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2024 Volume 40 Issue 3
2024, 40(3): 465-480
doi: 10.11862/CJIC.20230306
Abstract:
Polyoxometalates, abbreviated as POMs, are a special kind of versatile nanosized metal-oxygen clusters formed by the assembly of high-valent early transition-metal atoms (typically V5+, Nb5+, Ta5+, Mo6+ and W6+). They have various structures and unique physicochemical properties and are widely used in the fields of catalysis, magnetism, materials science, medicine, and optics. In the past few decades, polyoxoniobates (PONbs), a subfamily of POMs, have drawn considerable attention due to their structural diversity and application prospects in alkaline catalysis and photocatalytic hydrogen production, etc. According to whether they contain heteroatoms or not, PONbs can be classified into two categories, namely, isopolyoxoniobates and heteropolyoxoniobates (HPONbs). In this review, we systematically summarise typical HPONbs with main group elements (ⅢA/ⅣA/ⅤA/ⅥA) or transition metal elements (V/Fe/Cu) as heteroatoms reported in the past several decades, including their assembly methodologies, structure regulation, properties, and related applications. Moreover, the current challenges and prospects of these materials are also discussed. We hope that this review can provide some helpful enlightenment and promising directions for exploring and discovering innovative PONb-based materials with unique functions and practicability.
Polyoxometalates, abbreviated as POMs, are a special kind of versatile nanosized metal-oxygen clusters formed by the assembly of high-valent early transition-metal atoms (typically V5+, Nb5+, Ta5+, Mo6+ and W6+). They have various structures and unique physicochemical properties and are widely used in the fields of catalysis, magnetism, materials science, medicine, and optics. In the past few decades, polyoxoniobates (PONbs), a subfamily of POMs, have drawn considerable attention due to their structural diversity and application prospects in alkaline catalysis and photocatalytic hydrogen production, etc. According to whether they contain heteroatoms or not, PONbs can be classified into two categories, namely, isopolyoxoniobates and heteropolyoxoniobates (HPONbs). In this review, we systematically summarise typical HPONbs with main group elements (ⅢA/ⅣA/ⅤA/ⅥA) or transition metal elements (V/Fe/Cu) as heteroatoms reported in the past several decades, including their assembly methodologies, structure regulation, properties, and related applications. Moreover, the current challenges and prospects of these materials are also discussed. We hope that this review can provide some helpful enlightenment and promising directions for exploring and discovering innovative PONb-based materials with unique functions and practicability.
2024, 40(3): 481-495
doi: 10.11862/CJIC.20230314
Abstract:
A series of MIL-100(Fe)/BiOBr direct Z-scheme heterojunctions was fabricated by the in-situ precipitation method. The crystal structures, micromorphology, optical adsorption property, and chemical states were estimated by powder X-ray diffraction (PXRD), Fourier transforms infrared (FTIR) spectra, UV-Vis diffuse reflectance spectra (UV-Vis DRS), scanning electron microscopy (SEM), high-resolution transmission electron microscope (HRTEM) and X-ray photoelectron spectra (XPS). The performance of photo-Fenton degradation for sulfamethoxazole (SMX) under low-powered light emitting diode lamp irradiation was explored. The catalytic degradation efficiency of SMX (5 mg·L-1) in the optimal reaction system (MB-7/Vis/H2O2, MB-7 was prepared when the mass of MIL-100 (Fe) was 70% of the mass of BiOBr) could reach 99.8% upon 70 min illumination. Meanwhile, the effects of H2O2 concentration, catalyst dosage, pH, and co-existing inorganic anions on SMX removal over MB-7/Vis/H2O2 were studied. The removal efficiency of SMX could reach above 95% after five consecutive operations, suggesting that MB-7 had good stability and reusability. The possible catalytic mechanism was unraveled by photoluminescence (PL) spectra, electrochemical measurements, radical trapping experiments, and electronic spin resonance (ESR) technique. The enhanced photo-Fenton reactivity could be attributed to the fabrication of heterostructures accelerated separation photocarriers and then induced the generation of reactive species and Fe3+/Fe2+ redox cycle.
A series of MIL-100(Fe)/BiOBr direct Z-scheme heterojunctions was fabricated by the in-situ precipitation method. The crystal structures, micromorphology, optical adsorption property, and chemical states were estimated by powder X-ray diffraction (PXRD), Fourier transforms infrared (FTIR) spectra, UV-Vis diffuse reflectance spectra (UV-Vis DRS), scanning electron microscopy (SEM), high-resolution transmission electron microscope (HRTEM) and X-ray photoelectron spectra (XPS). The performance of photo-Fenton degradation for sulfamethoxazole (SMX) under low-powered light emitting diode lamp irradiation was explored. The catalytic degradation efficiency of SMX (5 mg·L-1) in the optimal reaction system (MB-7/Vis/H2O2, MB-7 was prepared when the mass of MIL-100 (Fe) was 70% of the mass of BiOBr) could reach 99.8% upon 70 min illumination. Meanwhile, the effects of H2O2 concentration, catalyst dosage, pH, and co-existing inorganic anions on SMX removal over MB-7/Vis/H2O2 were studied. The removal efficiency of SMX could reach above 95% after five consecutive operations, suggesting that MB-7 had good stability and reusability. The possible catalytic mechanism was unraveled by photoluminescence (PL) spectra, electrochemical measurements, radical trapping experiments, and electronic spin resonance (ESR) technique. The enhanced photo-Fenton reactivity could be attributed to the fabrication of heterostructures accelerated separation photocarriers and then induced the generation of reactive species and Fe3+/Fe2+ redox cycle.
