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2023 Volume 38 Issue 2
2023, 39(2): 193-201
doi: 10.11862/CJIC.2022.291
Abstract:
By the introduction of protonated 1, 3-di(4-pyridyl)propane (1, 3-dppH22+) and protonated bis(imidazol-1- ylmethyl)benzene (1, 4-bixH22+) as a cationic template, three new cobalt naphthalene-diphosphate coordination poly- mers based on 1, 4-naphthalenediphosphonic acid (1, 4-ndpaH4), namely (1, 3-dppH2)2[Co4(1, 4-ndpa)(1, 4-ndpaH)2(1, 4-ndpaH2)]·6H2O (1), (1, 4-bixH2)0.5[Co(1, 4-ndpaH)] (2), and (1, 4-bixH2)0.5[Co2(1, 4-ndpaH)(1, 4-ndpaH2)(H2O)2] (3), have been hydrothermally synthesized. Complexes 1-3 were characterized by elemental analysis, infrared spectros- copy, single crystal X -ray diffraction, powder X -ray diffraction, and thermogravimetric analysis, respectively. In complexes 1 and 2, inorganic chains of corner-sharing {CoO4} and {PO3C} tetrahedron are cross-linked by naphtha- lene ligands into 3D open-framework structures. The protonated di-pyridinium/imidazolium moieties, 1, 3-dppH22+ for 2 and 1, 4-bixH22+ for 2, lie inside the skeletal voids of the crystal structure, respectively. Interestingly, complex 3 with similar chemical composition to 2 except for an additional 1, 4-ndpaH22- ligand and two coordinated water mole- cules shows a 2D undulating layer structure, where the chains of corner-sharing {CoO5} trigonal bipyramid, {CoO6} octahedron, and {PO3C} tetrahedron are cross - linked by naphthalene groups. Adjacent layers are packed in AB stacking into the supramolecular structure, in which 1, 4-bixH22+ ions fill and balance the charge of 3. Magnetic stud- ies reveal that dominant antiferromagnetic interactions between the magnetic centers are propagated in complexes 1 and 2.
By the introduction of protonated 1, 3-di(4-pyridyl)propane (1, 3-dppH22+) and protonated bis(imidazol-1- ylmethyl)benzene (1, 4-bixH22+) as a cationic template, three new cobalt naphthalene-diphosphate coordination poly- mers based on 1, 4-naphthalenediphosphonic acid (1, 4-ndpaH4), namely (1, 3-dppH2)2[Co4(1, 4-ndpa)(1, 4-ndpaH)2(1, 4-ndpaH2)]·6H2O (1), (1, 4-bixH2)0.5[Co(1, 4-ndpaH)] (2), and (1, 4-bixH2)0.5[Co2(1, 4-ndpaH)(1, 4-ndpaH2)(H2O)2] (3), have been hydrothermally synthesized. Complexes 1-3 were characterized by elemental analysis, infrared spectros- copy, single crystal X -ray diffraction, powder X -ray diffraction, and thermogravimetric analysis, respectively. In complexes 1 and 2, inorganic chains of corner-sharing {CoO4} and {PO3C} tetrahedron are cross-linked by naphtha- lene ligands into 3D open-framework structures. The protonated di-pyridinium/imidazolium moieties, 1, 3-dppH22+ for 2 and 1, 4-bixH22+ for 2, lie inside the skeletal voids of the crystal structure, respectively. Interestingly, complex 3 with similar chemical composition to 2 except for an additional 1, 4-ndpaH22- ligand and two coordinated water mole- cules shows a 2D undulating layer structure, where the chains of corner-sharing {CoO5} trigonal bipyramid, {CoO6} octahedron, and {PO3C} tetrahedron are cross - linked by naphthalene groups. Adjacent layers are packed in AB stacking into the supramolecular structure, in which 1, 4-bixH22+ ions fill and balance the charge of 3. Magnetic stud- ies reveal that dominant antiferromagnetic interactions between the magnetic centers are propagated in complexes 1 and 2.
2023, 39(2): 346-356
doi: 10.11862/CJIC.2023.003
Abstract:
Herein, Co/C-N, Fe/C-N, and Fe-Co/C-N nanocomposites were obtained by the self-template method, and high-temperature pyrolysis of the mixture composed of dicyandiamide, sucrose, and cobalt (ferric) phthalocyanine as nitrogen, carbon, and metal sources respectively. Then a small amount of platinum was deposited on the Co/C-N with better oxygen reduction reaction (ORR) electroactivity by thermal reduction to obtain carbon nanosheet -supported Co-Pt nanoparticles (Co-Pt/C-N). The catalysts were well characterized and tested for ORR. The Co/C-N catalyst displayed the onset potential (Eonset) and half-wave potential (E1/2) of ORR closed to the Pt/C in an alkaline solution, and it even presented the more positive onset potential and half-wave potential in a neutral solution. For Co-Pt/C-N, its ORR electroactivity in an acidic solution was greatly enhanced compared with the Co/C-N and was comparable to the Pt/C. The excellent ORR electroactivity of the samples is mainly attributed to the 3D structure formed by the carbon nanosheets, uniform distribution of the metal nanoparticles, and abundant pyridine N.
Herein, Co/C-N, Fe/C-N, and Fe-Co/C-N nanocomposites were obtained by the self-template method, and high-temperature pyrolysis of the mixture composed of dicyandiamide, sucrose, and cobalt (ferric) phthalocyanine as nitrogen, carbon, and metal sources respectively. Then a small amount of platinum was deposited on the Co/C-N with better oxygen reduction reaction (ORR) electroactivity by thermal reduction to obtain carbon nanosheet -supported Co-Pt nanoparticles (Co-Pt/C-N). The catalysts were well characterized and tested for ORR. The Co/C-N catalyst displayed the onset potential (Eonset) and half-wave potential (E1/2) of ORR closed to the Pt/C in an alkaline solution, and it even presented the more positive onset potential and half-wave potential in a neutral solution. For Co-Pt/C-N, its ORR electroactivity in an acidic solution was greatly enhanced compared with the Co/C-N and was comparable to the Pt/C. The excellent ORR electroactivity of the samples is mainly attributed to the 3D structure formed by the carbon nanosheets, uniform distribution of the metal nanoparticles, and abundant pyridine N.
