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2022 Volume 38 Issue 3
2022, 38(3): 377-398
doi: 10.11862/CJIC.2022.027
Abstract:
Highly sensitive and selective gas sensors are of great significance for real-time monitoring of toxic and harmful gases in the air and early diagnosis of diseases. At present, there are still many problems to be solved urgently for traditional gas-sensing materials. For example, the selectivity is poor and the detection limit, as well as the service life, is insufficient. Metal-organic frameworks (MOFs), as a kind of porous coordination polymers, have been widely used in the field of gas sensors due to their ultra-high specific surface areas and large porosities. MOFs and their derived metal oxides with different nanostructures can improve the sensitivity and selectivity of gas sensors. This provides new ideas and directions for preparing new high-performance gas sensors. Combining the gas sensing mechanism of metal oxide semiconductors (MOS), this article reviews the research progress of MOFs with different nanostructures and their derived metal oxides in the field of resistive gas sensors and prospects their applications and development directions.
Highly sensitive and selective gas sensors are of great significance for real-time monitoring of toxic and harmful gases in the air and early diagnosis of diseases. At present, there are still many problems to be solved urgently for traditional gas-sensing materials. For example, the selectivity is poor and the detection limit, as well as the service life, is insufficient. Metal-organic frameworks (MOFs), as a kind of porous coordination polymers, have been widely used in the field of gas sensors due to their ultra-high specific surface areas and large porosities. MOFs and their derived metal oxides with different nanostructures can improve the sensitivity and selectivity of gas sensors. This provides new ideas and directions for preparing new high-performance gas sensors. Combining the gas sensing mechanism of metal oxide semiconductors (MOS), this article reviews the research progress of MOFs with different nanostructures and their derived metal oxides in the field of resistive gas sensors and prospects their applications and development directions.
2022, 38(3): 399-406
doi: 10.11862/CJIC.2022.052
Abstract:
Nine benzimidazole-iridium(Ⅲ) complexes Ir-1a-Ir-3c were designed and synthesized by using fluorinated diphenylbenzimidazole derivatives as the main ligands and acetylacetone (corresponding complexes: Ir-1a-Ir-3a), 2-pyridine carboxylic acid (corresponding complexes: Ir-1b-Ir-3b), and 2-(5-trifluoromethyl-2H-[1,2,4]triazol-3-yl)-pyridine (tftp, corresponding complexes: Ir-1c-Ir-3c) as the auxiliary ligands, respectively. The effects of the degree of fluorination and different auxiliary ligands on the photophysical properties of the corresponding iridium complexes were investigated. The maximum emission wavelengths of the nine complexes were located in a range of 487-502 nm, showing green to blue-green phosphorescent emission. The largest blue shift was observed for the complexes based on tftp as an auxiliary ligand, especially for Ir-1c compared to Ir-1a with a blue shift of 17 nm. The nine complexes showed excellent photoluminescence efficiencies of 52%-87%. Furthermore, all iridium(Ⅲ) complexes exhibited good thermal stability, and the thermal decomposition temperatures were 313-390 ℃ (5% weight loss). Four iridium complexes of Ir-1c, Ir-2c, Ir-3c, and Ir-2b were selected for spin-coated electroluminescent devices with a doping concentration of 9%. The results show that the change of the primary and secondary ligands has a large effect on the luminescent color and luminescent efficiency of the light-emitting diodes. The Ir-3c-doped spin-coated devices had the highest device efficiency with an external quantum efficiency of 10.2%, a current efficiency of up to 30.3 cd·A-1, and a maximum power efficiency of 14.7 lm·W-1.
Nine benzimidazole-iridium(Ⅲ) complexes Ir-1a-Ir-3c were designed and synthesized by using fluorinated diphenylbenzimidazole derivatives as the main ligands and acetylacetone (corresponding complexes: Ir-1a-Ir-3a), 2-pyridine carboxylic acid (corresponding complexes: Ir-1b-Ir-3b), and 2-(5-trifluoromethyl-2H-[1,2,4]triazol-3-yl)-pyridine (tftp, corresponding complexes: Ir-1c-Ir-3c) as the auxiliary ligands, respectively. The effects of the degree of fluorination and different auxiliary ligands on the photophysical properties of the corresponding iridium complexes were investigated. The maximum emission wavelengths of the nine complexes were located in a range of 487-502 nm, showing green to blue-green phosphorescent emission. The largest blue shift was observed for the complexes based on tftp as an auxiliary ligand, especially for Ir-1c compared to Ir-1a with a blue shift of 17 nm. The nine complexes showed excellent photoluminescence efficiencies of 52%-87%. Furthermore, all iridium(Ⅲ) complexes exhibited good thermal stability, and the thermal decomposition temperatures were 313-390 ℃ (5% weight loss). Four iridium complexes of Ir-1c, Ir-2c, Ir-3c, and Ir-2b were selected for spin-coated electroluminescent devices with a doping concentration of 9%. The results show that the change of the primary and secondary ligands has a large effect on the luminescent color and luminescent efficiency of the light-emitting diodes. The Ir-3c-doped spin-coated devices had the highest device efficiency with an external quantum efficiency of 10.2%, a current efficiency of up to 30.3 cd·A-1, and a maximum power efficiency of 14.7 lm·W-1.
