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2024 Volume 40 Issue 2
2024, 40(2): 289-306
doi: 10.11862/CJIC.20230121
Abstract:
Transition metal-based materials with relatively low cost and excellent catalytic performance are considered as the most promising candidates to replace noble metal-based electrocatalysts in the field of overall water splitting. However, their wide applications are hindered by the limited active sites and relatively poor electrical conductivity. The doping of non-metallic elements can modulate the electronic structure of the host material and optimize the adsorption energy, thus positively affecting the activity and stability of transition metal-based electrocatalysts and narrowing the performance gap between them and precious metal materials. In this paper, we summarize the recent research on the modification of non-metallic elements in transition metal-based electrocatalytic materials, systematically review the methods of non-metallic element doping (high-temperature calcination, hydrothermal/solvent thermal, plasma treatment and electrodeposition), the doping effects of different non-metallic elements (single non-metallic element doping, multi-nonmetallic element doping and composite doping), and analyze the effects of non-metallic element modification on transition metal-based electrocatalysts from multiple perspectives of physicochemical property changes and electronic structure changes. The effects of non-metallic element modification on transition metal-based materials are analyzed from the perspectives of physicochemical property change and electronic structure change. In the end, the future development direction of non-metallic element doped transition metalbased electrocatalysts is prospected.
Transition metal-based materials with relatively low cost and excellent catalytic performance are considered as the most promising candidates to replace noble metal-based electrocatalysts in the field of overall water splitting. However, their wide applications are hindered by the limited active sites and relatively poor electrical conductivity. The doping of non-metallic elements can modulate the electronic structure of the host material and optimize the adsorption energy, thus positively affecting the activity and stability of transition metal-based electrocatalysts and narrowing the performance gap between them and precious metal materials. In this paper, we summarize the recent research on the modification of non-metallic elements in transition metal-based electrocatalytic materials, systematically review the methods of non-metallic element doping (high-temperature calcination, hydrothermal/solvent thermal, plasma treatment and electrodeposition), the doping effects of different non-metallic elements (single non-metallic element doping, multi-nonmetallic element doping and composite doping), and analyze the effects of non-metallic element modification on transition metal-based electrocatalysts from multiple perspectives of physicochemical property changes and electronic structure changes. The effects of non-metallic element modification on transition metal-based materials are analyzed from the perspectives of physicochemical property change and electronic structure change. In the end, the future development direction of non-metallic element doped transition metalbased electrocatalysts is prospected.
2024, 40(2): 307-315
doi: 10.11862/CJIC.20230324
Abstract:
Two Dy4 clusters with the formulae [Dy4(L)4(PhCO2)2(NO3)2(EtOH)2] (1) and [Dy4(L)4(2-NO2-PhCO2)2(NO3)2(EtOH)2] (2) were obtained by the reactions of Dy(NO3)3·6H2O with a Schiff base ligand 2-(((2-hydroxy-3-methoxy-benzyl)imino)methyl)-4-methoxyphenol (H2L) and two auxiliary ligands PhCO2H and 2-NO2-PhCO2H in ethanol. Single crystal X-ray diffraction studies evidenced that the two complexes are constructed from Dy2 units, and display a centrosymmetric tetranuclear linear chain structure. One metal center in the Dy2 unit in 1 and 2 presents a sevencoordinated geometry, and the other Dy(Ⅲ) ion displays an eight-coordinated geometry. Both complexes are identified as single-molecule magnets with energy barriers of 110 and 108 K, respectively. Theoretical calculations also analyzed the magnetic properties of 1 and 2.
Two Dy4 clusters with the formulae [Dy4(L)4(PhCO2)2(NO3)2(EtOH)2] (1) and [Dy4(L)4(2-NO2-PhCO2)2(NO3)2(EtOH)2] (2) were obtained by the reactions of Dy(NO3)3·6H2O with a Schiff base ligand 2-(((2-hydroxy-3-methoxy-benzyl)imino)methyl)-4-methoxyphenol (H2L) and two auxiliary ligands PhCO2H and 2-NO2-PhCO2H in ethanol. Single crystal X-ray diffraction studies evidenced that the two complexes are constructed from Dy2 units, and display a centrosymmetric tetranuclear linear chain structure. One metal center in the Dy2 unit in 1 and 2 presents a sevencoordinated geometry, and the other Dy(Ⅲ) ion displays an eight-coordinated geometry. Both complexes are identified as single-molecule magnets with energy barriers of 110 and 108 K, respectively. Theoretical calculations also analyzed the magnetic properties of 1 and 2.