2023, 39(2): 357-366
doi: 10.11862/CJIC.2022.288
Abstract:
Applying waste LiFePO4 powders as raw material, the FePO4·2H2O precursor was effectively recycled through chemical precipitation. Thereafter, the formation mechanisms of the impurities were discussed. The potential (φ)-pH diagram of the Fe-P-Li-H2O system was investigated and the result demonstrated that FePO4·2H2O could form at a temperature of 298-363 K under a pH value of 0-5.0 by precipitation. The experiment results indicated that the Fe3PO7 phase started to form through the reaction of Fe(OH)3 and FePO4·2H2O during the sintering process. When the molar ratio of Fe and P (nFe∶nP) was 1∶1, pH=1.5-2.2, some Fe3+ ions will form Fe(OH)3, and the yield coefficient increased with the pH and temperature. This is because the solubility product constant (Ksp) of Fe(OH)3 was much less than the one of FePO4·2H2O, suggesting that the precipitate rate of Fe(OH)3 was faster than FePO4·2H2O. Based on thermodynamic principles, aging may be an effective way to convert Fe(OH)3 into FePO4 ·2H2O according to the φ-pH diagram of the Fe-P-Li-H2O system. Unfortunately, the rate of Fe(OH)3 conversion was slowed, resulting in some Fe(OH)3 in precipitation. Therefore, low pH value and temperature are essential to avoid Fe(OH)3 generation during the co-precipitation process. Also, when nFe∶nP=1∶2, some H3PO4 could react with NaOH to form NaH2PO4, which would further react with FePO4·2H2O to produce NaFeP2O7 during the sintering process. At 333 K, the equimolar ratio of co-precipitation precursor FePO4·2H2O can be obtained by adjusting the pH value at 1.5, matching the molar ratio of 1∶1 of Fe to P. The purity of this as-prepared FePO4·2H2O was 99.97%. Besides, the synthesized LiFePO4 which used this FePO4·2H2O as a precursor exhibited a reversible capacity of 154.1 mAh·g-1 and excellent capacity retention of 96.79% after 100 cycles at 0.2C (1C=180 mA·g-1). FePO4·2H2O obtained from waste LiFePO4 powders can be used as precursor to synthesize LiFePO4 cathode material, which greatly improves the economic effi-ciency of recycling the spent LiFePO4 battery.
Applying waste LiFePO4 powders as raw material, the FePO4·2H2O precursor was effectively recycled through chemical precipitation. Thereafter, the formation mechanisms of the impurities were discussed. The potential (φ)-pH diagram of the Fe-P-Li-H2O system was investigated and the result demonstrated that FePO4·2H2O could form at a temperature of 298-363 K under a pH value of 0-5.0 by precipitation. The experiment results indicated that the Fe3PO7 phase started to form through the reaction of Fe(OH)3 and FePO4·2H2O during the sintering process. When the molar ratio of Fe and P (nFe∶nP) was 1∶1, pH=1.5-2.2, some Fe3+ ions will form Fe(OH)3, and the yield coefficient increased with the pH and temperature. This is because the solubility product constant (Ksp) of Fe(OH)3 was much less than the one of FePO4·2H2O, suggesting that the precipitate rate of Fe(OH)3 was faster than FePO4·2H2O. Based on thermodynamic principles, aging may be an effective way to convert Fe(OH)3 into FePO4 ·2H2O according to the φ-pH diagram of the Fe-P-Li-H2O system. Unfortunately, the rate of Fe(OH)3 conversion was slowed, resulting in some Fe(OH)3 in precipitation. Therefore, low pH value and temperature are essential to avoid Fe(OH)3 generation during the co-precipitation process. Also, when nFe∶nP=1∶2, some H3PO4 could react with NaOH to form NaH2PO4, which would further react with FePO4·2H2O to produce NaFeP2O7 during the sintering process. At 333 K, the equimolar ratio of co-precipitation precursor FePO4·2H2O can be obtained by adjusting the pH value at 1.5, matching the molar ratio of 1∶1 of Fe to P. The purity of this as-prepared FePO4·2H2O was 99.97%. Besides, the synthesized LiFePO4 which used this FePO4·2H2O as a precursor exhibited a reversible capacity of 154.1 mAh·g-1 and excellent capacity retention of 96.79% after 100 cycles at 0.2C (1C=180 mA·g-1). FePO4·2H2O obtained from waste LiFePO4 powders can be used as precursor to synthesize LiFePO4 cathode material, which greatly improves the economic effi-ciency of recycling the spent LiFePO4 battery.
A 2D cyano-bridged WⅤ-CoⅡ coordination network exhibiting reversible thermal-induced charge transfer
2023, 39(2): 367-374
doi: 10.11862/CJIC.2023.001
Abstract:
Magnetic bistable materials featuring switchable spin states are of substantial interest in terms of their promising application in memory devices and switches. Here, we report a new magnetic bistable compound based on WⅤ-CoⅡ charge transfer. A 2D cyano-bridged heterobimetallic network {[WⅤ (CN)8]2[CoⅡ (4-nvp)4]3}·4CH3OH (1) (4-nvp=4-(2-(naphthalene-1-yl)vinyl)pyridine) is synthesized by incorporating the 4-nvp into the cyano-bridged WⅤ-CoⅡ layer framework to provide intra-and intermolecular π-π interaction. Magnetic studies show that compound 1 exhibits a reversible electron-transfer-coupled spin transition (ETCST) with interconversion between the WⅤ—CN— CoHSⅡ (HS=high spin) and WⅣ —CN—CoLSⅢ (LS=low spin) linkages, accompanied by a thermal hysteresis with a width of about 27 K.