2022, 38(3): 407-414
doi: 10.11862/CJIC.2022.062
Abstract:
Using Ce(NO3)3·6H2O, orange peel as raw materials, aqueous ammonia as precipitant, CeO2·xH2O@OPP was synthesized via co-deposition method, and then CeO2@C composites were obtained by the calcination of CeO2·xH2O@OPP in N2. The resulted materials were characterized by FT-IR, X-ray diffraction, scanning electron microscope, Raman spectroscopy, UV-Vis, X-ray photoelectron spectroscopy, and photocurrent techniques. The results showed that Ce, C, O elements were evenly distributed in CeO2@C with many organic functional groups, abundant oxygen holes, and carbon bonds and that the organic functional groups in CeO2·xH2O@OPP, CeO2·xH2O, and CeO2@C were almost similar. The photocatalytic results illustrate that the introduction of C in CeO2@C is beneficial for the separation of photoelectrons and holes, and thus the improvement of photocurrent and photocatalytic efficiency and that the content of C in the resulted sample can greatly affect the adsorption and photocatalytic efficiency of organic dyes.
Using Ce(NO3)3·6H2O, orange peel as raw materials, aqueous ammonia as precipitant, CeO2·xH2O@OPP was synthesized via co-deposition method, and then CeO2@C composites were obtained by the calcination of CeO2·xH2O@OPP in N2. The resulted materials were characterized by FT-IR, X-ray diffraction, scanning electron microscope, Raman spectroscopy, UV-Vis, X-ray photoelectron spectroscopy, and photocurrent techniques. The results showed that Ce, C, O elements were evenly distributed in CeO2@C with many organic functional groups, abundant oxygen holes, and carbon bonds and that the organic functional groups in CeO2·xH2O@OPP, CeO2·xH2O, and CeO2@C were almost similar. The photocatalytic results illustrate that the introduction of C in CeO2@C is beneficial for the separation of photoelectrons and holes, and thus the improvement of photocurrent and photocatalytic efficiency and that the content of C in the resulted sample can greatly affect the adsorption and photocatalytic efficiency of organic dyes.
2022, 38(3): 415-422
doi: 10.11862/CJIC.2022.050
Abstract:
Oxygen evolution reaction (OER) catalysts play an important role in zinc-air batteries (ZABs). A novel non-noble metal-based self-supported carbon nanofiber (NiδFe4-δ-CNF) catalyst was developed. First, the network precursors were prepared from polyvinylpyrrolidone, transition metal acetate, and N, N-dimethylformamide via the electrostatic spinning method. After annealing at high temperature, the precursors were transformed into three-dimensional (3D) multi-pore structure material. The synthesized Ni1Fe1-CNF catalyst has a lower initial potential (230 mV) and overpotential (280 mV, 10 mA·cm-2) in electrolyte solution of 1 mol·L-1 KOH, and its performance is superior to that of commercial RuO2. Meanwhile, ZAB was assembled by mixing Ni1Fe1-CNF catalyst with commercial Pt/C catalyst as the air cathode. Compared with commercial RuO2+Pt/C ZAB, Ni1Fe1-CNF+Pt/C ZAB had a higher power density (122 mW·cm-2), lower charging voltage and better charge/discharge cycle stability.
Oxygen evolution reaction (OER) catalysts play an important role in zinc-air batteries (ZABs). A novel non-noble metal-based self-supported carbon nanofiber (NiδFe4-δ-CNF) catalyst was developed. First, the network precursors were prepared from polyvinylpyrrolidone, transition metal acetate, and N, N-dimethylformamide via the electrostatic spinning method. After annealing at high temperature, the precursors were transformed into three-dimensional (3D) multi-pore structure material. The synthesized Ni1Fe1-CNF catalyst has a lower initial potential (230 mV) and overpotential (280 mV, 10 mA·cm-2) in electrolyte solution of 1 mol·L-1 KOH, and its performance is superior to that of commercial RuO2. Meanwhile, ZAB was assembled by mixing Ni1Fe1-CNF catalyst with commercial Pt/C catalyst as the air cathode. Compared with commercial RuO2+Pt/C ZAB, Ni1Fe1-CNF+Pt/C ZAB had a higher power density (122 mW·cm-2), lower charging voltage and better charge/discharge cycle stability.
2022, 38(3): 423-429
doi: 10.11862/CJIC.2022.061
Abstract:
A small rhombohedral supramolecular building block (SBB) with a narrowed window was linked with amide-functionalized helical ligand 5, 5'-(((1, 1'-biphenyl)-2, 2'-dicarbonyl)bis(azanediyl))diisophthalic acid (H4L) for the first time, and a microporous metal-organic framework (MOF) [Cu2(L)(H2O)2]·DMF·6H2O (NTUniv-53) with pcu topology was formed. The synthesized NTUniv-53 showed a noticeable CO2 selective adsorption at room tempera-ture, which was insensitive to temperature change due to the narrowed windows and amide groups.
A small rhombohedral supramolecular building block (SBB) with a narrowed window was linked with amide-functionalized helical ligand 5, 5'-(((1, 1'-biphenyl)-2, 2'-dicarbonyl)bis(azanediyl))diisophthalic acid (H4L) for the first time, and a microporous metal-organic framework (MOF) [Cu2(L)(H2O)2]·DMF·6H2O (NTUniv-53) with pcu topology was formed. The synthesized NTUniv-53 showed a noticeable CO2 selective adsorption at room tempera-ture, which was insensitive to temperature change due to the narrowed windows and amide groups.
2022, 38(3): 430-440
doi: 10.11862/CJIC.2022.044
Abstract:
Temozolomide is the first-line anticancer drug for the clinical treatment of glioblastoma. In this work, temozolomide was chemically modified and introduced into the platinum(Ⅳ) complex. Two new Pt(Ⅳ) complexes P1T and P2T were successfully synthesized and characterized by 1H NMR and 13C NMR. The results show that both complexes had good lipid solubility with a fast hydrolysis rate. The anticancer activity and the mechanism of P1T and P2T were investigated with the MTT assay, flow cytometry, confocal imaging, and western blot. The results demonstrate that complexes P1T and P2T owned high cytotoxicity to glioma cell line A261, but low toxicity to normal nerve cell HT-22, indicating good cancer cell selectivity. Flow cytometry reveals that complexes P1T and P2T arrest the cell cycle in the G2/M phase, leading to DNA damage and ultimately inducing tumor cell apoptosis.