2024, 40(2): 316-324
doi: 10.11862/CJIC.20230327
Abstract:
A novel intermittent hydrothermal method was applied to synthesize mordenite zeolite membrane. The membrane was synthesized in a template-free synthetic solution using commercially available, economical, macroporous α-Al2O3 tube as the substrate. The out surface of the substrate was coated with a mordenite seed layer via a hotdip coating procedure. The influences of the traditional continuous heating method and the novel intermittent heating method on the morphology, microstructure and pervaporation performance for isopropanol dehydration of the mordenite membranes were compared. The impacts of molar ratios of Na2O/SiO2, SiO2/Al2O3, and NaF/SiO2 in the synthetic solution on the preparation of mordenite zeolite membranes under intermittent hydrothermal synthesis were investigated. The as-synthesized mordenite zeolite membrane showed maximum pervaporation performance for isopropanol dehydration under optimized synthetic solution composition with the molar ratios of Na2O/SiO2, SiO2/Al2O3, and NaF/SiO2 were 0.24, 16.7 and 0.25, respectively. The maximum water permeation flux was 5.60 kg·m-2·h-1 and the separation factor was greater than 10 000, respectively, in the dehydration of isopropanol/water mixture (9∶1, w/w) at 75 ℃.
A novel intermittent hydrothermal method was applied to synthesize mordenite zeolite membrane. The membrane was synthesized in a template-free synthetic solution using commercially available, economical, macroporous α-Al2O3 tube as the substrate. The out surface of the substrate was coated with a mordenite seed layer via a hotdip coating procedure. The influences of the traditional continuous heating method and the novel intermittent heating method on the morphology, microstructure and pervaporation performance for isopropanol dehydration of the mordenite membranes were compared. The impacts of molar ratios of Na2O/SiO2, SiO2/Al2O3, and NaF/SiO2 in the synthetic solution on the preparation of mordenite zeolite membranes under intermittent hydrothermal synthesis were investigated. The as-synthesized mordenite zeolite membrane showed maximum pervaporation performance for isopropanol dehydration under optimized synthetic solution composition with the molar ratios of Na2O/SiO2, SiO2/Al2O3, and NaF/SiO2 were 0.24, 16.7 and 0.25, respectively. The maximum water permeation flux was 5.60 kg·m-2·h-1 and the separation factor was greater than 10 000, respectively, in the dehydration of isopropanol/water mixture (9∶1, w/w) at 75 ℃.
2024, 40(2): 325-335
doi: 10.11862/CJIC.20230290
Abstract:
Inexpensive sulfur-doped porous carbons (SSC-T, T ℃ represented carbonization temperature) were prepared through the hard template method by using inexpensive colloidal silica as a template, sucrose as a carbon source, and sulfuric acid as a precarbonization reagent and sulfur source. The effects of sulfuric acid and carbonization temperature on the microstructure, pore structure, and specific surface area of porous carbons were investigated. It was found that the carbonization temperature had a significant impact on the pore structure, surface area, and sulfur content of carbons. The sample SSC - 900 obtained by carbonization at 900 ℃ has the largest surface area, pore volume, and specific capacitance, which was much higher than the SC-900 prepared without the addition of sulfuric acid, indicating that the addition of sulfuric acid can increase the surface area, pore volume, and the specific capacitance. SSC-900 had the advantages of lower cost, larger pore size, and better capacitive performance than the expensive mesoporous carbon CMK-3. In the three-electrode system with 6.0 mol·L-1 KOH as electrolyte, the specific capacitance of SSC-900 can reach 357 F·g-1 at a current density of 0.5 A·g-1, while the specific capacitance of SC-900 and CMK-3 was only 152 and 266 F·g-1, respectively. The capacitance contribution analysis showed that the doublelayer capacitance (EDLC) and pseudocapacitance of SSC - 900 were higher than those of SC - 900. In addition, SSC-900 can maintain an initial specific capacitance of 98.4% after 10 000 cycles at a current density of 0.5 A·g-1.