2024, 40(3): 496-506
doi: 10.11862/CJIC.20230317
Abstract:
In this study, a composite of Cu-Cu2O/UiO-66-NH2 based on a metal-organic framework (MOF) was successfully prepared by solvothermal method, and it was comprehensively characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The effects of solvent, temperature, and catalyst loading on the oxidation of benzyl alcohol to benzaldehyde were investigated using air as an oxidant. The composite catalyst showed excellent catalytic performance, and benzyl alcohol could be quantitatively converted to benzaldehyde at 60 ℃ for 5 h. Additionally, other alcohol substrates such as benzylic alcohols, allylic alcohols, and heteroaryl alcohols, were selectively transformed into the corresponding aldehydes in excellent yields. Notably, the activity of the catalyst was almost unchanged after three cycles of recycling, demonstrating good stability and reusability.
In this study, a composite of Cu-Cu2O/UiO-66-NH2 based on a metal-organic framework (MOF) was successfully prepared by solvothermal method, and it was comprehensively characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The effects of solvent, temperature, and catalyst loading on the oxidation of benzyl alcohol to benzaldehyde were investigated using air as an oxidant. The composite catalyst showed excellent catalytic performance, and benzyl alcohol could be quantitatively converted to benzaldehyde at 60 ℃ for 5 h. Additionally, other alcohol substrates such as benzylic alcohols, allylic alcohols, and heteroaryl alcohols, were selectively transformed into the corresponding aldehydes in excellent yields. Notably, the activity of the catalyst was almost unchanged after three cycles of recycling, demonstrating good stability and reusability.
2024, 40(3): 507-514
doi: 10.11862/CJIC.20230403
Abstract:
Ultra-thin and b-axis oriented MFI zeolite membranes were fabricated by a vapor phase transport (VPT) method using ethylenediamine-water vapor. The membrane thickness was rationally controlled by converting a deposit layer of MFI nanosheets into a dense zeolite membrane. Scanning electron microscope and X-ray diffraction results revealed that the prepared membrane had a thickness of about 280 nm with a highly b-axis oriented dense structure. The binary gas separation test of butane isomers showed that a permeation rate of n-butane of 1.5×10-7 mol·m-2·s-1·Pa-1 at a separation factor of 14.8 could be achieved for an equimolar n-butane/iso-butane mixtures at 333 K. Na2SiO3, serving as a source of silica and alkalinity, played a crucial role in the secondary growth of MFI zeolite nanosheets. Na2SiO3 facilitated the fusion growth among the MFI zeolite nanosheets in the presence of amine vapor, which improved the orientation and compactness of the membranes.
Ultra-thin and b-axis oriented MFI zeolite membranes were fabricated by a vapor phase transport (VPT) method using ethylenediamine-water vapor. The membrane thickness was rationally controlled by converting a deposit layer of MFI nanosheets into a dense zeolite membrane. Scanning electron microscope and X-ray diffraction results revealed that the prepared membrane had a thickness of about 280 nm with a highly b-axis oriented dense structure. The binary gas separation test of butane isomers showed that a permeation rate of n-butane of 1.5×10-7 mol·m-2·s-1·Pa-1 at a separation factor of 14.8 could be achieved for an equimolar n-butane/iso-butane mixtures at 333 K. Na2SiO3, serving as a source of silica and alkalinity, played a crucial role in the secondary growth of MFI zeolite nanosheets. Na2SiO3 facilitated the fusion growth among the MFI zeolite nanosheets in the presence of amine vapor, which improved the orientation and compactness of the membranes.
2024, 40(3): 515-522
doi: 10.11862/CJIC.20230385
Abstract:
In this study, a combination of grand canonical Monte Carlo and density functional theory was employed to investigate the CO2 adsorption and separation behavior of naphyne (NY) and naphdiyne (NDY) with different alkali metal (AM, including Li, Na, and K) dopants. By analyzing the binding energy, cohesive energy, and electronic properties, it is found that AM-modified NY and NDY exhibit good structural stability. Under conditions of 298 K and 100 kPa, Li-NDY (the NDY modified by Li), exhibits a CO2 adsorption capacity of 11.37 mmol·g-1, with a selectivity for CO2 over N2 of 430.85. Furthermore, the gas adsorption density distribution elucidates the reasons behind the high adsorption capacity of AM-NY and AM-NDY and the inherent difference in their performance. Finally, the modified mechanisms introduced by the AM dopants were discussed in detail from the perspectives of adsorption heat, Coulomb and van der Waals interactions, and other factors.