Temozolomide is the first-line anticancer drug for the clinical treatment of glioblastoma. In this work, temozolomide was chemically modified and introduced into the platinum(Ⅳ) complex. Two new Pt(Ⅳ) complexes P1T and P2T were successfully synthesized and characterized by 1H NMR and 13C NMR. The results show that both complexes had good lipid solubility with a fast hydrolysis rate. The anticancer activity and the mechanism of P1T and P2T were investigated with the MTT assay, flow cytometry, confocal imaging, and western blot. The results demonstrate that complexes P1T and P2T owned high cytotoxicity to glioma cell line A261, but low toxicity to normal nerve cell HT-22, indicating good cancer cell selectivity. Flow cytometry reveals that complexes P1T and P2T arrest the cell cycle in the G2/M phase, leading to DNA damage and ultimately inducing tumor cell apoptosis.
2022, 38(3): 441-448
doi: 10.11862/CJIC.2022.059
Abstract:
Using expandable graphite as raw material, graphite flakes were obtained through high-temperature expansion and mechanical sanding. Graphite flakes were used as templates to synthesize silicon carbide nanosheets (SiCNSs) with different specific surface areas. The effect of specific surface area on the photocatalytic hydrogen production performance of SiCNSs was explored. The results show that the specific surface area of SiCNSs has a significant impact on its hydrogen production performance, and increasing the specific surface area of the photocatalyst is beneficial to enhance its hydrogen production activity. The maximum specific surface area of SiCNSs can reach 149 m2·g-1, and its photolysis water hydrogen evolution rate was 51.0 μL·g-1·h-1. Based on the analysis of the structure and morphology of graphite flakes and SiCNSs, the formation mechanism of in situ generation of SiCNSs using graphite flakes as a template is proposed. The process mainly follows the gas-solid reaction mechanism. At high temperatures, gaseous SiO and Si react with graphite flakes to form SiCNSs, and the product better inherits the flake structure of graphite flakes. After removing carbon from the unreacted part of the large-size graphite sheet, a large number of nano-sized perforations were left, so that the specific surface area of the produced silicon carbide was higher than that of the small-size graphite sheet.
Using expandable graphite as raw material, graphite flakes were obtained through high-temperature expansion and mechanical sanding. Graphite flakes were used as templates to synthesize silicon carbide nanosheets (SiCNSs) with different specific surface areas. The effect of specific surface area on the photocatalytic hydrogen production performance of SiCNSs was explored. The results show that the specific surface area of SiCNSs has a significant impact on its hydrogen production performance, and increasing the specific surface area of the photocatalyst is beneficial to enhance its hydrogen production activity. The maximum specific surface area of SiCNSs can reach 149 m2·g-1, and its photolysis water hydrogen evolution rate was 51.0 μL·g-1·h-1. Based on the analysis of the structure and morphology of graphite flakes and SiCNSs, the formation mechanism of in situ generation of SiCNSs using graphite flakes as a template is proposed. The process mainly follows the gas-solid reaction mechanism. At high temperatures, gaseous SiO and Si react with graphite flakes to form SiCNSs, and the product better inherits the flake structure of graphite flakes. After removing carbon from the unreacted part of the large-size graphite sheet, a large number of nano-sized perforations were left, so that the specific surface area of the produced silicon carbide was higher than that of the small-size graphite sheet.
2022, 38(3): 449-458
doi: 10.11862/CJIC.2022.049
Abstract:
Size controllable near infrared-emitting ZGO∶1.5%Cr, xIn (Zn1.4Ga1.97-2xO4∶1.5%Cr, xIn, x=0%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%) persistent luminescent nanoparticles (PLNPs) were prepared via a facile one-step hydrothermal method. The size and persistent luminescence properties of ZGO∶1.5%Cr, xIn PLNPs depended on codoping amounts of In3+.The results showed that when the doping amount of In3+ was 0.2%, the average particle size of ZGO∶1.5%Cr, xIn PLNPs was the smallest (13.79 nm), and the NIR luminescence was the strongest. The afterglow time was estimated for 5 d, and can be re-excited by LED lamp. ZGO∶1.5%Cr, xIn PLNPs were pure spinel structure, and the doping of In3+ did not affect the crystal structure of PLNPs.
Size controllable near infrared-emitting ZGO∶1.5%Cr, xIn (Zn1.4Ga1.97-2xO4∶1.5%Cr, xIn, x=0%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%) persistent luminescent nanoparticles (PLNPs) were prepared via a facile one-step hydrothermal method. The size and persistent luminescence properties of ZGO∶1.5%Cr, xIn PLNPs depended on codoping amounts of In3+.The results showed that when the doping amount of In3+ was 0.2%, the average particle size of ZGO∶1.5%Cr, xIn PLNPs was the smallest (13.79 nm), and the NIR luminescence was the strongest. The afterglow time was estimated for 5 d, and can be re-excited by LED lamp. ZGO∶1.5%Cr, xIn PLNPs were pure spinel structure, and the doping of In3+ did not affect the crystal structure of PLNPs.
2022, 38(3): 459-468
doi: 10.11862/CJIC.2022.051
Abstract:
Tungsten carbide nanoflakes globular clusters (WC NFs) with the typical mesoporous structure were prepared by controlled breakdown anodization by a gas-solid carburization process. The crystal phase, microstructure, and pore size distribution of the nanoflowers were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), and N2 adsorption-desorption test. The electrochemical properties were evaluated using linear sweep voltammetry, cyclic voltammetry, chronoamperometry, and electro-chemical impedance spectroscopy in 1 mol·L-1 H2SO4 solution. The results showed that as-prepared WC NFs exhibited enhanced superior hydrogen evolution performance in terms of a small η10 (overpotential to obtain a current density of 10 mA·cm-2) of 150 mV, a Tafel slope of 56 mV·dec-1, and outstanding long-term cycling stability.
