4](SO4)2•2H2O}n (1) where H2ppc=5-(3-pyridyl)-1H-pyrazole-3-carboxylic acid and 4, 4′-bipy=4, 4′-bipyridine, was synthesized by solvothermal method. The ligand H2ppc is constituted by a pyridine ring, pyrazole ring, and carboxyl group, which possesses rigidity and flexibility. Complex 1 was structurally determined by single-crystal X-ray diffraction and displays that the complex crystallizes in the C2/c pace group, monoclinic system. Complex 1 includes two crystallographic independent parts which are 2D layered [Co(Hppc)2] and 1D chain like [Co2(4, 4′-bipy)(H2O)4]2- forming a co-crystal structure with a {44•62}{4}2 topological network. Furthermore, complex 1 exhibits good electrochemiluminescence (ECL) performance and supercapacitive performance.
2023, 39(12): 2385-2392
doi: 10.11862/CJIC.2023.190
Abstract:
Three zinc(Ⅱ), nickel(Ⅱ), and cobalt(Ⅱ) coordination polymers, namely {[Zn(μ3-pdba)(phen)]•H2O}n (1), {[Ni(μ3-pdba)(bipy)]•3H2O}n (2), and {[Co(μ3-pdba)(H2biim)(H2O)]•H2O}n (3) have been constructed hydrothermally using 4, 4′-(pyridin-3, 5-diyl)dibenzoic acid (H2pdba), 1, 10-phenanthroline (phen), 2, 2′-bipyridine (bipy), 2, 2′-biimdazole (H2biim), and zinc, nickel and cobalt chlorides at 160 ℃. The products were isolated as stable crystalline solids and were characterized by IR spectra, elemental analyses, thermogravimetric analyses, and single-crystal X-ray diffraction analyses. Single-crystal X-ray diffraction analyses reveal that the three compounds crystallize in the monoclinic system, space groups P21/c or P21/n. Compounds 1 and 2 show 2D networks. Compound 3 discloses a 1D ladder chain structure. The catalytic activities in the Henry reaction of these compounds were investigated. Compound 1 exhibited an effective catalytic activity in the Henry reaction at 70 ℃. For this reaction, various parameters were optimized, followed by the investigation of the substrate scope.
Three zinc(Ⅱ), nickel(Ⅱ), and cobalt(Ⅱ) coordination polymers, namely {[Zn(μ3-pdba)(phen)]•H2O}n (1), {[Ni(μ3-pdba)(bipy)]•3H2O}n (2), and {[Co(μ3-pdba)(H2biim)(H2O)]•H2O}n (3) have been constructed hydrothermally using 4, 4′-(pyridin-3, 5-diyl)dibenzoic acid (H2pdba), 1, 10-phenanthroline (phen), 2, 2′-bipyridine (bipy), 2, 2′-biimdazole (H2biim), and zinc, nickel and cobalt chlorides at 160 ℃. The products were isolated as stable crystalline solids and were characterized by IR spectra, elemental analyses, thermogravimetric analyses, and single-crystal X-ray diffraction analyses. Single-crystal X-ray diffraction analyses reveal that the three compounds crystallize in the monoclinic system, space groups P21/c or P21/n. Compounds 1 and 2 show 2D networks. Compound 3 discloses a 1D ladder chain structure. The catalytic activities in the Henry reaction of these compounds were investigated. Compound 1 exhibited an effective catalytic activity in the Henry reaction at 70 ℃. For this reaction, various parameters were optimized, followed by the investigation of the substrate scope.
2023, 39(12): 2393-2406
doi: 10.11862/CJIC.2023.200
Abstract:
Two new coordination polymers [Co(L)0.5(1, 3-bib)] (1) and [Ni2(L)(1, 4-bib)3(H2O)2]·2H2O (2), where H4L=1, 2, 4, 5-benzenetetracarboxylic acid, 1, 3-bib=1, 3-bis((1H-imidazol-1-yl)methyl) benzene, and 1, 4-bib=1, 4-bis((1H- imidazol-1-yl)methyl) benzene, were synthesized under hydrothermal conditions. The structures of 1 and 2 were confirmed by elemental analysis, FTIR spectroscopy, single-crystal X-ray diffraction, etc. The results show that 1 and 2 are 3D network structures. The completely deprotonated L4- ligand adopts the μ4-к2∶к1∶к2∶к1 mode in 1 and the μ2-к1∶к0∶к1∶к0 coordination mode in 2. Further studies showed that in the presence of H2O2 and visible light irradiation conditions, 1 had good photocatalytic performance for the degradation of MO (methyl orange)/MB (methylene blue) in water, and the degradation rates reached 83.2% and 84.5% at 180 min. Under the same conditions, 2 also showed good degradation of the dyes MB and RhB (rhodamine B) in aqueous solution, with 87.0% and 77.4% degradation rates at 180 min, respectively. In addition, the mechanism of photocatalytic degradation of the dye by 1 and 2 was investigated.