Inexpensive sulfur-doped porous carbons (SSC-T, T ℃ represented carbonization temperature) were prepared through the hard template method by using inexpensive colloidal silica as a template, sucrose as a carbon source, and sulfuric acid as a precarbonization reagent and sulfur source. The effects of sulfuric acid and carbonization temperature on the microstructure, pore structure, and specific surface area of porous carbons were investigated. It was found that the carbonization temperature had a significant impact on the pore structure, surface area, and sulfur content of carbons. The sample SSC - 900 obtained by carbonization at 900 ℃ has the largest surface area, pore volume, and specific capacitance, which was much higher than the SC-900 prepared without the addition of sulfuric acid, indicating that the addition of sulfuric acid can increase the surface area, pore volume, and the specific capacitance. SSC-900 had the advantages of lower cost, larger pore size, and better capacitive performance than the expensive mesoporous carbon CMK-3. In the three-electrode system with 6.0 mol·L-1 KOH as electrolyte, the specific capacitance of SSC-900 can reach 357 F·g-1 at a current density of 0.5 A·g-1, while the specific capacitance of SC-900 and CMK-3 was only 152 and 266 F·g-1, respectively. The capacitance contribution analysis showed that the doublelayer capacitance (EDLC) and pseudocapacitance of SSC - 900 were higher than those of SC - 900. In addition, SSC-900 can maintain an initial specific capacitance of 98.4% after 10 000 cycles at a current density of 0.5 A·g-1.
2024, 40(2): 336-344
doi: 10.11862/CJIC.20230266
Abstract:
Enantiomeric lactic derivatives and 3-bromo-4-hydroxybenzoate were used as starting materials to obtain a pair of enantiomers 3-bromo-4-(((1R)-1-carboxyethyl)oxy)benzoic acid (R-H2bba) and 3-bromo-4-(((1S)-1-carboxy-ethyl)oxy)benzoic acid (S-H2bba). As new synthons, R-H2bba and S-H2bba can provide variable coordination modes by two carboxylate groups and chiral source by lactate unit. In the presence of 1, 3-di(pyridine-4-yl)propane (1, 3-dpp), R-H2bba and S-H2bba further assembled with Ni2+ ions under the hydrothermal condition to obtain a pair of chiral coordination polymers (CCPs) {[Ni(R-bba)(1, 3-dpp)(H2O)0.5]·1.5H2O}n (HU12-R) and {[Ni(S-bba) (1, 3-dpp) (H2O)0.5]·1.5H2O}n (HU12-S), respectively. Structural analysis revealed complexes HU12-R and HU12-S are 3D helical frameworks with 4-connected dia net. In complexes HU12-R and HU12-S, R-bba2- and S-bba2- anions are respectively connected by Ni2+ centers to form a pair of small enantiomeric helical chains around 21 screw axis. In contrast, 1, 3-dpp ligands and Ni2+ centers construct another pair of large enantiomeric helical chains around 41 or 43 screw axis, respectively. Moreover, the results of electrochemical testing indicated that complex HU12-R is an n-type semiconductor and has a strong absorbing ability for UV-Vis light and low resistance in charge transportation. By comparing with R-H2bba, 1, 3-dpp, and Ni2+ ions, HU12-R indicates obvious catalytic activity in the degradation of dyes under ultraviolet light.
Enantiomeric lactic derivatives and 3-bromo-4-hydroxybenzoate were used as starting materials to obtain a pair of enantiomers 3-bromo-4-(((1R)-1-carboxyethyl)oxy)benzoic acid (R-H2bba) and 3-bromo-4-(((1S)-1-carboxy-ethyl)oxy)benzoic acid (S-H2bba). As new synthons, R-H2bba and S-H2bba can provide variable coordination modes by two carboxylate groups and chiral source by lactate unit. In the presence of 1, 3-di(pyridine-4-yl)propane (1, 3-dpp), R-H2bba and S-H2bba further assembled with Ni2+ ions under the hydrothermal condition to obtain a pair of chiral coordination polymers (CCPs) {[Ni(R-bba)(1, 3-dpp)(H2O)0.5]·1.5H2O}n (HU12-R) and {[Ni(S-bba) (1, 3-dpp) (H2O)0.5]·1.5H2O}n (HU12-S), respectively. Structural analysis revealed complexes HU12-R and HU12-S are 3D helical frameworks with 4-connected dia net. In complexes HU12-R and HU12-S, R-bba2- and S-bba2- anions are respectively connected by Ni2+ centers to form a pair of small enantiomeric helical chains around 21 screw axis. In contrast, 1, 3-dpp ligands and Ni2+ centers construct another pair of large enantiomeric helical chains around 41 or 43 screw axis, respectively. Moreover, the results of electrochemical testing indicated that complex HU12-R is an n-type semiconductor and has a strong absorbing ability for UV-Vis light and low resistance in charge transportation. By comparing with R-H2bba, 1, 3-dpp, and Ni2+ ions, HU12-R indicates obvious catalytic activity in the degradation of dyes under ultraviolet light.