Tungsten carbide nanoflakes globular clusters (WC NFs) with the typical mesoporous structure were prepared by controlled breakdown anodization by a gas-solid carburization process. The crystal phase, microstructure, and pore size distribution of the nanoflowers were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), and N2 adsorption-desorption test. The electrochemical properties were evaluated using linear sweep voltammetry, cyclic voltammetry, chronoamperometry, and electro-chemical impedance spectroscopy in 1 mol·L-1 H2SO4 solution. The results showed that as-prepared WC NFs exhibited enhanced superior hydrogen evolution performance in terms of a small η10 (overpotential to obtain a current density of 10 mA·cm-2) of 150 mV, a Tafel slope of 56 mV·dec-1, and outstanding long-term cycling stability.
2022, 38(3): 469-478
doi: 10.11862/CJIC.2022.045
Abstract:
A Z-scheme α-Fe2O3/g-C3N4 photocatalyst was successfully prepared by the method of in-situ photodeposition-calcination. The as-prepared samples were characterized by transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, UV-Vis diffuse reflectance spectroscopy, photoluminescence spectroscopy, and electrochemical test. The photocatalytic activity was evaluated by visible-light-driven water-splitting hydrogen production. The results showed that when the loading amount of α-Fe2O3 was 2.9%, the photocatalyst exhibited remarkably high photocatalytic activity toward H2 evolution with a rate of 1 841.9 μmol·g-1·h-1, 3.3 times higher than that of pure g-C3N4. The enhanced performance is attributed to the following reasons: (1) α-Fe2O3 promotes exfoliation of g-C3N4 during high-temperature calcination, enlarging specific surface area and providing more active sites; (2) ultrafine α-Fe2O3 particles (5-8 nm) are highly uniformly dispersed on the surface of g-C3N4 and tightly combined to it, forming high-quality Z-scheme heterojunctions; (3) the Z-scheme structure not only effectively suppresses the photocarriers recombination, but also greatly retains the strong reduction originated from g-C3N4 conduction band and the strong oxidation originated from α-Fe2O3 valence band.
A Z-scheme α-Fe2O3/g-C3N4 photocatalyst was successfully prepared by the method of in-situ photodeposition-calcination. The as-prepared samples were characterized by transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, UV-Vis diffuse reflectance spectroscopy, photoluminescence spectroscopy, and electrochemical test. The photocatalytic activity was evaluated by visible-light-driven water-splitting hydrogen production. The results showed that when the loading amount of α-Fe2O3 was 2.9%, the photocatalyst exhibited remarkably high photocatalytic activity toward H2 evolution with a rate of 1 841.9 μmol·g-1·h-1, 3.3 times higher than that of pure g-C3N4. The enhanced performance is attributed to the following reasons: (1) α-Fe2O3 promotes exfoliation of g-C3N4 during high-temperature calcination, enlarging specific surface area and providing more active sites; (2) ultrafine α-Fe2O3 particles (5-8 nm) are highly uniformly dispersed on the surface of g-C3N4 and tightly combined to it, forming high-quality Z-scheme heterojunctions; (3) the Z-scheme structure not only effectively suppresses the photocarriers recombination, but also greatly retains the strong reduction originated from g-C3N4 conduction band and the strong oxidation originated from α-Fe2O3 valence band.
2022, 38(3): 479-488
doi: 10.11862/CJIC.2022.054
Abstract:
Porous carbon with a high specific surface area was prepared using a cheap coconut shell as raw material, and then the porous carbons were treated with nitric acid vapor in a closed reactor to improve the hydrophilicity of carbons. Using scanning transmission electron microscopy (TEM), physical adsorption, X-ray powder diffraction (XRD), Raman spectroscopy, and contact angle tests to measure the morphology, pore structure, composition, and hydrophilicity of carbons. The influence of nitric acid vapor on the morphology and structure of porous carbon materials at different temperatures was explored. Cyclic voltammetry, galvanostatic charge and discharge, and electro-chemical impedance methods were used to investigate the supercapacitor performance of porous carbon materials. The results showed that the specific surface areas and pore volumes of the porous carbon vapor were reduced after the post-treatment of nitric acid vapor, and the decrease was more obvious with the increase of the treatment temper-ature, while the hydrophilicity was getting better. Electrochemical test results showed that the porous carbon material (CSC-100) treated with 100 ℃ nitric acid vapor had the best supercapacitor performance. In the three electrodes system with 6 mol·L-1 KOH as the electrolyte, when the current density was 0.5 A·g-1, the specific capacitance of CSC-100 can reach 452.9 F·g-1, while the specific capacitance of untreated carbon (CSC) was only 350.4 F·g-1. The capacitance contribution analysis shows that the good hydrophilicity and surface functional groups of CSC-100 increase not only the electric double-layer capacitance but also improve the pseudocapacitance.