Magnetic bistable materials featuring switchable spin states are of substantial interest in terms of their promising application in memory devices and switches. Here, we report a new magnetic bistable compound based on WⅤ-CoⅡ charge transfer. A 2D cyano-bridged heterobimetallic network {[WⅤ (CN)8]2[CoⅡ (4-nvp)4]3}·4CH3OH (1) (4-nvp=4-(2-(naphthalene-1-yl)vinyl)pyridine) is synthesized by incorporating the 4-nvp into the cyano-bridged WⅤ-CoⅡ layer framework to provide intra-and intermolecular π-π interaction. Magnetic studies show that compound 1 exhibits a reversible electron-transfer-coupled spin transition (ETCST) with interconversion between the WⅤ—CN— CoHSⅡ (HS=high spin) and WⅣ —CN—CoLSⅢ (LS=low spin) linkages, accompanied by a thermal hysteresis with a width of about 27 K.
2023, 39(2): 202-210
doi: 10.11862/CJIC.2023.006
Abstract:
Oxygen vacancies and hetero atom filling play an important role in the catalytic performance of materials. To develop an efficient and stable water electrolysis catalyst, based on the oxygen vacancies and phosphorus doping, nanoflower structures with oxygen vacancy and phosphorus doping were synthesized on iron foam by in-situ immersion growth and two-step heat treatment as hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) electrocatalysts. CoFe2O4 has been reported as a promising electrocatalyst for OER and oxygen reduction reaction (ORR). However, CoFe2O4 exhibits poor conductivity and slow electrocatalytic reaction in HER. The formation of oxygen vacancy (Ov) in CoFe2O4 can effectively regulate the electronic structure of the catalyst surface and contribute to the formation of more defects and vacancies, thus improving the activity of OER. Then, we added phosphorus atoms to fill the vacancy, and the prepared P-Ov-CoFe2O4/IF showed excellent performance of HER and OER in the alkaline electrocatalytic test. At the current density of 10 mA·cm-2, the overpotentials of HER and OER were only 54 and 191 mV, and the Tafel slopes were 57 and 54 mV·dec-1, respectively. The prepared electrocatalyst also dem-onstrated excellent cycling stability.
Oxygen vacancies and hetero atom filling play an important role in the catalytic performance of materials. To develop an efficient and stable water electrolysis catalyst, based on the oxygen vacancies and phosphorus doping, nanoflower structures with oxygen vacancy and phosphorus doping were synthesized on iron foam by in-situ immersion growth and two-step heat treatment as hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) electrocatalysts. CoFe2O4 has been reported as a promising electrocatalyst for OER and oxygen reduction reaction (ORR). However, CoFe2O4 exhibits poor conductivity and slow electrocatalytic reaction in HER. The formation of oxygen vacancy (Ov) in CoFe2O4 can effectively regulate the electronic structure of the catalyst surface and contribute to the formation of more defects and vacancies, thus improving the activity of OER. Then, we added phosphorus atoms to fill the vacancy, and the prepared P-Ov-CoFe2O4/IF showed excellent performance of HER and OER in the alkaline electrocatalytic test. At the current density of 10 mA·cm-2, the overpotentials of HER and OER were only 54 and 191 mV, and the Tafel slopes were 57 and 54 mV·dec-1, respectively. The prepared electrocatalyst also dem-onstrated excellent cycling stability.
2023, 39(2): 211-220
doi: 10.11862/CJIC.2022.285
Abstract:
The electronic and magnetic properties of nitrogen - passivated ZnO nanoribbons with armchair edges (NA8-ZnONRs) under electric field and strains were studied by density functional theory (DFT) at LDA+U level. Through the detailed calculation of the structures, electronic structures, and magnetism of the system, the results show that the pure ZnO nanoribbons with armchair edges (A8-ZnONRs) are a non-magnetic P-type semiconductor. NA8-ZnONRs have ferromagnetic metal characteristics. Its magnetism mainly comes from the spin polarization of N2p orbit (2.56μB) and O2p orbit (0.69μB), and the total magnetic moment is 3.21μB. NA8-ZnONRs system has a strong response to X - axis electric field. By adjusting the amplitude of the X - axis electric field, the magnetic moments of the system can be effectively adjusted. Under the action of X-axis electric field, the system still has fer- romagnetic metallicity, and the magnetism mainly comes from the spin polarization of N2p orbit and O2p orbit. After applying X-axis strains, the system still has ferromagnetic metallicity. Compared with the intrinsic magnetic moment of NA8-ZnONRs nanoribbons, the total magnetic moments of the system increase significantly, indicating that the system has an obvious corresponding effect on the strains. With the adjustment of strain amplitude, the change of total magnetic moment is flat. The results show that the application of strains can effectively adjust the magnetic moments of the system. However, the corresponding magnetic moments of the system to the strains change is not obvious in a small strain range.
The electronic and magnetic properties of nitrogen - passivated ZnO nanoribbons with armchair edges (NA8-ZnONRs) under electric field and strains were studied by density functional theory (DFT) at LDA+U level. Through the detailed calculation of the structures, electronic structures, and magnetism of the system, the results show that the pure ZnO nanoribbons with armchair edges (A8-ZnONRs) are a non-magnetic P-type semiconductor. NA8-ZnONRs have ferromagnetic metal characteristics. Its magnetism mainly comes from the spin polarization of N2p orbit (2.56μB) and O2p orbit (0.69μB), and the total magnetic moment is 3.21μB. NA8-ZnONRs system has a strong response to X - axis electric field. By adjusting the amplitude of the X - axis electric field, the magnetic moments of the system can be effectively adjusted. Under the action of X-axis electric field, the system still has fer- romagnetic metallicity, and the magnetism mainly comes from the spin polarization of N2p orbit and O2p orbit. After applying X-axis strains, the system still has ferromagnetic metallicity. Compared with the intrinsic magnetic moment of NA8-ZnONRs nanoribbons, the total magnetic moments of the system increase significantly, indicating that the system has an obvious corresponding effect on the strains. With the adjustment of strain amplitude, the change of total magnetic moment is flat. The results show that the application of strains can effectively adjust the magnetic moments of the system. However, the corresponding magnetic moments of the system to the strains change is not obvious in a small strain range.