In this study, a combination of grand canonical Monte Carlo and density functional theory was employed to investigate the CO2 adsorption and separation behavior of naphyne (NY) and naphdiyne (NDY) with different alkali metal (AM, including Li, Na, and K) dopants. By analyzing the binding energy, cohesive energy, and electronic properties, it is found that AM-modified NY and NDY exhibit good structural stability. Under conditions of 298 K and 100 kPa, Li-NDY (the NDY modified by Li), exhibits a CO2 adsorption capacity of 11.37 mmol·g-1, with a selectivity for CO2 over N2 of 430.85. Furthermore, the gas adsorption density distribution elucidates the reasons behind the high adsorption capacity of AM-NY and AM-NDY and the inherent difference in their performance. Finally, the modified mechanisms introduced by the AM dopants were discussed in detail from the perspectives of adsorption heat, Coulomb and van der Waals interactions, and other factors.
2024, 40(3): 523-532
doi: 10.11862/CJIC.20230349
Abstract:
Zr-based metal-organic framework (MOF) NH2-UiO-66 was first synthesized by a solvothermal method using 2-amino terephthalic acid (H2ATA) as the ligand. The efficient W18O49/NH2-UiO-66 photocatalysts with a typical type Ⅱ heterojunction were then constructed by in-situ growth of the oxygen vacancy-rich defective tungsten oxide (W18O49) on NH2-UiO-66, using tungsten chloride as the precursor. The composition and structure of the catalysts were characterized by a series of measurements, including powder X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and UV-Vis diffuse reflectance spectroscopy. At room temperature and atmospheric pressure, the photoactivity of all the catalysts was examined under simulated sunlight with styrene oxide as the model substrate. W18O49/NH2-UiO-66 exhibited the highest yield of styrene carbonate (58 mmol·g-1·h-1). The introduction of NH2-UiO-66 expanded the specific surface area, CO2 adsorption capacity, light harvesting ability, and photogenerated charge carriers transfer of W18O49.
Zr-based metal-organic framework (MOF) NH2-UiO-66 was first synthesized by a solvothermal method using 2-amino terephthalic acid (H2ATA) as the ligand. The efficient W18O49/NH2-UiO-66 photocatalysts with a typical type Ⅱ heterojunction were then constructed by in-situ growth of the oxygen vacancy-rich defective tungsten oxide (W18O49) on NH2-UiO-66, using tungsten chloride as the precursor. The composition and structure of the catalysts were characterized by a series of measurements, including powder X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and UV-Vis diffuse reflectance spectroscopy. At room temperature and atmospheric pressure, the photoactivity of all the catalysts was examined under simulated sunlight with styrene oxide as the model substrate. W18O49/NH2-UiO-66 exhibited the highest yield of styrene carbonate (58 mmol·g-1·h-1). The introduction of NH2-UiO-66 expanded the specific surface area, CO2 adsorption capacity, light harvesting ability, and photogenerated charge carriers transfer of W18O49.
2024, 40(3): 533-543
doi: 10.11862/CJIC.20230312
Abstract:
Through alkali treatment, the pore structure of diatomite (DIA) was optimized, the porosity was increased, and the paraffin loading was increased. A novel paraffin/alkali-modified DIA/expanded graphite (EG-alDIAP) composite with stable properties was prepared by direct impregnation method. The relationship between structure and properties of the material was studied. The results showed that the paraffin loading of the composite phase change material increased from 47.4% to 61.1%, thereby improving the heat storage performance of the composite material. The addition of expanded graphite (EG) to the modified diatomite improved the heat transfer capacity of the composite material. The addition of mass fraction of 10% EG increased the thermal conductivity by 113% (from 0.276 to 0.589 W·m-1·K-1). With the increase of EG content, the latent heat of the composite phase change material increased slightly, but the chemical compatibility and stability did not change significantly. The paraffin/alkali-modified DIA composite containing 10% expanded graphite had reliable energy storage, good temperature regulation performance and heat storage and release capacity.
Through alkali treatment, the pore structure of diatomite (DIA) was optimized, the porosity was increased, and the paraffin loading was increased. A novel paraffin/alkali-modified DIA/expanded graphite (EG-alDIAP) composite with stable properties was prepared by direct impregnation method. The relationship between structure and properties of the material was studied. The results showed that the paraffin loading of the composite phase change material increased from 47.4% to 61.1%, thereby improving the heat storage performance of the composite material. The addition of expanded graphite (EG) to the modified diatomite improved the heat transfer capacity of the composite material. The addition of mass fraction of 10% EG increased the thermal conductivity by 113% (from 0.276 to 0.589 W·m-1·K-1). With the increase of EG content, the latent heat of the composite phase change material increased slightly, but the chemical compatibility and stability did not change significantly. The paraffin/alkali-modified DIA composite containing 10% expanded graphite had reliable energy storage, good temperature regulation performance and heat storage and release capacity.