2024, 40(2): 345-352
doi: 10.11862/CJIC.20230260
Abstract:
Near-infrared phosphor has shown an important application prospect in the fields of living organism imaging. However, the near-infrared phosphor for organism imaging has some bottleneck problems such as a lack of variety and poor thermal stability. Broadband near-infrared Ca4HfGe3O12∶xCr3+ (0≤x≤0.09) phosphors were synthesized by the solid phase method. X-ray diffraction and energy spectrum analysis showed that Cr3+ ions successfully entered the Ca4HfGe3O12 crystal lattice. Upon 469 nm excitation, Ca4HfGe3O12∶xCr3+ phosphors presented a width emission band covering 690-1 200 nm (strongest peak of 825 nm for 4T2-4A2, bandwidth of 141 nm) with a fluorescence quantum efficiency of 33.63% (x=0.03), which exhibited good thermal stability, 60.5% of room temperature intensity at 400 K. The excitation peak shape and lifetime decay behavior results showed that Cr3+ occupies only one cation sites in the matrix. In addition, the self-made near-infrared phosphor conversion device was used to illuminate the palm of the human hand and the fruit shielded by the 700 nm filter, and the venous vessels and the shelter-fruit outline were clearly observed.
Near-infrared phosphor has shown an important application prospect in the fields of living organism imaging. However, the near-infrared phosphor for organism imaging has some bottleneck problems such as a lack of variety and poor thermal stability. Broadband near-infrared Ca4HfGe3O12∶xCr3+ (0≤x≤0.09) phosphors were synthesized by the solid phase method. X-ray diffraction and energy spectrum analysis showed that Cr3+ ions successfully entered the Ca4HfGe3O12 crystal lattice. Upon 469 nm excitation, Ca4HfGe3O12∶xCr3+ phosphors presented a width emission band covering 690-1 200 nm (strongest peak of 825 nm for 4T2-4A2, bandwidth of 141 nm) with a fluorescence quantum efficiency of 33.63% (x=0.03), which exhibited good thermal stability, 60.5% of room temperature intensity at 400 K. The excitation peak shape and lifetime decay behavior results showed that Cr3+ occupies only one cation sites in the matrix. In addition, the self-made near-infrared phosphor conversion device was used to illuminate the palm of the human hand and the fruit shielded by the 700 nm filter, and the venous vessels and the shelter-fruit outline were clearly observed.
2024, 40(2): 353-360
doi: 10.11862/CJIC.2023.189
Abstract:
A turn-on fluorescent probe (HL2) for visual detection of N2H4 was synthesized and characterized using benzoxazole as a fluorophore, and its spectral properties were investigated. The experimental results indicated that HL2 had high selectivity and sensitivity to N2H4, strong anti-interference ability, and a wide pH response range (5-10). HL2 quickly recognized N2H4 within 2 min, accompanied by a color change of the probe solution from colorless to blue. The fluorescent intensity of HL2 showed excellent linear relationship with the concentration of N2H4 (0.1-25 μmol·L-1), and its detection limit was evaluated to be 0.072 μmol·L-1. In addition, HL2 can be applied to detecting N2H4 in real water samples, and it could also realize fluorescence imaging of N2H4 in HeLa cells.
A turn-on fluorescent probe (HL2) for visual detection of N2H4 was synthesized and characterized using benzoxazole as a fluorophore, and its spectral properties were investigated. The experimental results indicated that HL2 had high selectivity and sensitivity to N2H4, strong anti-interference ability, and a wide pH response range (5-10). HL2 quickly recognized N2H4 within 2 min, accompanied by a color change of the probe solution from colorless to blue. The fluorescent intensity of HL2 showed excellent linear relationship with the concentration of N2H4 (0.1-25 μmol·L-1), and its detection limit was evaluated to be 0.072 μmol·L-1. In addition, HL2 can be applied to detecting N2H4 in real water samples, and it could also realize fluorescence imaging of N2H4 in HeLa cells.