2023, 39(2): 221-233
doi: 10.11862/CJIC.2022.274
Abstract:
WO3 and W18O49 were prepared by a solvothermal method using WCl6 as a precursor and applied in dyesensitized solar cells (DSSCs) and water electrolysis for hydrogen evolution reaction (HER). The structures and morphologies of WO3 and W18 O49 were characterized by X-ray diffractometer (XRD), field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM), respectively. The results showed both WO3 and W18O49 were monoclinic phases, and the morphology appeared as a cluster of oriented nanorods. X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR) proved that W18O49 contained abundant oxygen vacancies. Based on the excellent electrochemical properties of oxygen vacancies, the counter electrode with W18O49 based DSSCs obtained a power conversion efficiency (PCE) of 7.41%, which was higher than WO3 (6.12%) and Pt (7.27%). The cathode with W18O49 exhibited a low overpotential of 130 mV at 10 mA·cm-2 and a Tafel slope of 88 mV·dec-1 in alkaline hydrogen evolution. In addition, the W18O49 catalyst showed great electrocatalytic stability in both iodine electrolyte and 1.0 mol·L-1 KOH solution.
WO3 and W18O49 were prepared by a solvothermal method using WCl6 as a precursor and applied in dyesensitized solar cells (DSSCs) and water electrolysis for hydrogen evolution reaction (HER). The structures and morphologies of WO3 and W18 O49 were characterized by X-ray diffractometer (XRD), field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM), respectively. The results showed both WO3 and W18O49 were monoclinic phases, and the morphology appeared as a cluster of oriented nanorods. X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR) proved that W18O49 contained abundant oxygen vacancies. Based on the excellent electrochemical properties of oxygen vacancies, the counter electrode with W18O49 based DSSCs obtained a power conversion efficiency (PCE) of 7.41%, which was higher than WO3 (6.12%) and Pt (7.27%). The cathode with W18O49 exhibited a low overpotential of 130 mV at 10 mA·cm-2 and a Tafel slope of 88 mV·dec-1 in alkaline hydrogen evolution. In addition, the W18O49 catalyst showed great electrocatalytic stability in both iodine electrolyte and 1.0 mol·L-1 KOH solution.
2023, 39(2): 234-244
doi: 10.11862/CJIC.2022.290
Abstract:
The binary composite (BiOBr/RGO) composed of tetragonal BiOBr nanosheet and reduced graphene oxide (RGO) was firstly prepared by hydrothermal synthesis method, and then photocatalyst BiOBr-OV/RGO with the rich oxygen vacancy (OV) was further obtained by vacuum heat treatment. The crystal structure, chemical composition, and photoelectric properties were characterized by various techniques. The as-prepared BiOBr-OV/RGO composite photocatalyst exhibited the best photocatalytic activity for photocatalytic CO2 reduction under the simulated solar light. The best evolution rate of the main reduction product CO reached 15.67 μmol·g-1·h-1, which was 4.5, 2.5, and 1.4 times that of pure BiOBr, BiOBr-OV, and BiOBr/RGO, respectively. Furthermore, the photocatalytic reaction mechanism for BiOBr-OV/RGO could be attributed to the enhanced visible light absorption and the efficient photogenerated charge carrier separation, thereby boosting the photocatalytic reaction activity.
The binary composite (BiOBr/RGO) composed of tetragonal BiOBr nanosheet and reduced graphene oxide (RGO) was firstly prepared by hydrothermal synthesis method, and then photocatalyst BiOBr-OV/RGO with the rich oxygen vacancy (OV) was further obtained by vacuum heat treatment. The crystal structure, chemical composition, and photoelectric properties were characterized by various techniques. The as-prepared BiOBr-OV/RGO composite photocatalyst exhibited the best photocatalytic activity for photocatalytic CO2 reduction under the simulated solar light. The best evolution rate of the main reduction product CO reached 15.67 μmol·g-1·h-1, which was 4.5, 2.5, and 1.4 times that of pure BiOBr, BiOBr-OV, and BiOBr/RGO, respectively. Furthermore, the photocatalytic reaction mechanism for BiOBr-OV/RGO could be attributed to the enhanced visible light absorption and the efficient photogenerated charge carrier separation, thereby boosting the photocatalytic reaction activity.
2023, 39(2): 245-254
doi: 10.11862/CJIC.2023.005
Abstract:
Novel platelike MFI zeolite crystals were used as seeds to fabricate dense and flat MFI zeolite membranes with b-axis orientation on porous sintered quartz wool discs through a gel-free steam-assisted crystallization (GLSAC) method. Firstly, the platelike MFI crystals were coated on the porous support by a filtration method. Then the seeded support was dipped in a tetrapropylammonium hydroxide (TPAOH) aqueous solution followed by a drying step. Subsequently, the dried discs were heated in an autoclave with a small amount of water at the bottom to grow into continuous membranes. Influences of the TPAOH concentration, water at the autoclave bottom, temperature, and time on the MFI zeolite membranes were investigated. The results of the scanning electron microscope and X-ray diffraction show that the out-plane growth of the platelike MFI seeds was suppressed at an optimized TPAOH concentration and water content. A dense and flat MFI zeolite membrane with a thickness of about 750 nm was successfully prepared. Binary butane isomers separation tests revealed that a separation factor (SFA/B) of 36 at a permeation rate of 1.5×10-7 mol·m-2·s-1·Pa-1 for n-butane was achieved.