2024, 40(3): 544-554
doi: 10.11862/CJIC.20230239
Abstract:
A magnetic composite material (Fe3O4@PAA@ZIF-8) was designed and synthesized with magnetic nanoparticles as the nucleus, polymer as the intermediate layer, and zeolitic imidazolate framework-8 (ZIF-8) as the outer layer. First, Fe3O4 nanoparticles were prepared by solvothermal method, and then polyacrylic acid (PAA) layer was coated on the surface of Fe3O4 nanoparticles by distillation precipitation polymerization, and finally ZIF-8 was coated on the surface of the Fe3O4@PAA by in-situ deposition method (composite method). Based on the characterization of the composition, structure and morphology of Fe3O4@PAA@ZIF-8, the adsorption properties of malachite green (MG) were studied in depth. Transmission electron microscope (TEM) showed that Fe3O4@PAA@ZIF-8 had a distinct three-layer structure, with an average particle size of 117 nm for Fe3O4, a thickness of about 17 nm for the PAA layer, and a thickness of about 14 nm for the ZIF-8 layer. The adsorption capacity of Fe3O4@PAA@ZIF-8 for MG increased with the increase of pH, and the adsorption process conformed to the quasi-second-order kinetic model and the Langmuir isothermal model, and the maximum adsorption capacity could reach 9 759 mg·g-1. In addition, Fe3O4@PAA@ZIF-8 had good reusability, and the maximum adsorption capacity of MG (500 mg·L-1) could still reach 982 mg·g-1 after 8 cycles.
A magnetic composite material (Fe3O4@PAA@ZIF-8) was designed and synthesized with magnetic nanoparticles as the nucleus, polymer as the intermediate layer, and zeolitic imidazolate framework-8 (ZIF-8) as the outer layer. First, Fe3O4 nanoparticles were prepared by solvothermal method, and then polyacrylic acid (PAA) layer was coated on the surface of Fe3O4 nanoparticles by distillation precipitation polymerization, and finally ZIF-8 was coated on the surface of the Fe3O4@PAA by in-situ deposition method (composite method). Based on the characterization of the composition, structure and morphology of Fe3O4@PAA@ZIF-8, the adsorption properties of malachite green (MG) were studied in depth. Transmission electron microscope (TEM) showed that Fe3O4@PAA@ZIF-8 had a distinct three-layer structure, with an average particle size of 117 nm for Fe3O4, a thickness of about 17 nm for the PAA layer, and a thickness of about 14 nm for the ZIF-8 layer. The adsorption capacity of Fe3O4@PAA@ZIF-8 for MG increased with the increase of pH, and the adsorption process conformed to the quasi-second-order kinetic model and the Langmuir isothermal model, and the maximum adsorption capacity could reach 9 759 mg·g-1. In addition, Fe3O4@PAA@ZIF-8 had good reusability, and the maximum adsorption capacity of MG (500 mg·L-1) could still reach 982 mg·g-1 after 8 cycles.
2024, 40(3): 555-560
doi: 10.11862/CJIC.20230282
Abstract:
The electronic and optical properties of the Cs3Bi2X9 (X=Cl, Br, I) was emphatically explored theoretically by density functional theory methods based on first principles, and the influence of interference effect on the these three crystals is systematically elucidated. Our results reveal that the optical properties of the three materials are dominated by the valence electrons in p-orbitals of the Bi and halogen atoms. In the visible region, the absorption peaks have a red shift with increase of atomic number of halogen increases. The optical absorption is special and very sensitive to the interference structure on one-dimensional Cs3Bi2Cl9, but not to that of two-dimensional Cs3Bi2Br9 and zero-dimensional Cs3Bi2I9. The thickness of the Cs3Bi2Br9 film also influences the optical properties. While the zero-dimensional Cs3Bi2I9 is almost unaffected by crystal thickness and surface characteristic.
The electronic and optical properties of the Cs3Bi2X9 (X=Cl, Br, I) was emphatically explored theoretically by density functional theory methods based on first principles, and the influence of interference effect on the these three crystals is systematically elucidated. Our results reveal that the optical properties of the three materials are dominated by the valence electrons in p-orbitals of the Bi and halogen atoms. In the visible region, the absorption peaks have a red shift with increase of atomic number of halogen increases. The optical absorption is special and very sensitive to the interference structure on one-dimensional Cs3Bi2Cl9, but not to that of two-dimensional Cs3Bi2Br9 and zero-dimensional Cs3Bi2I9. The thickness of the Cs3Bi2Br9 film also influences the optical properties. While the zero-dimensional Cs3Bi2I9 is almost unaffected by crystal thickness and surface characteristic.