Porous carbon with a high specific surface area was prepared using a cheap coconut shell as raw material, and then the porous carbons were treated with nitric acid vapor in a closed reactor to improve the hydrophilicity of carbons. Using scanning transmission electron microscopy (TEM), physical adsorption, X-ray powder diffraction (XRD), Raman spectroscopy, and contact angle tests to measure the morphology, pore structure, composition, and hydrophilicity of carbons. The influence of nitric acid vapor on the morphology and structure of porous carbon materials at different temperatures was explored. Cyclic voltammetry, galvanostatic charge and discharge, and electro-chemical impedance methods were used to investigate the supercapacitor performance of porous carbon materials. The results showed that the specific surface areas and pore volumes of the porous carbon vapor were reduced after the post-treatment of nitric acid vapor, and the decrease was more obvious with the increase of the treatment temper-ature, while the hydrophilicity was getting better. Electrochemical test results showed that the porous carbon material (CSC-100) treated with 100 ℃ nitric acid vapor had the best supercapacitor performance. In the three electrodes system with 6 mol·L-1 KOH as the electrolyte, when the current density was 0.5 A·g-1, the specific capacitance of CSC-100 can reach 452.9 F·g-1, while the specific capacitance of untreated carbon (CSC) was only 350.4 F·g-1. The capacitance contribution analysis shows that the good hydrophilicity and surface functional groups of CSC-100 increase not only the electric double-layer capacitance but also improve the pseudocapacitance.
Chemical Co-precipitation Preparation of ZnMoO4/Aloe-Derived Porous Carbon and Catalytic Performance
2022, 38(3): 489-500
doi: 10.11862/CJIC.2022.046
Abstract:
Herein, aloe-derived porous carbon (APC), ZnMoO4, and ZnMoO4/APC catalysts were successfully prepared by two-step activation and chemical co-precipitation, respectively. As counter electrodes (CEs) in dyesensitized solar cells (DSSCs), the electrochemical properties and photovoltaic performance of these three CE catalysts in Cu-mediated DSSCs with D35 and Y123 dyes were explored. The microstructure, chemical composition, specific surface area, and porous textures of APC, ZnMoO4, and ZnMoO4/APC were characterized by field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), and N2 adsorption-desorption isotherms. The results show that APC was a porous network structure with a specific surface area of 1 439 m2·g-1, and ZnMoO4 nanoparticles were evenly embedded or dispersed on the surface of APC. ZnMoO4/APC delivered a power conversion efficiency (PCE) of 3.97% and 3.72% in the Cu2+/Cu+ electrolyte-based DSSCs with D35 and Y123 dyes, respectively, which was higher than that of APC (2.72%, 2.61%), ZnMoO4 (1.24%, 1.08%) and Pt (2.86%, 2.80%) at the same conditions.
Herein, aloe-derived porous carbon (APC), ZnMoO4, and ZnMoO4/APC catalysts were successfully prepared by two-step activation and chemical co-precipitation, respectively. As counter electrodes (CEs) in dyesensitized solar cells (DSSCs), the electrochemical properties and photovoltaic performance of these three CE catalysts in Cu-mediated DSSCs with D35 and Y123 dyes were explored. The microstructure, chemical composition, specific surface area, and porous textures of APC, ZnMoO4, and ZnMoO4/APC were characterized by field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), and N2 adsorption-desorption isotherms. The results show that APC was a porous network structure with a specific surface area of 1 439 m2·g-1, and ZnMoO4 nanoparticles were evenly embedded or dispersed on the surface of APC. ZnMoO4/APC delivered a power conversion efficiency (PCE) of 3.97% and 3.72% in the Cu2+/Cu+ electrolyte-based DSSCs with D35 and Y123 dyes, respectively, which was higher than that of APC (2.72%, 2.61%), ZnMoO4 (1.24%, 1.08%) and Pt (2.86%, 2.80%) at the same conditions.
2022, 38(3): 501-509
doi: 10.11862/CJIC.2022.047
Abstract:
Oxygen vacancies enact a vital role on the visible light absorption range and electron-hole separation efficiency of the photocatalytic material. Bismuth-based glass is rich in oxygen vacancy defects. BiOCl photocatalytic material was synthesized in-situ by hydrochloric acid corrosion of bismuth-based glass, and the influence of the outer body of the glass network on the oxygen vacancy concentration was studied. X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM) and electron paramagnetic resonance (EPR) were used to characterize the structure, morphology, and oxygen vacancy concentration of the synthesized BiOCl material. The results showed that the number of oxygen vacancies of the Bi2O3-B2O3-ZnO bismuth-based glass increased with the increase of the external body composition of the network. The in-situ synthesized BiOCl will "inherit"a large number of oxygen vacancies in the glass. The degradation rate of rhodamine B was as high as 93.1% under visible light for 100 min.
Oxygen vacancies enact a vital role on the visible light absorption range and electron-hole separation efficiency of the photocatalytic material. Bismuth-based glass is rich in oxygen vacancy defects. BiOCl photocatalytic material was synthesized in-situ by hydrochloric acid corrosion of bismuth-based glass, and the influence of the outer body of the glass network on the oxygen vacancy concentration was studied. X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM) and electron paramagnetic resonance (EPR) were used to characterize the structure, morphology, and oxygen vacancy concentration of the synthesized BiOCl material. The results showed that the number of oxygen vacancies of the Bi2O3-B2O3-ZnO bismuth-based glass increased with the increase of the external body composition of the network. The in-situ synthesized BiOCl will "inherit"a large number of oxygen vacancies in the glass. The degradation rate of rhodamine B was as high as 93.1% under visible light for 100 min.