Novel platelike MFI zeolite crystals were used as seeds to fabricate dense and flat MFI zeolite membranes with b-axis orientation on porous sintered quartz wool discs through a gel-free steam-assisted crystallization (GLSAC) method. Firstly, the platelike MFI crystals were coated on the porous support by a filtration method. Then the seeded support was dipped in a tetrapropylammonium hydroxide (TPAOH) aqueous solution followed by a drying step. Subsequently, the dried discs were heated in an autoclave with a small amount of water at the bottom to grow into continuous membranes. Influences of the TPAOH concentration, water at the autoclave bottom, temperature, and time on the MFI zeolite membranes were investigated. The results of the scanning electron microscope and X-ray diffraction show that the out-plane growth of the platelike MFI seeds was suppressed at an optimized TPAOH concentration and water content. A dense and flat MFI zeolite membrane with a thickness of about 750 nm was successfully prepared. Binary butane isomers separation tests revealed that a separation factor (SFA/B) of 36 at a permeation rate of 1.5×10-7 mol·m-2·s-1·Pa-1 for n-butane was achieved.
2023, 39(2): 255-262
doi: 10.11862/CJIC.2022.283
Abstract:
To study the effect of substituents on iridium phosphorescent complexes, fluorine, methoxy, or trifluoromethyl were introduced into positions 2 and 4 of phenyl at the same time to obtain 2, 4-disubstituted phenyl-4-methylquinoline (2, 4-2R-mpq). Three new iridium phosphorescent complexes (2, 4-2R-mpq)2Ir(tmd) (R=F (1), MeO (2), CF3 (3)) were synthesized by using 2, 2, 6, 6-tetramethylheptanedione (tmd) as the auxiliary ligand, and 2, 4-2R-mpq with the electron-withdrawing group as the main ligands. The compositions and chemical structures of the complexes were characterized by elemental analysis, NMR spectroscopy, and single-crystal X-ray diffraction. The three iridium complexes belong to the triclinic system with the P1 space group. The photophysical properties of the complexes were studied by UV - Vis absorption spectroscopy, photoluminescence spectroscopy, and theory calculation. The results indicate that complexes 1, 2, and 3 with the photoluminescence quantum yields of 96%, 80%, and 80% exhibited maximum emission peaks at 570, 582, and 604 nm, respectively. When F and MeO are introduced into the 2 and 4 positions of phenyl on the main ligand, the electron cloud of complexes 1 and 2 are aggregated, while the CF3 is introduced, and the electron cloud of the complex is dispersed. Compared with complex 3, the emission wavelengths of complexes 1 and 2 had a significant blue shift. Different from traditional cognition, the methoxyl group represents an electron-withdrawing group.
To study the effect of substituents on iridium phosphorescent complexes, fluorine, methoxy, or trifluoromethyl were introduced into positions 2 and 4 of phenyl at the same time to obtain 2, 4-disubstituted phenyl-4-methylquinoline (2, 4-2R-mpq). Three new iridium phosphorescent complexes (2, 4-2R-mpq)2Ir(tmd) (R=F (1), MeO (2), CF3 (3)) were synthesized by using 2, 2, 6, 6-tetramethylheptanedione (tmd) as the auxiliary ligand, and 2, 4-2R-mpq with the electron-withdrawing group as the main ligands. The compositions and chemical structures of the complexes were characterized by elemental analysis, NMR spectroscopy, and single-crystal X-ray diffraction. The three iridium complexes belong to the triclinic system with the P1 space group. The photophysical properties of the complexes were studied by UV - Vis absorption spectroscopy, photoluminescence spectroscopy, and theory calculation. The results indicate that complexes 1, 2, and 3 with the photoluminescence quantum yields of 96%, 80%, and 80% exhibited maximum emission peaks at 570, 582, and 604 nm, respectively. When F and MeO are introduced into the 2 and 4 positions of phenyl on the main ligand, the electron cloud of complexes 1 and 2 are aggregated, while the CF3 is introduced, and the electron cloud of the complex is dispersed. Compared with complex 3, the emission wavelengths of complexes 1 and 2 had a significant blue shift. Different from traditional cognition, the methoxyl group represents an electron-withdrawing group.
2023, 39(2): 263-271
doi: 10.11862/CJIC.2022.279
Abstract:
The BiOIO3/BiOCl heterojunctions with different dominated facet, BiOIO3/{110}BiOCl and BiOIO3/{001} BiOCl, were prepared through facile solvothermal/hydrothermal methods with ethylene glycol/deionized water as solvents. As - prepared BiOIO3/BiOCl photocatalysts were characterized by X - ray diffraction, scanning electron microscope, energy-dispersive spectroscopy, and UV-Vis diffuse reflectance spectra. The photocatalytic activity of BiOIO3/BiOCl heterojunctions was evaluated by photo - catalytically decomposing rhodamine B and phenol in an aqueous solution under visible light irradiation. The results showed that 25% BiOIO3/{110}BiOCl heterojunctions exhibited the highest photocatalytic efficiency. The degradation of RhB over 25% BiOIO3/{110}BiOCl was 98.7% after 15 min of light irradiation. And 100% phenol can be degraded after irradiation for 150 min. The better photocatalytic performance of BiOIO3/{110}BiOCl may be attributed to the strong absorption of the visible light, the het- erojunction structure, and the efficient separation of photo-generated carriers benefiting from the dominated (110) facet of BiOCl. The superoxide radicals (·O2-) and holes (h+) are the main active species in the photocatalytic process. Moreover, a reasonable mechanism for enhanced photocatalytic performance was also discussed based on theexperimental results.
The BiOIO3/BiOCl heterojunctions with different dominated facet, BiOIO3/{110}BiOCl and BiOIO3/{001} BiOCl, were prepared through facile solvothermal/hydrothermal methods with ethylene glycol/deionized water as solvents. As - prepared BiOIO3/BiOCl photocatalysts were characterized by X - ray diffraction, scanning electron microscope, energy-dispersive spectroscopy, and UV-Vis diffuse reflectance spectra. The photocatalytic activity of BiOIO3/BiOCl heterojunctions was evaluated by photo - catalytically decomposing rhodamine B and phenol in an aqueous solution under visible light irradiation. The results showed that 25% BiOIO3/{110}BiOCl heterojunctions exhibited the highest photocatalytic efficiency. The degradation of RhB over 25% BiOIO3/{110}BiOCl was 98.7% after 15 min of light irradiation. And 100% phenol can be degraded after irradiation for 150 min. The better photocatalytic performance of BiOIO3/{110}BiOCl may be attributed to the strong absorption of the visible light, the het- erojunction structure, and the efficient separation of photo-generated carriers benefiting from the dominated (110) facet of BiOCl. The superoxide radicals (·O2-) and holes (h+) are the main active species in the photocatalytic process. Moreover, a reasonable mechanism for enhanced photocatalytic performance was also discussed based on theexperimental results.