2024, 40(2): 361-372
doi: 10.11862/CJIC.20230230
Abstract:
In this work, the electronic structure of three ferrites, Fe2O3 (hematite), Fe3O4 (magnetite), and α-FeOOH (goethite), have been calculated with the density functional theory (DFT) under external electric field (E) for investigating the effect of the external electric field on the electronic structure of ferrites. It was found that the external electric field could continue to decrease the band gap by 0.36, 0.12, and 0.34 eV under an E of 0.01 V·nm-1 through signally changing the valance band maximum. When it increased to 0.1 V·nm-1, Fe2O3 would be broken down by the external electronic field, causing a breaking of the Fe—O bond and a delocalization among Fe atoms along the E direction. At the same time, Fe3O4 and α-FeOOH could maintain their crystal with some effect on the localization and energy of the electron. In addition, it showed a degeneration of the valance electron for three ferrites under the external electric field. For Fe2O3, the Hirshfeld charge of the Fe atoms was reduced while improved for the O atoms along with an increase in the external electronic field. Interestingly, the Hirshfeld charge for both Fe atoms with the form charge of +2 and +3 in Fe3O4 was not influenced by the external electronic field. As for α-FeOOH, the unit of FeO6 located on the edge of the chain was more sensitive than that of the body FeO6 in the chain towards the external electronic field. Meanwhile, the H atom of the terminated -OH in α-FeOOH exhibited a disproportionated response on the Hirshfeld charge under the external electronic field. With the spin of electrons in ferrites, increasing the external electronic field would improve the spin of electrons in Fe3O4 while reducing it in α-FeOOH among an E of 0.001-0.1 V·nm-1.
In this work, the electronic structure of three ferrites, Fe2O3 (hematite), Fe3O4 (magnetite), and α-FeOOH (goethite), have been calculated with the density functional theory (DFT) under external electric field (E) for investigating the effect of the external electric field on the electronic structure of ferrites. It was found that the external electric field could continue to decrease the band gap by 0.36, 0.12, and 0.34 eV under an E of 0.01 V·nm-1 through signally changing the valance band maximum. When it increased to 0.1 V·nm-1, Fe2O3 would be broken down by the external electronic field, causing a breaking of the Fe—O bond and a delocalization among Fe atoms along the E direction. At the same time, Fe3O4 and α-FeOOH could maintain their crystal with some effect on the localization and energy of the electron. In addition, it showed a degeneration of the valance electron for three ferrites under the external electric field. For Fe2O3, the Hirshfeld charge of the Fe atoms was reduced while improved for the O atoms along with an increase in the external electronic field. Interestingly, the Hirshfeld charge for both Fe atoms with the form charge of +2 and +3 in Fe3O4 was not influenced by the external electronic field. As for α-FeOOH, the unit of FeO6 located on the edge of the chain was more sensitive than that of the body FeO6 in the chain towards the external electronic field. Meanwhile, the H atom of the terminated -OH in α-FeOOH exhibited a disproportionated response on the Hirshfeld charge under the external electronic field. With the spin of electrons in ferrites, increasing the external electronic field would improve the spin of electrons in Fe3O4 while reducing it in α-FeOOH among an E of 0.001-0.1 V·nm-1.
2024, 40(2): 373-382
doi: 10.11862/CJIC.2023.208
Abstract:
Herein, tungsten disulfide (WS2) nanosheets were firstly prepared by ultrasonic stripping method. Subsequently, the mixture of WS2 nanosheets and P powder were treated by the Ar plasma, obtaining P-doped defective WS2 nanosheets (P-D-WS2 NSs). The as-prepared P-D-WS2 NSs samples exhibited higher catalytic activity for hydrogen evolution reaction (HER) than defective WS2 nanosheets and pure WS2 nanosheets, such as lower overpotential, smaller Tafel slope, and better durability. Density functional theory calculations showed that the P atoms and defective structures in WS2 regulated the electronic environment around the materials, optimizing the energy barrier of H+ adsorption and hydrogen formation kinetics performance, thus improving the HER electrocatalytic activity.
Herein, tungsten disulfide (WS2) nanosheets were firstly prepared by ultrasonic stripping method. Subsequently, the mixture of WS2 nanosheets and P powder were treated by the Ar plasma, obtaining P-doped defective WS2 nanosheets (P-D-WS2 NSs). The as-prepared P-D-WS2 NSs samples exhibited higher catalytic activity for hydrogen evolution reaction (HER) than defective WS2 nanosheets and pure WS2 nanosheets, such as lower overpotential, smaller Tafel slope, and better durability. Density functional theory calculations showed that the P atoms and defective structures in WS2 regulated the electronic environment around the materials, optimizing the energy barrier of H+ adsorption and hydrogen formation kinetics performance, thus improving the HER electrocatalytic activity.