2024, 40(3): 561-570
doi: 10.11862/CJIC.20230276
Abstract:
The Ni-La/Al2O3 catalysts derived from hydrotalcite were prepared by an in-situ growth method and applied in CO2 methanation to investigate the influence of La doping amount on the morphology, structure, and catalytic performance of the catalysts. The morphology and structure of the obtained catalysts were analyzed by inductively-coupled plasma emission spectroscopy, X-ray diffraction, H2 temperature programmed reduction, low-temperature N2 adsorption-desorption, scanning electron microscopy, and transmission electron microscopy, respectively. The characterization results indicated that an appropriate amount of La doping could improve the dispersion of active metal Ni on the support, weaken the interaction between Ni and the support, improve the pore structure of the catalyst, and increase the specific surface area of the catalyst. The results of CO2 methanation showed that the catalyst 30Ni-10La/Al2O3 with the Ni loading (mass fraction) of 30% and La doping of 10% possessed the outstanding catalytic performance, which exhibited the CO2 conversion of 91.9% and CH4 yield of 91.5% under 350℃. Moreover, the catalyst 30Ni-10La/Al2O3 remained highly active after the stability test of 60 h.
The Ni-La/Al2O3 catalysts derived from hydrotalcite were prepared by an in-situ growth method and applied in CO2 methanation to investigate the influence of La doping amount on the morphology, structure, and catalytic performance of the catalysts. The morphology and structure of the obtained catalysts were analyzed by inductively-coupled plasma emission spectroscopy, X-ray diffraction, H2 temperature programmed reduction, low-temperature N2 adsorption-desorption, scanning electron microscopy, and transmission electron microscopy, respectively. The characterization results indicated that an appropriate amount of La doping could improve the dispersion of active metal Ni on the support, weaken the interaction between Ni and the support, improve the pore structure of the catalyst, and increase the specific surface area of the catalyst. The results of CO2 methanation showed that the catalyst 30Ni-10La/Al2O3 with the Ni loading (mass fraction) of 30% and La doping of 10% possessed the outstanding catalytic performance, which exhibited the CO2 conversion of 91.9% and CH4 yield of 91.5% under 350℃. Moreover, the catalyst 30Ni-10La/Al2O3 remained highly active after the stability test of 60 h.
2024, 40(3): 571-580
doi: 10.11862/CJIC.20230259
Abstract:
Low-concentration gradient-modified samples of LiCoO2 were prepared by sintering at 1 050℃ using high-temperature solid-phase method, and were coated with LiF doping (LCOLF, LCO@LF) and MgF2 doping (LCOMF, LCO@MF). The material morphologies and electrochemical properties were compared and analyzed utilizing characterization tests such as X-ray photoelectron spectroscopy, transmission electron microscopy, and electrochemical techniques. The results show that in bulk-doping composite electrodes, the thermogravimetric test demonstrated that LCOLF had optimal thermal stability. In LCOMF crystals, crystal plane spacing of (003) and (104) contracted; after 70 cycles at 1C rate under 45℃, the specific capacities of LCOLF and LCOMF were 141.45 and 166.98 mAh·g-1 respectively, and their cycling performance was superior to that of the LiCoO2. In the surface-coated composite electrodes, LCO@LF and LCO@MF grains had clean surfaces and the bond valence of lattice oxygen was enhanced toward higher binding energy; LCO@MF built a solid and compact coating layer, and the specific capacity and capacity retention after 70 cycles were 183 mAh·g-1 and 91.26% (that of LCO@LF were respectively 154.38 mAh·g-1 and 77.54%). The cycling performance of surface-coated composite electrodes was significantly better than that of bulk-doping composite electrodes.
Low-concentration gradient-modified samples of LiCoO2 were prepared by sintering at 1 050℃ using high-temperature solid-phase method, and were coated with LiF doping (LCOLF, LCO@LF) and MgF2 doping (LCOMF, LCO@MF). The material morphologies and electrochemical properties were compared and analyzed utilizing characterization tests such as X-ray photoelectron spectroscopy, transmission electron microscopy, and electrochemical techniques. The results show that in bulk-doping composite electrodes, the thermogravimetric test demonstrated that LCOLF had optimal thermal stability. In LCOMF crystals, crystal plane spacing of (003) and (104) contracted; after 70 cycles at 1C rate under 45℃, the specific capacities of LCOLF and LCOMF were 141.45 and 166.98 mAh·g-1 respectively, and their cycling performance was superior to that of the LiCoO2. In the surface-coated composite electrodes, LCO@LF and LCO@MF grains had clean surfaces and the bond valence of lattice oxygen was enhanced toward higher binding energy; LCO@MF built a solid and compact coating layer, and the specific capacity and capacity retention after 70 cycles were 183 mAh·g-1 and 91.26% (that of LCO@LF were respectively 154.38 mAh·g-1 and 77.54%). The cycling performance of surface-coated composite electrodes was significantly better than that of bulk-doping composite electrodes.