2023, 39(2): 272-280
doi: 10.11862/CJIC.2023.004
Abstract:
Two-dimensional (2D) Janus WSSe, as an emerging transition metal dichalcogenides (TMDs) material, breaks the out-of-plane mirror symmetry and possesses abundant physical properties such as intrinsic vertical piezo-electricity and strong Rashba spin-orbit coupling effect, which has great application potential in spintronic devices. In this paper, the electronic structures, magnetic and optical properties of the Janus WSSe monolayer doped with transition metal atoms X (X=Mn, Fe, Co) were calculated using the first-principles plane wave method based on density functional theory. The results show that doping under Chalcogen-rich (chalcogen element is the majority element) condition exhibits higher stability than under W-rich (tungsten element is the majority element) condition, and all systems exhibit magnetic properties after doping. After Mn doping, the impurity levels appear in the spin-up channel, which changes the WSSe system from a non-magnetic semiconductor to a ferromagnetic semi-metal with a magnetic moment of 1.043μB. After Fe and Co doping, the impurity levels appear in both the spin-up and spin-down channels, making the Fe and Co-doped systems exhibit a metallic nature with magnetic moments of 1.584μB and 2.739μB, respectively. In addition, the static dielectric constant of the doped system is significantly increased, the polarization degree is enhanced, and both the imaginary part of the dielectric function and the optical absorption peak are red-shifted, indicating that doping is beneficial to the absorption of visible light.
Two-dimensional (2D) Janus WSSe, as an emerging transition metal dichalcogenides (TMDs) material, breaks the out-of-plane mirror symmetry and possesses abundant physical properties such as intrinsic vertical piezo-electricity and strong Rashba spin-orbit coupling effect, which has great application potential in spintronic devices. In this paper, the electronic structures, magnetic and optical properties of the Janus WSSe monolayer doped with transition metal atoms X (X=Mn, Fe, Co) were calculated using the first-principles plane wave method based on density functional theory. The results show that doping under Chalcogen-rich (chalcogen element is the majority element) condition exhibits higher stability than under W-rich (tungsten element is the majority element) condition, and all systems exhibit magnetic properties after doping. After Mn doping, the impurity levels appear in the spin-up channel, which changes the WSSe system from a non-magnetic semiconductor to a ferromagnetic semi-metal with a magnetic moment of 1.043μB. After Fe and Co doping, the impurity levels appear in both the spin-up and spin-down channels, making the Fe and Co-doped systems exhibit a metallic nature with magnetic moments of 1.584μB and 2.739μB, respectively. In addition, the static dielectric constant of the doped system is significantly increased, the polarization degree is enhanced, and both the imaginary part of the dielectric function and the optical absorption peak are red-shifted, indicating that doping is beneficial to the absorption of visible light.
2023, 39(2): 281-290
doi: 10.11862/CJIC.2022.262
Abstract:
We synthesized an oxygen-boron co-decorated multi-walled carbon nanotube material by a simple method. After that, it was used as a carrier to prepare platinum-based catalysts and carried out a variety of characterizations. The results indicated that the platinum particles supported on this carrier showed smaller particle size, higher electrochemical surface area (40 m2·gPt-1), and higher oxygen reduction activity (0.3 A·mgPt-1). Predictably, boron and oxygen play an important role in improving the dispersion of carbon nanotubes, controlling the uniformity and size of platinum particles, and promoting oxygen adsorption/dissociation in the oxygen reduction reaction.
We synthesized an oxygen-boron co-decorated multi-walled carbon nanotube material by a simple method. After that, it was used as a carrier to prepare platinum-based catalysts and carried out a variety of characterizations. The results indicated that the platinum particles supported on this carrier showed smaller particle size, higher electrochemical surface area (40 m2·gPt-1), and higher oxygen reduction activity (0.3 A·mgPt-1). Predictably, boron and oxygen play an important role in improving the dispersion of carbon nanotubes, controlling the uniformity and size of platinum particles, and promoting oxygen adsorption/dissociation in the oxygen reduction reaction.
2023, 39(2): 291-299
doi: 10.11862/CJIC.2022.266
Abstract:
Lightweight, 3D porous, and lithiophilic Al foams has been used as the hosts for Li metal anodes, and compounded with metallic Li by a facile mechanical extrusion method to obtain the Al@Li composite anodes. The high lithiophilicity of Al foams could provide abundant and uniform active sites for Li nucleation, thus inducing the fast nucleation and uniform electro-deposition of Li metal into the Al foams. Moreover, the 3D porous structures of Al foams could accommodate the huge volume change of Li metal anodes during the charge/discharge process and reduce the local current density, thus effectively inhibiting the growth of Li dendrites. Therefore, compared with the bare Li metal anodes, the obtained Al@Li composite anodes exhibited higher cycling stability of Li plating/stripping with a lower overpotential of ca. 5 mV at 1 mA·cm-2 after 250 cycles in their symmetric cells. Furthermore, half-cell configurations with the Al@Li composite anodes and LiFePO4 cathodes also presented significantly enhanced cycling capacity and rate performance.