2022, 38(3): 510-518
doi: 10.11862/CJIC.2022.057
Abstract:
TiO2 heterophase junctions are mainly prepared by high-temperature method, and it is difficult to control the morphology and composition of the prepared materials. Especially, it is still challenging to prepare a one-dimensional TiO2 heterophase junction at a lower temperature. In this paper, a simple and convenient one-step hydrothermal method was developed prepared one-dimensional nano-TiO2 heterophase junctions at a relatively low temperature (180 ℃). X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM) analyses show that the one-dimensional rutile TiO2 nanorods (length: (400±50) nm, diameter: (60±5) nm) are the basic structure of the prepared materials, and the anatase TiO2 nanoparticles with uniform size distribution (diameter: (9.5±0.5) nm) are loaded on the nanorods in a high-density, monodispersed form. By adjusting the hydrothermal time, the anatase TiO2 contents in the prepared materials could be controlled within the range of 20%-50%. The TiO2 heterophase junctions were successfully applied to the photocatalytic degradation of formaldehyde. When the content of anatase phase TiO2 was 33% (TiO2-24, the hydrothermal time was 24 h), the TiO2 heterophase junction had the best formaldehyde degradation performance. After 25 min photocatalytic reaction, the 92% of formaldehyde (120 mg·L-1) was degraded into CO2 under a low-intensity LED lamp (wavelength: 365 nm, light intensity: 12.26 mW·cm-2), confirming the efficient activity of the TiO2 heterophase junction. Steady-state fluorescence spectroscopy and photoelec-trochemical tests showed that charge separation and transfer efficiencies on TiO2-24 were much higher than those on other samples prepared at different hydrothermal times. The one-dimensional TiO2 heterophase junction not only is beneficial to the transfer of photogenerated charge but also can directionally drive the separation of the charges, which makes one-dimensional TiO2 heterophase photocatalyst has a higher formaldehyde degradation performance.
TiO2 heterophase junctions are mainly prepared by high-temperature method, and it is difficult to control the morphology and composition of the prepared materials. Especially, it is still challenging to prepare a one-dimensional TiO2 heterophase junction at a lower temperature. In this paper, a simple and convenient one-step hydrothermal method was developed prepared one-dimensional nano-TiO2 heterophase junctions at a relatively low temperature (180 ℃). X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM) analyses show that the one-dimensional rutile TiO2 nanorods (length: (400±50) nm, diameter: (60±5) nm) are the basic structure of the prepared materials, and the anatase TiO2 nanoparticles with uniform size distribution (diameter: (9.5±0.5) nm) are loaded on the nanorods in a high-density, monodispersed form. By adjusting the hydrothermal time, the anatase TiO2 contents in the prepared materials could be controlled within the range of 20%-50%. The TiO2 heterophase junctions were successfully applied to the photocatalytic degradation of formaldehyde. When the content of anatase phase TiO2 was 33% (TiO2-24, the hydrothermal time was 24 h), the TiO2 heterophase junction had the best formaldehyde degradation performance. After 25 min photocatalytic reaction, the 92% of formaldehyde (120 mg·L-1) was degraded into CO2 under a low-intensity LED lamp (wavelength: 365 nm, light intensity: 12.26 mW·cm-2), confirming the efficient activity of the TiO2 heterophase junction. Steady-state fluorescence spectroscopy and photoelec-trochemical tests showed that charge separation and transfer efficiencies on TiO2-24 were much higher than those on other samples prepared at different hydrothermal times. The one-dimensional TiO2 heterophase junction not only is beneficial to the transfer of photogenerated charge but also can directionally drive the separation of the charges, which makes one-dimensional TiO2 heterophase photocatalyst has a higher formaldehyde degradation performance.
2022, 38(3): 519-527
doi: 10.11862/CJIC.2022.060
Abstract:
A new two-dimensional metal-organic framework (Fe-MOF) was self-assembled by ferrous tetrafluoroborate hexahydrate, potassium tetracyanoplatinate trihydrate, and 4-picoline-N-oxide in water and ethanol. Singlecrystal X-ray crystallography reveals that Fe-MOF crystallized in the monoclinic space group P21/c. [Pt(CN)4]2- is bridged by four Fe atoms through the cyano group, while Fe atom is connected with four N atoms from [Pt(CN)4]2-, forming Fe-MOF with (4, 4)-grid structure. Fe-MOF is stacked by a two-dimensional layer in an AB mode along the caxis by virtue of van der Waals forces, and the layer distance is 0.6 nm. The Fe(Ⅱ) centers have two [FeN4O2] octahedral coordination environments: one of them is connected axially with two water molecules, while the other is connected axially with a water molecule and a 4-picoline-N-oxide. Metal-organic layer (Fe-MOL) was prepared by ultrasonically exfoliating Fe-MOF. Fe-MOL maintained the two-dimensional crystalline structure as evidenced by infrared spectroscopy (FT-IR) and X-ray powder diffraction (PXRD). Scanning electron microscope (SEM) and transmission electron microscope (TEM) characterizations showed that Fe-MOL had a nanolayered structure. Fe-MOL was proved to be an ultra-thin layered structure of about 5 nm by atomic force microscopy (AFM). Fe-MOL exhibited ultrafast catalytic speed and ultrahigh catalytic efficiency in the catalytic oxidation reaction of 2, 2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) due to the coordination environment of the Fe(Ⅱ) center possessing a similar natural heme structure. The color of the solution changed from colorless to dark green in just 16 s, and the apparent second-order rate constant (kcat/Km; kcat is catalytic constant, Km is Michaelis constant) was as high as 4.70×106 mmol-1·L·s-1. Fe-MOL exhibited good cycle stability and it still had 90% catalytic activity after five catalytic cycles. The excellent catalytic efficiency of Fe-MOL exceeded most of the reported MOF biomimetic catalysts.