2024, 40(3): 581-590
doi: 10.11862/CJIC.20230253
Abstract:
Using nickel foam as a substrate, NiMoO4 active materials with sheet-like structures were produced in situ, and later NiMoO4/NiMoS4 composites were prepared by vulcanization. On the morphology and electrochemical characteristics of the materials, the impacts of hydrothermal time and thiourea addition were examined. Electrochemical experiments revealed that the NiMoO4/NiMoS4 electrode could release a specific capacitance of 1 560.7 F·g-1 at a current density of 1 A·g-1, and the capacity remained at 76.7% of the initial specific capacitance after 2 000 cycles at a current density of 40 A·g-1. The asymmetric supercapacitors (ASC) device assembled with NiMoO4/NiMoS4 electrode material and activated carbon (AC) as positive and negative electrodes respectively can provide 29.0 Wh·kg-1 energy density at a power density of 400 W·kg-1.
Using nickel foam as a substrate, NiMoO4 active materials with sheet-like structures were produced in situ, and later NiMoO4/NiMoS4 composites were prepared by vulcanization. On the morphology and electrochemical characteristics of the materials, the impacts of hydrothermal time and thiourea addition were examined. Electrochemical experiments revealed that the NiMoO4/NiMoS4 electrode could release a specific capacitance of 1 560.7 F·g-1 at a current density of 1 A·g-1, and the capacity remained at 76.7% of the initial specific capacitance after 2 000 cycles at a current density of 40 A·g-1. The asymmetric supercapacitors (ASC) device assembled with NiMoO4/NiMoS4 electrode material and activated carbon (AC) as positive and negative electrodes respectively can provide 29.0 Wh·kg-1 energy density at a power density of 400 W·kg-1.
2024, 40(3): 591-600
doi: 10.11862/CJIC.20230225
Abstract:
A simple immersion method was used for surface W doping of BiVO4 photoanode. Ciprofloxacin (CIP) was used as a pharmaceuticals and personal care products (PPCPs) model contaminant to study the surface state behavior of W-BiVO4 photoanode for CIP degradation. The results show that low concentration of W doping has no significant effect on the crystal structure, surface morphology and optical absorption performance of BiVO4 photoanode. However, W doping replaces V5+ on the surface of BiVO4 photoanode, inhibiting the V5+/V4+ reduction process on the surface of BiVO4 photoanode and reducing the surface state acting as recombination centre. It can also introduce more oxygen vacancies and increase the surface state acting as reaction sites. CIP degradation reaction is controlled by surface active sites. Surface W doping can effectively promote the charge transfer for CIP degradation, thereby improving the photoelectrocatalytic degradation performance of BiVO4 photoanode.
A simple immersion method was used for surface W doping of BiVO4 photoanode. Ciprofloxacin (CIP) was used as a pharmaceuticals and personal care products (PPCPs) model contaminant to study the surface state behavior of W-BiVO4 photoanode for CIP degradation. The results show that low concentration of W doping has no significant effect on the crystal structure, surface morphology and optical absorption performance of BiVO4 photoanode. However, W doping replaces V5+ on the surface of BiVO4 photoanode, inhibiting the V5+/V4+ reduction process on the surface of BiVO4 photoanode and reducing the surface state acting as recombination centre. It can also introduce more oxygen vacancies and increase the surface state acting as reaction sites. CIP degradation reaction is controlled by surface active sites. Surface W doping can effectively promote the charge transfer for CIP degradation, thereby improving the photoelectrocatalytic degradation performance of BiVO4 photoanode.
2024, 40(3): 601-612
doi: 10.11862/CJIC.20230401
Abstract:
Polyhedral bismuth vanadate (BVO) material was prepared using a straightforward hydrothermal method, and then a small-sized AgNi bimetallic co-catalyst was synthesized in situ on the surface of the polyhedral BVO through a chemical reduction method. The photocatalytic performance of the catalyst was studied. The physicochemical properties of the prepared AgNi/BVO material were characterized through various techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) spectroscopy, and nitrogen adsorption-desorption analysis. The results indicated that AgNi bimetallic co-catalysts were extensively loaded onto the unique morphology of BVO polyhedra, significantly increasing the metal attachment sites. Simultaneously, the AgNi loading also improved the crystallinity of BVO. The silver surface plasmon resonance effect, in conjunction with the nickel's lattice interface effect, enhanced the BVO catalyst's absorption of visible light and improved the separation of photo-generated electrons, thereby increasing the photocatalytic activity. Photocatalytic degradation experiments using MB (methylene blue) as a model pollutant demonstrated that when the ratio was 3:1, AgNi/BVO exhibited the highest catalytic activity, with a reaction rate of 5.4 times higher than that of BVO under visible light irradiation. This photocatalyst retained excellent photocatalytic activity even after four cycles of use.