Lightweight, 3D porous, and lithiophilic Al foams has been used as the hosts for Li metal anodes, and compounded with metallic Li by a facile mechanical extrusion method to obtain the Al@Li composite anodes. The high lithiophilicity of Al foams could provide abundant and uniform active sites for Li nucleation, thus inducing the fast nucleation and uniform electro-deposition of Li metal into the Al foams. Moreover, the 3D porous structures of Al foams could accommodate the huge volume change of Li metal anodes during the charge/discharge process and reduce the local current density, thus effectively inhibiting the growth of Li dendrites. Therefore, compared with the bare Li metal anodes, the obtained Al@Li composite anodes exhibited higher cycling stability of Li plating/stripping with a lower overpotential of ca. 5 mV at 1 mA·cm-2 after 250 cycles in their symmetric cells. Furthermore, half-cell configurations with the Al@Li composite anodes and LiFePO4 cathodes also presented significantly enhanced cycling capacity and rate performance.
2023, 39(2): 300-308
doi: 10.11862/CJIC.2022.251
Abstract:
In this study, TiO2/Cu2O/Pt composite hollow microspheres were prepared by precipitation and liquid deposition methods based on anatase TiO2 sol. The morphology and structure of different samples were controlled by different methods, the phase and structure, microscopic morphology, and optical properties of different samples were compared and analyzed. The results show that the introduction of Pt and Cu2O in the composites produces a syner-gistic effect, which effectively suppresses the electron- hole complexation, reduces the forbidden band width, and sig-nificantly enhances the light absorption in the visible region. Compared with TiO2, Cu2O and TiO2/Cu2O photocata-lysts, the TiO2/Cu2O/Pt photocatalyst had a significantly enhanced ability to degrade organic pollutants, can degrade 93% of methyl orange (MO) solution by 120 min of light, the degradation rate was 71% after four cycles, with excel-lent photocatalytic stability.
In this study, TiO2/Cu2O/Pt composite hollow microspheres were prepared by precipitation and liquid deposition methods based on anatase TiO2 sol. The morphology and structure of different samples were controlled by different methods, the phase and structure, microscopic morphology, and optical properties of different samples were compared and analyzed. The results show that the introduction of Pt and Cu2O in the composites produces a syner-gistic effect, which effectively suppresses the electron- hole complexation, reduces the forbidden band width, and sig-nificantly enhances the light absorption in the visible region. Compared with TiO2, Cu2O and TiO2/Cu2O photocata-lysts, the TiO2/Cu2O/Pt photocatalyst had a significantly enhanced ability to degrade organic pollutants, can degrade 93% of methyl orange (MO) solution by 120 min of light, the degradation rate was 71% after four cycles, with excel-lent photocatalytic stability.
2023, 39(2): 309-316
doi: 10.11862/CJIC.2022.267
Abstract:
Herein, we employed (CH3COO)2Zn as template to prepare B, N co - doped porous carbons (BN - PC) by using phenanthroline as precursor and N source, K2B4O7 as B source. The effect of template mass on the structure and electric storage properties of BN-PC5 was investigated. When the mass of (CH3COO)2Zn was 5 g, the B and N heteroatom content of BN - PC 5 was 20.21% and 18.29%, respectively. As the electrode materials for supercapaci-tors, BN-PC5 exhibited a high specific capacitance of 255 F·g-1 at 0.05 A·g-1, an excellent rate performance of 188 A·g-1 at 20 A·g-1 and outstanding cycle stability with 97% of initial capacitance retention after 10 000 cycles in 6 mol·L-1 KOH aqueous electrolyte. The energy density of BN-PC5 capacitor reached 27 Wh·kg-1 at an average power density of 56 W·kg-1 in 3 mol·L-1 ZnSO4 aqueous electrolyte.
Herein, we employed (CH3COO)2Zn as template to prepare B, N co - doped porous carbons (BN - PC) by using phenanthroline as precursor and N source, K2B4O7 as B source. The effect of template mass on the structure and electric storage properties of BN-PC5 was investigated. When the mass of (CH3COO)2Zn was 5 g, the B and N heteroatom content of BN - PC 5 was 20.21% and 18.29%, respectively. As the electrode materials for supercapaci-tors, BN-PC5 exhibited a high specific capacitance of 255 F·g-1 at 0.05 A·g-1, an excellent rate performance of 188 A·g-1 at 20 A·g-1 and outstanding cycle stability with 97% of initial capacitance retention after 10 000 cycles in 6 mol·L-1 KOH aqueous electrolyte. The energy density of BN-PC5 capacitor reached 27 Wh·kg-1 at an average power density of 56 W·kg-1 in 3 mol·L-1 ZnSO4 aqueous electrolyte.
2023, 39(2): 317-326
doi: 10.11862/CJIC.2022.289
Abstract:
Herein, we modified the natural product oleanolic acid with alkyne to synthesize the ligand OA-alkyne, and tethered it with cyclic metal iridium precursor CycloIr-N3 to obtain the final complex CycloIr-OA via copper(Ⅰ)-catalyzed azide-alkyne cycloaddition (CuAAC) reaction. The ligand and the complex were characterized by 1H NMR and ESI-MS. The results show that the complex had good lipophilicity, which was helpful to enter the cells quickly. The antitumor activity of CycloIr-OA and the mechanism of inducing tumor cell death were further studied by MTT, confocal imaging, and flow cytometry. After oleanolic acid was linked, the anti - cancer activity of complex CycloIr-OA was greatly improved. CycloIr-OA is enriched in the mitochondria of tumor cells, leading to the production of reactive oxygen species, and at the same time, it blocks the cell cycle in the S phase, ultimately inducing tumor cell necrosis.
Herein, we modified the natural product oleanolic acid with alkyne to synthesize the ligand OA-alkyne, and tethered it with cyclic metal iridium precursor CycloIr-N3 to obtain the final complex CycloIr-OA via copper(Ⅰ)-catalyzed azide-alkyne cycloaddition (CuAAC) reaction. The ligand and the complex were characterized by 1H NMR and ESI-MS. The results show that the complex had good lipophilicity, which was helpful to enter the cells quickly. The antitumor activity of CycloIr-OA and the mechanism of inducing tumor cell death were further studied by MTT, confocal imaging, and flow cytometry. After oleanolic acid was linked, the anti - cancer activity of complex CycloIr-OA was greatly improved. CycloIr-OA is enriched in the mitochondria of tumor cells, leading to the production of reactive oxygen species, and at the same time, it blocks the cell cycle in the S phase, ultimately inducing tumor cell necrosis.