A new two-dimensional metal-organic framework (Fe-MOF) was self-assembled by ferrous tetrafluoroborate hexahydrate, potassium tetracyanoplatinate trihydrate, and 4-picoline-N-oxide in water and ethanol. Singlecrystal X-ray crystallography reveals that Fe-MOF crystallized in the monoclinic space group P21/c. [Pt(CN)4]2- is bridged by four Fe atoms through the cyano group, while Fe atom is connected with four N atoms from [Pt(CN)4]2-, forming Fe-MOF with (4, 4)-grid structure. Fe-MOF is stacked by a two-dimensional layer in an AB mode along the caxis by virtue of van der Waals forces, and the layer distance is 0.6 nm. The Fe(Ⅱ) centers have two [FeN4O2] octahedral coordination environments: one of them is connected axially with two water molecules, while the other is connected axially with a water molecule and a 4-picoline-N-oxide. Metal-organic layer (Fe-MOL) was prepared by ultrasonically exfoliating Fe-MOF. Fe-MOL maintained the two-dimensional crystalline structure as evidenced by infrared spectroscopy (FT-IR) and X-ray powder diffraction (PXRD). Scanning electron microscope (SEM) and transmission electron microscope (TEM) characterizations showed that Fe-MOL had a nanolayered structure. Fe-MOL was proved to be an ultra-thin layered structure of about 5 nm by atomic force microscopy (AFM). Fe-MOL exhibited ultrafast catalytic speed and ultrahigh catalytic efficiency in the catalytic oxidation reaction of 2, 2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) due to the coordination environment of the Fe(Ⅱ) center possessing a similar natural heme structure. The color of the solution changed from colorless to dark green in just 16 s, and the apparent second-order rate constant (kcat/Km; kcat is catalytic constant, Km is Michaelis constant) was as high as 4.70×106 mmol-1·L·s-1. Fe-MOL exhibited good cycle stability and it still had 90% catalytic activity after five catalytic cycles. The excellent catalytic efficiency of Fe-MOL exceeded most of the reported MOF biomimetic catalysts.
2022, 38(3): 528-534
doi: 10.11862/CJIC.2022.048
Abstract:
To study the influencing factors and photoelectric properties of graphene adsorbed by TiCl4 molecules, and explore the possibility of the composite applied to sensors and transparent conductive films, first-principles calculations and Monte Carlo methods were carried out to study the adsorption performance and photoelectric properties of TiCl4 gas molecules on the surface of graphene. The results reveal that: (1) graphene has a strong physical adsorption effect on TiCl4 gas molecules. Cl atoms, sitting at the top of carbon atoms farthest from the center of mass is the most stable configuration. (2) The increase in temperature is not conducive to the adsorption of TiCl4 gas molecules, but the increase of gas fugacity is conducive. The temperature should be maintained near the boiling point of TiCl4 and the pressure of the gas be increased when TiCl4 gas molecules are inserted into graphite/double-layer graphene/multilayer graphene. (3) The adsorption of TiCl4 regulates the electronic structure of graphene, significantly improves the density of states near the Fermi level, reduces the pseudo-energy gap, and effectively improves the conductivity. (4) In the visible region, the adsorption of TiCl4 has little effect on the absorption performance of the system, and does not affect the optical properties of the transparent conductive film while improving the conductivity of the film.
To study the influencing factors and photoelectric properties of graphene adsorbed by TiCl4 molecules, and explore the possibility of the composite applied to sensors and transparent conductive films, first-principles calculations and Monte Carlo methods were carried out to study the adsorption performance and photoelectric properties of TiCl4 gas molecules on the surface of graphene. The results reveal that: (1) graphene has a strong physical adsorption effect on TiCl4 gas molecules. Cl atoms, sitting at the top of carbon atoms farthest from the center of mass is the most stable configuration. (2) The increase in temperature is not conducive to the adsorption of TiCl4 gas molecules, but the increase of gas fugacity is conducive. The temperature should be maintained near the boiling point of TiCl4 and the pressure of the gas be increased when TiCl4 gas molecules are inserted into graphite/double-layer graphene/multilayer graphene. (3) The adsorption of TiCl4 regulates the electronic structure of graphene, significantly improves the density of states near the Fermi level, reduces the pseudo-energy gap, and effectively improves the conductivity. (4) In the visible region, the adsorption of TiCl4 has little effect on the absorption performance of the system, and does not affect the optical properties of the transparent conductive film while improving the conductivity of the film.
2022, 38(3): 535-541
doi: 10.11862/CJIC.2022.042
Abstract:
A new Dy2 complex [Dy2(L)2(acac)2(CH3CH2OH)2] (1) has been synthesized based on a multidentate Schiff base H2L (H2L=N'-(2-hydroxynaphthalen-1-ylmethylene)-2-(hydroxyimino)propanehydrazide) and β-diketone coligand Hacac (Hacac=acetylacetone). Complex 1 was characterized by single-crystal X-ray diffraction, elemental analysis and further investigated by magnetic measurements. Structural analysis reveals that complex 1 is a centro-symmetric dinuclear dysprosium complex and the asymmetric unit contains a Dy(Ⅲ) ion, one L2- ligand, one acac- coligand, and an ethanol molecule. Each of the Dy(Ⅲ) centers is eight-coordinate and adopts a distorted bicapped trigonal-prismatic coordination geometry. Magnetic studies suggest the existence of weak antiferromagnetic interactions between the Dy(Ⅲ) ions in 1. In addition, the slow magnetic relaxation behaviors are observed in 1 with the magnetic energy barrier ΔE/kB=14.52 K and the pre-exponential factor τ0=7.58×10-6 s.
A new Dy2 complex [Dy2(L)2(acac)2(CH3CH2OH)2] (1) has been synthesized based on a multidentate Schiff base H2L (H2L=N'-(2-hydroxynaphthalen-1-ylmethylene)-2-(hydroxyimino)propanehydrazide) and β-diketone coligand Hacac (Hacac=acetylacetone). Complex 1 was characterized by single-crystal X-ray diffraction, elemental analysis and further investigated by magnetic measurements. Structural analysis reveals that complex 1 is a centro-symmetric dinuclear dysprosium complex and the asymmetric unit contains a Dy(Ⅲ) ion, one L2- ligand, one acac- coligand, and an ethanol molecule. Each of the Dy(Ⅲ) centers is eight-coordinate and adopts a distorted bicapped trigonal-prismatic coordination geometry. Magnetic studies suggest the existence of weak antiferromagnetic interactions between the Dy(Ⅲ) ions in 1. In addition, the slow magnetic relaxation behaviors are observed in 1 with the magnetic energy barrier ΔE/kB=14.52 K and the pre-exponential factor τ0=7.58×10-6 s.