Two new coordination polymers [Co(L)0.5(1, 3-bib)] (1) and [Ni2(L)(1, 4-bib)3(H2O)2]·2H2O (2), where H4L=1, 2, 4, 5-benzenetetracarboxylic acid, 1, 3-bib=1, 3-bis((1H-imidazol-1-yl)methyl) benzene, and 1, 4-bib=1, 4-bis((1H- imidazol-1-yl)methyl) benzene, were synthesized under hydrothermal conditions. The structures of 1 and 2 were confirmed by elemental analysis, FTIR spectroscopy, single-crystal X-ray diffraction, etc. The results show that 1 and 2 are 3D network structures. The completely deprotonated L4- ligand adopts the μ4-к2∶к1∶к2∶к1 mode in 1 and the μ2-к1∶к0∶к1∶к0 coordination mode in 2. Further studies showed that in the presence of H2O2 and visible light irradiation conditions, 1 had good photocatalytic performance for the degradation of MO (methyl orange)/MB (methylene blue) in water, and the degradation rates reached 83.2% and 84.5% at 180 min. Under the same conditions, 2 also showed good degradation of the dyes MB and RhB (rhodamine B) in aqueous solution, with 87.0% and 77.4% degradation rates at 180 min, respectively. In addition, the mechanism of photocatalytic degradation of the dye by 1 and 2 was investigated.
2023, 39(12): 2407-2414
doi: 10.11862/CJIC.2023.197
Abstract:
A novel Cd(Ⅱ)-based coordination polymer (CP), {[Cd(adc)(dppc)(H2O)]·2H2O}n (1), was synthesized by a solvothermal method based on adamantane-1, 3-dicarboxylic acid (H2adc) and 3, 6-di(pyridin-4-yl)-9-(4-(pyridin-4-yl) phenyl)-9H-carbazole (dppc). Complex 1 belongs to the monoclinic system with space group C2/c, which exhibits a layer structure. The adjacent layers are extended via weak interactions to form a 3D supramolecular structure. Moreover, 1 displayed an excellent photoluminescence property, which can be used as a"turn-off"fluorescence probe to detect 2, 4, 6-trini-trophenol in DMF solution with high selectivity and sensitivity with Ksv of 7.6×104 L·mol-1.
A novel Cd(Ⅱ)-based coordination polymer (CP), {[Cd(adc)(dppc)(H2O)]·2H2O}n (1), was synthesized by a solvothermal method based on adamantane-1, 3-dicarboxylic acid (H2adc) and 3, 6-di(pyridin-4-yl)-9-(4-(pyridin-4-yl) phenyl)-9H-carbazole (dppc). Complex 1 belongs to the monoclinic system with space group C2/c, which exhibits a layer structure. The adjacent layers are extended via weak interactions to form a 3D supramolecular structure. Moreover, 1 displayed an excellent photoluminescence property, which can be used as a"turn-off"fluorescence probe to detect 2, 4, 6-trini-trophenol in DMF solution with high selectivity and sensitivity with Ksv of 7.6×104 L·mol-1.
2023, 39(12): 2415-2424
doi: 10.11862/CJIC.2023.201
Abstract:
A series of nickel and cobalt oxide (NCO) nanosheets were synthesized through a two-step hydrothermal- calcined method. Transition metal ions in NCO nanosheets were adjusted by changing the molar ratios of nickel and cobalt ions in precursor solutions. The crystalline phases, morphologies, and structures of the NCO nanosheets were characterized using X-ray diffraction, scanning electron microscope, and X-ray photoelectron spectroscopy. Furthermore, the electrochemical performances of the NCO nanosheets electrodes were tested. The result indicated that the NCO-2 (Ni1.95Co1Ox) nanosheets exhibited high specific capacitance of 1 096.88 F·g-1 under 0.5 A·g-1, which concurrently possessed a cycling ability of 78.26% after 5 000 cycles. Importantly, the asymmetric supercapacitor, which was constructed from the NCO-2 positive electrode and active carbon negative electrode, presented an energy density of 57.70 Wh·kg-1 at a power density of 576 W·kg-1.
A series of nickel and cobalt oxide (NCO) nanosheets were synthesized through a two-step hydrothermal- calcined method. Transition metal ions in NCO nanosheets were adjusted by changing the molar ratios of nickel and cobalt ions in precursor solutions. The crystalline phases, morphologies, and structures of the NCO nanosheets were characterized using X-ray diffraction, scanning electron microscope, and X-ray photoelectron spectroscopy. Furthermore, the electrochemical performances of the NCO nanosheets electrodes were tested. The result indicated that the NCO-2 (Ni1.95Co1Ox) nanosheets exhibited high specific capacitance of 1 096.88 F·g-1 under 0.5 A·g-1, which concurrently possessed a cycling ability of 78.26% after 5 000 cycles. Importantly, the asymmetric supercapacitor, which was constructed from the NCO-2 positive electrode and active carbon negative electrode, presented an energy density of 57.70 Wh·kg-1 at a power density of 576 W·kg-1.