2023, 39(2): 327-336
doi: 10.11862/CJIC.2022.292
Abstract:
Herein, we proposed a facial method to passivate surface defects on perovskite film by an amino acid derivative, Fmoc-Ile-OH molecule, which contains multifunctional groups, including carboxyl, amino, and Fmoc protecting group (with benzene ring). These functional groups exhibit a synergistic effect in improving perovskite film quality and stability. Specifically, we find that this modification could decrease the content of PbI2 impurity and enlarge the particle size of perovskite film. Moreover, the optical and interface carrier transport properties were improved apparently. The better diode ideality factors, lower trap-filled limit voltages, and higher carrier recombination resistance for modified perovskite solar cells all demonstrated that Fmoc-Ile-OH could effectively passivate surface defects in perovskite films. Finally, we obtain a device with high conversion efficiency, 21.09%, which is much better than the control one, 18.00%.
Herein, we proposed a facial method to passivate surface defects on perovskite film by an amino acid derivative, Fmoc-Ile-OH molecule, which contains multifunctional groups, including carboxyl, amino, and Fmoc protecting group (with benzene ring). These functional groups exhibit a synergistic effect in improving perovskite film quality and stability. Specifically, we find that this modification could decrease the content of PbI2 impurity and enlarge the particle size of perovskite film. Moreover, the optical and interface carrier transport properties were improved apparently. The better diode ideality factors, lower trap-filled limit voltages, and higher carrier recombination resistance for modified perovskite solar cells all demonstrated that Fmoc-Ile-OH could effectively passivate surface defects in perovskite films. Finally, we obtain a device with high conversion efficiency, 21.09%, which is much better than the control one, 18.00%.
2023, 39(2): 337-345
doi: 10.11862/CJIC.2022.269
Abstract:
N-doped carbon nanotube (NCNTs) with highly loaded metal catalysts (Fe/Ce-NCNTs) were synthesized via high-temperature pyrolysis method with Fe-based catalysts introducing Ce metallic. Ce metal can better promote the growth of carbon nanotubes (CNTs), anchoring more iron atoms and increasing the number of Fe—NX active sites. A highly conductive 3D network structure facilitates oxygen diffusion, electron transfer, and transport of reac-tion products. The Fe/Ce-NCNTs catalysts exhibited good catalytic activity (the half wave potential was 0.86 V (vs RHE)) and stability in alkaline media. Moreover, the assembled Al-air batteries (AABs) with Fe/Ce-NCNT exhibited a high performance with a power density of 142 mW·cm-2 and discharge specific capacity of 865 mAh·g-1 at 50 mA· cm-2. Fe/Ce-NCNTs possessed high voltage under a high current density load.
N-doped carbon nanotube (NCNTs) with highly loaded metal catalysts (Fe/Ce-NCNTs) were synthesized via high-temperature pyrolysis method with Fe-based catalysts introducing Ce metallic. Ce metal can better promote the growth of carbon nanotubes (CNTs), anchoring more iron atoms and increasing the number of Fe—NX active sites. A highly conductive 3D network structure facilitates oxygen diffusion, electron transfer, and transport of reac-tion products. The Fe/Ce-NCNTs catalysts exhibited good catalytic activity (the half wave potential was 0.86 V (vs RHE)) and stability in alkaline media. Moreover, the assembled Al-air batteries (AABs) with Fe/Ce-NCNT exhibited a high performance with a power density of 142 mW·cm-2 and discharge specific capacity of 865 mAh·g-1 at 50 mA· cm-2. Fe/Ce-NCNTs possessed high voltage under a high current density load.
2023, 39(2): 375-384
doi: 10.11862/CJIC.2023.002
Abstract:
A 1D coordination polymer [Zn2(H2L)2(4, 4′-bpy)2(H2O)]n (1) (H4L=1, 1′∶4′, 1″∶4″, 1‴-quterphenyl-2, 4, 2‴, 4‴-tetracarboxylic acid, 4, 4′-bpy=4, 4′-bipyridine) was synthesized by hydrothermal method, and its structure was characterized by single-crystal X-ray diffraction analysis, elemental analysis, infrared spectroscopy, thermogravimetric analysis, etc. The crystallographic analysis shows that complex 1 belongs to the triclinic crystal system with the space group of P1. Complex 1 consists of two zinc ions with different coordination geometries, which lie in a distorted trigonal bipyramidal {ZnNO4} and octahedral {ZnNO5} geometrical configuration, respectively. The two H2L2-ligands in complex 1 are linked to each other by zinc ions, forming an infinite 1D zigzag planar structure. The fluorescence sensing experiments indicated that the fluorescence of complex 1 could be quenched by 2, 4, 6-trinitrophenol and fluazinam with high sensitivity and selectivity. Moreover, the anti-interference of detection was also quite excellent.
A 1D coordination polymer [Zn2(H2L)2(4, 4′-bpy)2(H2O)]n (1) (H4L=1, 1′∶4′, 1″∶4″, 1‴-quterphenyl-2, 4, 2‴, 4‴-tetracarboxylic acid, 4, 4′-bpy=4, 4′-bipyridine) was synthesized by hydrothermal method, and its structure was characterized by single-crystal X-ray diffraction analysis, elemental analysis, infrared spectroscopy, thermogravimetric analysis, etc. The crystallographic analysis shows that complex 1 belongs to the triclinic crystal system with the space group of P1. Complex 1 consists of two zinc ions with different coordination geometries, which lie in a distorted trigonal bipyramidal {ZnNO4} and octahedral {ZnNO5} geometrical configuration, respectively. The two H2L2-ligands in complex 1 are linked to each other by zinc ions, forming an infinite 1D zigzag planar structure. The fluorescence sensing experiments indicated that the fluorescence of complex 1 could be quenched by 2, 4, 6-trinitrophenol and fluazinam with high sensitivity and selectivity. Moreover, the anti-interference of detection was also quite excellent.