2022, 38(3): 542-550
doi: 10.11862/CJIC.2022.043
Abstract:
Bi12O17Br2 photocatalyst was prepared through a one-pot hydrothermal method. An average microsheets size of 1.2 μm and a high specific surface area of ca. 29 m2·g-1 were observed for Bi12O17Br2 photocatalyst. Bi12O17Br2 has a bandgap of 2.42 eV, which can be excited under visible light illumination. The photoinduced oxygen vacancies are easily generated on the surface of Bi12O17Br2. The N2 molecules could be captured and activated by oxygen vacancies. An NH3 generation rate of 337.6 μmol·g-1·h-1 was detected on Bi12O17Br2 under visible light irradiation. It demonstrates that the accomplishment of the visible-light-driven photocatalytic for the N2 photo fixation with H2O over a Bi12O17Br2 photocatalyst.
Bi12O17Br2 photocatalyst was prepared through a one-pot hydrothermal method. An average microsheets size of 1.2 μm and a high specific surface area of ca. 29 m2·g-1 were observed for Bi12O17Br2 photocatalyst. Bi12O17Br2 has a bandgap of 2.42 eV, which can be excited under visible light illumination. The photoinduced oxygen vacancies are easily generated on the surface of Bi12O17Br2. The N2 molecules could be captured and activated by oxygen vacancies. An NH3 generation rate of 337.6 μmol·g-1·h-1 was detected on Bi12O17Br2 under visible light irradiation. It demonstrates that the accomplishment of the visible-light-driven photocatalytic for the N2 photo fixation with H2O over a Bi12O17Br2 photocatalyst.
2022, 38(3): 551-558
doi: 10.11862/CJIC.2022.056
Abstract:
Two-dimensional coordination polymer of [Tb(1, 4-bdc)1.5(phen)(H2O)]n (1) (1, 4-H2bdc=terephthalic acid, phen=1, 10-phenanthroline) was synthesized by solvothermal approach. Complex 1 was characterized by single-crystal X-ray diffraction, powder X-ray diffraction, FT-IR spectroscopy, elemental analysis, and fluorescence spectra. X-ray diffraction crystallographic analyses show that complex 1 crystallizes in the triclinic crystal system P1 space group; two adjacent Tb(Ⅲ) ions are bridged by —O—C—O— from four 1, 4-bdc2- into a binuclear unit, and further bridged by 1, 4-bdc2- into an infinite 2D layered structure. The fluorescence experiment proved that the complex 1 can detect Fe3+ through the fluorescence quenching mechanism with Ksv=8.39×103 L·mol-1 and limit of detection of 0.017 μmol·L-1.
Two-dimensional coordination polymer of [Tb(1, 4-bdc)1.5(phen)(H2O)]n (1) (1, 4-H2bdc=terephthalic acid, phen=1, 10-phenanthroline) was synthesized by solvothermal approach. Complex 1 was characterized by single-crystal X-ray diffraction, powder X-ray diffraction, FT-IR spectroscopy, elemental analysis, and fluorescence spectra. X-ray diffraction crystallographic analyses show that complex 1 crystallizes in the triclinic crystal system P1 space group; two adjacent Tb(Ⅲ) ions are bridged by —O—C—O— from four 1, 4-bdc2- into a binuclear unit, and further bridged by 1, 4-bdc2- into an infinite 2D layered structure. The fluorescence experiment proved that the complex 1 can detect Fe3+ through the fluorescence quenching mechanism with Ksv=8.39×103 L·mol-1 and limit of detection of 0.017 μmol·L-1.
2022, 38(3): 559-568
doi: 10.11862/CJIC.2022.053
Abstract:
Using 1, 4, 5, 8-naphthalene tetracarboxylic acid as a raw material, a luminescent barium-based metalorganic framework (MOF), [Ba(dna)(H2O)2]n (1, H2dna=1, 8-naphthalic anhydride-4, 5-dicarboxylic), with a 3D topological structure was synthesized by in situ reaction under solvothermal conditions, and characterized by single-crystal X-ray diffraction, elemental analysis, thermogravimetric analysis, and powder X-ray diffraction. The structural analysis demonstrates that it has the underlying 3D topology, encompassing a π-conjugated organic ligand with an anhydride group. It exhibited a low detection limit for aromatic amines in an aqueous solution, which may be driven by an anhydride amine reaction between the ligand and the hosted amines, with a significant enhancement of the emission intensity and visual color change. Furthermore, micro-crystalline BaCO3 particles can be prepared through direct calcination of complex 1 as a precursor at moderately elevated temperatures.
Using 1, 4, 5, 8-naphthalene tetracarboxylic acid as a raw material, a luminescent barium-based metalorganic framework (MOF), [Ba(dna)(H2O)2]n (1, H2dna=1, 8-naphthalic anhydride-4, 5-dicarboxylic), with a 3D topological structure was synthesized by in situ reaction under solvothermal conditions, and characterized by single-crystal X-ray diffraction, elemental analysis, thermogravimetric analysis, and powder X-ray diffraction. The structural analysis demonstrates that it has the underlying 3D topology, encompassing a π-conjugated organic ligand with an anhydride group. It exhibited a low detection limit for aromatic amines in an aqueous solution, which may be driven by an anhydride amine reaction between the ligand and the hosted amines, with a significant enhancement of the emission intensity and visual color change. Furthermore, micro-crystalline BaCO3 particles can be prepared through direct calcination of complex 1 as a precursor at moderately elevated temperatures.