Polyhedral bismuth vanadate (BVO) material was prepared using a straightforward hydrothermal method, and then a small-sized AgNi bimetallic co-catalyst was synthesized in situ on the surface of the polyhedral BVO through a chemical reduction method. The photocatalytic performance of the catalyst was studied. The physicochemical properties of the prepared AgNi/BVO material were characterized through various techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) spectroscopy, and nitrogen adsorption-desorption analysis. The results indicated that AgNi bimetallic co-catalysts were extensively loaded onto the unique morphology of BVO polyhedra, significantly increasing the metal attachment sites. Simultaneously, the AgNi loading also improved the crystallinity of BVO. The silver surface plasmon resonance effect, in conjunction with the nickel's lattice interface effect, enhanced the BVO catalyst's absorption of visible light and improved the separation of photo-generated electrons, thereby increasing the photocatalytic activity. Photocatalytic degradation experiments using MB (methylene blue) as a model pollutant demonstrated that when the ratio was 3:1, AgNi/BVO exhibited the highest catalytic activity, with a reaction rate of 5.4 times higher than that of BVO under visible light irradiation. This photocatalyst retained excellent photocatalytic activity even after four cycles of use.
2024, 40(3): 613-620
doi: 10.11862/CJIC.20230368
Abstract:
Based on Ⅴ-shaped auxiliary ligands, two novel coordination polymers, {[Cd(bipmo)(NDC)]·1.75H2O}n (1), {[Cd(bppmo)(NDC)(H2O)]·H2O}n (2), where H2NDC=2,6-naphthalenedicarboxylic acid, bipmo=bis(4-(1H-imidazol-1-yl)phenyl)methanone, bppmo=bis(4-(pyridin-4-yl)phenyl)methanone, have been synthesized under solvothermal conditions. They have been characterized by single-crystal X-ray diffraction, bond valence sum calculations, IR spectra, and elemental analyses. Complex 1 shows 2-fold interpenetrating sheets of {63} topology, which interpenetrate in a 2D → 2D parallel manner. Complex 2 reveals a 3-fold interpenetrating {63} network. The results indicate that the Ⅴ-shaped ligands have a great effect on the formation of the final structures. In addition, the luminescent properties of complexes 1 and 2 were investigated in detail.
Based on Ⅴ-shaped auxiliary ligands, two novel coordination polymers, {[Cd(bipmo)(NDC)]·1.75H2O}n (1), {[Cd(bppmo)(NDC)(H2O)]·H2O}n (2), where H2NDC=2,6-naphthalenedicarboxylic acid, bipmo=bis(4-(1H-imidazol-1-yl)phenyl)methanone, bppmo=bis(4-(pyridin-4-yl)phenyl)methanone, have been synthesized under solvothermal conditions. They have been characterized by single-crystal X-ray diffraction, bond valence sum calculations, IR spectra, and elemental analyses. Complex 1 shows 2-fold interpenetrating sheets of {63} topology, which interpenetrate in a 2D → 2D parallel manner. Complex 2 reveals a 3-fold interpenetrating {63} network. The results indicate that the Ⅴ-shaped ligands have a great effect on the formation of the final structures. In addition, the luminescent properties of complexes 1 and 2 were investigated in detail.
2024, 40(3): 621-628
doi: 10.11862/CJIC.20230342
Abstract:
Two nickel(Ⅱ) and zinc(Ⅱ) coordination polymers, namely {[Ni(μ3-cpna)(μ-dpea)0.5]·H2O}n (1) and {[Zn(μ3-cpna)(μ-dpey)0.5]·H2O}n (2) have been constructed hydrothermally using 5-(2-carboxyphenyl)nicotinic acid (H2cpna), 1, 2-di(4-pyridyl)ethane (dpea), 1, 2-di(4-pyridyl)ethylene (dpey), and nickel and zinc 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 revealed that two compounds crystallize in the monoclinic or orthorhombic systems, space groups, P21/c or Pbca. Both compounds show 3D metal-organic frameworks. Compound 2 exhibited an effective catalytic activity in the Knoevenagel condensation reaction at room temperature. Meanwhile, compound 2 showed an effective anti-wear performance in poly-α-olefine synthetic lubricant.
Two nickel(Ⅱ) and zinc(Ⅱ) coordination polymers, namely {[Ni(μ3-cpna)(μ-dpea)0.5]·H2O}n (1) and {[Zn(μ3-cpna)(μ-dpey)0.5]·H2O}n (2) have been constructed hydrothermally using 5-(2-carboxyphenyl)nicotinic acid (H2cpna), 1, 2-di(4-pyridyl)ethane (dpea), 1, 2-di(4-pyridyl)ethylene (dpey), and nickel and zinc 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 revealed that two compounds crystallize in the monoclinic or orthorhombic systems, space groups, P21/c or Pbca. Both compounds show 3D metal-organic frameworks. Compound 2 exhibited an effective catalytic activity in the Knoevenagel condensation reaction at room temperature. Meanwhile, compound 2 showed an effective anti-wear performance in poly-α-olefine synthetic lubricant.