2023, 39(12): 2425-2431
doi: 10.11862/CJIC.2023.209
Abstract:
Photochromic materials of reversible color change and appropriate photo - generated color lifetime are important for inkless and erasable printing technology. We designed a naphthalene diimide - based (NDI - based) ligand (H2ncm) by combining 1, 4, 5, 8-naphthalenetetracarboxylic dianhydride with methionine and synthesized two coordination polymers from Zn2+ and H2ncm through solvothermal reactions. Compound [Zn(ncm)(H2O)4]·2DMF (1) is composed of one Zn2+ ion, one ncm2- ligand, four coordinated water, and two DMF solvent molecules. The Zn2+ ion is in an octahedral coordination environment and linked by ncm2- ligands into a linear chain. Compound [Zn2(ncm)2(H2O)4] (2) contains two Zn2+ ions, two ncm2- ligands, and four coordinated water molecules. The two Zn2+ ions are bridged by two carboxylate groups into a binuclear Zn2 unit, which are linked by ncm2- ligands into a layer structure.2 showed a photo-induced color change from yellow to dark brown. The photo-induced brown color could be stable for up to three weeks in the air but changed back to yellow within 5 min upon heating at 70 ℃. We showed that this photochromism originates from the generation of NDI· radical upon light irradiation.
Photochromic materials of reversible color change and appropriate photo - generated color lifetime are important for inkless and erasable printing technology. We designed a naphthalene diimide - based (NDI - based) ligand (H2ncm) by combining 1, 4, 5, 8-naphthalenetetracarboxylic dianhydride with methionine and synthesized two coordination polymers from Zn2+ and H2ncm through solvothermal reactions. Compound [Zn(ncm)(H2O)4]·2DMF (1) is composed of one Zn2+ ion, one ncm2- ligand, four coordinated water, and two DMF solvent molecules. The Zn2+ ion is in an octahedral coordination environment and linked by ncm2- ligands into a linear chain. Compound [Zn2(ncm)2(H2O)4] (2) contains two Zn2+ ions, two ncm2- ligands, and four coordinated water molecules. The two Zn2+ ions are bridged by two carboxylate groups into a binuclear Zn2 unit, which are linked by ncm2- ligands into a layer structure.2 showed a photo-induced color change from yellow to dark brown. The photo-induced brown color could be stable for up to three weeks in the air but changed back to yellow within 5 min upon heating at 70 ℃. We showed that this photochromism originates from the generation of NDI· radical upon light irradiation.
2023, 39(12): 2432-2440
doi: 10.11862/CJIC.2023.192
Abstract:
An effective method to prepare β-Co(OH)2/nitrogen-doped carbon graphene (Co(OH)2/C-N@GP) nanocom- posites is presented in this work. First, we synthesized a composite of ZIF-67 and polystyrene by reacting Co(NO3)2·6H2O with 2-methylimidazole in a polystyrene-COOH ethanol dispersion. The ZIF-67/polystyrene composite was carbonized and subsequently reacted with thioacetamide and graphene to produce Co(SO4)2/C-N@GP. Finally, Co(SO4)2/C-N@GP was soaked in KOH aqueous solution to obtain Co(OH)2/C-N@GP nanocomposites. The scanning electron microscope image of obtained Co(OH)2/C-N@GP showed Co(OH)2 with sizes of 10-20 nm well dispersed on the graphene. Electrochemical analysis indicated that Co(OH)2/C-N as an electrode material exhibits typical Faraday charge-transfer behavior for supercapacitors. The specific capacitance of Co(OH)2/C-N can be enhanced when graphene is present. The Co(OH)2/C-N@GP exhibited a high specific capacitance of 985.4 F·g-1 at 2 A·g-1 in 3 mol·L-1 KOH with a specific capacitance retention rate of 76.6% after 1 000 cycles.
An effective method to prepare β-Co(OH)2/nitrogen-doped carbon graphene (Co(OH)2/C-N@GP) nanocom- posites is presented in this work. First, we synthesized a composite of ZIF-67 and polystyrene by reacting Co(NO3)2·6H2O with 2-methylimidazole in a polystyrene-COOH ethanol dispersion. The ZIF-67/polystyrene composite was carbonized and subsequently reacted with thioacetamide and graphene to produce Co(SO4)2/C-N@GP. Finally, Co(SO4)2/C-N@GP was soaked in KOH aqueous solution to obtain Co(OH)2/C-N@GP nanocomposites. The scanning electron microscope image of obtained Co(OH)2/C-N@GP showed Co(OH)2 with sizes of 10-20 nm well dispersed on the graphene. Electrochemical analysis indicated that Co(OH)2/C-N as an electrode material exhibits typical Faraday charge-transfer behavior for supercapacitors. The specific capacitance of Co(OH)2/C-N can be enhanced when graphene is present. The Co(OH)2/C-N@GP exhibited a high specific capacitance of 985.4 F·g-1 at 2 A·g-1 in 3 mol·L-1 KOH with a specific capacitance retention rate of 76.6% after 1 000 cycles.