2024, 40(3): 629-645
doi: 10.11862/CJIC.20230315
Abstract:
Impregnation and co-precipitation methods were used to synthesize HoCeMn/TiO2 catalysts for the reduction of NOx with NH3. Different kinds of characterization methods were used to explore the structures and performances of the catalysts. The results show that the co-precipitation method enhances the interactivity between the active component and carrier, thereby increasing the content of Ce3+, Mn4+, and adsorption oxygen on the surface of HoCeMnTi-C. As a result, it showed excellent low-temperature redox performance. In addition, HoCeMnTi-C prepared by the co-precipitation method possessed more surface acidic sites and stronger surface acidity. The improvement of surface acidity and redox performance is conducive to the adsorption and activation of ammonia, and thereby significantly improved its activity. The increase of acidic sites also restrained the adsorption of H2O and SO2, and therefore sulfur and water resistance of HoCeMnTi-C were significantly promoted. The reaction of selective catalytic reduction (SCR) on catalysts obeys the Eley-Rideal (E-R) mechanism. SO2 poisoning of catalysts was caused by the formation of sulfates, which cover or damage the active sites of the catalysts.
Impregnation and co-precipitation methods were used to synthesize HoCeMn/TiO2 catalysts for the reduction of NOx with NH3. Different kinds of characterization methods were used to explore the structures and performances of the catalysts. The results show that the co-precipitation method enhances the interactivity between the active component and carrier, thereby increasing the content of Ce3+, Mn4+, and adsorption oxygen on the surface of HoCeMnTi-C. As a result, it showed excellent low-temperature redox performance. In addition, HoCeMnTi-C prepared by the co-precipitation method possessed more surface acidic sites and stronger surface acidity. The improvement of surface acidity and redox performance is conducive to the adsorption and activation of ammonia, and thereby significantly improved its activity. The increase of acidic sites also restrained the adsorption of H2O and SO2, and therefore sulfur and water resistance of HoCeMnTi-C were significantly promoted. The reaction of selective catalytic reduction (SCR) on catalysts obeys the Eley-Rideal (E-R) mechanism. SO2 poisoning of catalysts was caused by the formation of sulfates, which cover or damage the active sites of the catalysts.
2024, 40(3): 646-654
doi: 10.11862/CJIC.20230291
Abstract:
A new metal-organic framework (MOF) {[Cd(L)0.5(4, 4'-bpy)0.5]·H2O}n (1), where H4L=(1, 1': 4', 1″-terphenyl)-2, 2″, 4, 4″-tetracarboxylic acid, 4, 4'-bpy=4, 4'-bipyridine, was synthesized by hydro-solvothermal method. The structure of complex 1 was characterized by single-crystal X-ray diffraction, elemental analysis, powder X-ray diffraction, thermogravimetric analysis, and infrared spectrum analysis. The analysis of single crystal structure shows that 1 is a 3D structure, belonging to the monoclinic crystal system, C2/c space group. Cd(Ⅱ) connects L4- and 4, 4'-bpy to form a 2D plane structure, and the layers are connected by L4- to form a 3D network structure. The MOF shows good stability and can be used for the detection of tetracycline (TET) and p-nitrophenol (4-NP) by fluorescence quenching. The detection limits of TET and 4-NP were 0.15 and 0.062 μmol·L-1, respectively. In addition, the fluorescence quenching mechanism of 1 was also studied. 1 can be successfully applied to the determination of TET and 4-NP content in Yanhe water samples.
A new metal-organic framework (MOF) {[Cd(L)0.5(4, 4'-bpy)0.5]·H2O}n (1), where H4L=(1, 1': 4', 1″-terphenyl)-2, 2″, 4, 4″-tetracarboxylic acid, 4, 4'-bpy=4, 4'-bipyridine, was synthesized by hydro-solvothermal method. The structure of complex 1 was characterized by single-crystal X-ray diffraction, elemental analysis, powder X-ray diffraction, thermogravimetric analysis, and infrared spectrum analysis. The analysis of single crystal structure shows that 1 is a 3D structure, belonging to the monoclinic crystal system, C2/c space group. Cd(Ⅱ) connects L4- and 4, 4'-bpy to form a 2D plane structure, and the layers are connected by L4- to form a 3D network structure. The MOF shows good stability and can be used for the detection of tetracycline (TET) and p-nitrophenol (4-NP) by fluorescence quenching. The detection limits of TET and 4-NP were 0.15 and 0.062 μmol·L-1, respectively. In addition, the fluorescence quenching mechanism of 1 was also studied. 1 can be successfully applied to the determination of TET and 4-NP content in Yanhe water samples.