2024, 40(2): 383-393
doi: 10.11862/CJIC.20230189
Abstract:
Perovskite CsPbBr3-Fe quantum dots (QDs) with good dispersion and uniform size were prepared using a simple solution route combined with an acetylacetone iron (AAI) modification technology. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and photoluminescence (PL) spectroscopy. Then, a resistive humidity sensor was fabricated with the perovskite CsPbBr3-Fe QDs by a spin-coating method. The humidity sensitivity measurement results showed that the device had good linear and rapid response characteristics with a detection range of 10% to 100% relative humidity (RH). At 70% RH, the humid sensor displayed a sensitivity of 1.1, a response time of 38 s, and a recovery time of 38 s, respectively. In addition, we used the finite element method (FEM) to simulate the leakage behavior of pipeline microcracks, and verified the feasibility of using humidity sensors to detect the leakage locations by simulating the distribution of flow velocity and pressure fields under different flow velocities and pressures.
Perovskite CsPbBr3-Fe quantum dots (QDs) with good dispersion and uniform size were prepared using a simple solution route combined with an acetylacetone iron (AAI) modification technology. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and photoluminescence (PL) spectroscopy. Then, a resistive humidity sensor was fabricated with the perovskite CsPbBr3-Fe QDs by a spin-coating method. The humidity sensitivity measurement results showed that the device had good linear and rapid response characteristics with a detection range of 10% to 100% relative humidity (RH). At 70% RH, the humid sensor displayed a sensitivity of 1.1, a response time of 38 s, and a recovery time of 38 s, respectively. In addition, we used the finite element method (FEM) to simulate the leakage behavior of pipeline microcracks, and verified the feasibility of using humidity sensors to detect the leakage locations by simulating the distribution of flow velocity and pressure fields under different flow velocities and pressures.
2024, 40(2): 394-404
doi: 10.11862/CJIC.20230171
Abstract:
To investigate the relationship between the fracture failure and the initial microstructure of the hollow nanowires (NW), a series of spherical hollow structures were constructed and molecular dynamics (MD) simulations were performed with 300 samples that have different initial states. The position of the initial slip plane was obtained using the density-based spatial clustering of applications with noise (DBSCAN) machine learning algorithm. Based on big data analysis, the distribution of the initial slip position and the fracture position were analyzed. The result of the correlation between the two shows that when the inner hollow radius is small, the distribution of fracture posi- tions is formed during the plastic deformation stage, so there is no correlation between the distribution of initial slip and fracture positions. However, for brittle NW with significantly larger hollow radii, the slip plane induced by the high -energy inner surface quickly accumulates, resulting in necking and ultimately fracture. Therefore, when the internal hollow structure reaches a certain size, there is a clear causal relationship between the distribution of initial slip positions and the distribution of final fracture positions.
To investigate the relationship between the fracture failure and the initial microstructure of the hollow nanowires (NW), a series of spherical hollow structures were constructed and molecular dynamics (MD) simulations were performed with 300 samples that have different initial states. The position of the initial slip plane was obtained using the density-based spatial clustering of applications with noise (DBSCAN) machine learning algorithm. Based on big data analysis, the distribution of the initial slip position and the fracture position were analyzed. The result of the correlation between the two shows that when the inner hollow radius is small, the distribution of fracture posi- tions is formed during the plastic deformation stage, so there is no correlation between the distribution of initial slip and fracture positions. However, for brittle NW with significantly larger hollow radii, the slip plane induced by the high -energy inner surface quickly accumulates, resulting in necking and ultimately fracture. Therefore, when the internal hollow structure reaches a certain size, there is a clear causal relationship between the distribution of initial slip positions and the distribution of final fracture positions.
2024, 40(2): 405-411
doi: 10.11862/CJIC.20230149
Abstract:
K+ doped double perovskite Cs2AgInCl6 nanomaterial was prepared by solid phase ball milling method, which is environmentally friendly without ligands. The crystal structure was studied by X-ray diffraction and Raman spectrum, and the luminescence properties were studied by excitation spectrum, emission spectrum, and time-resolved spectrum. The results show that the Cs2AgInCl6 is a cubic crystal, which belongs to Fm3m space group. Due to parity-forbidden transition, the photoluminescence quantum yield (PLQY) is low, less than 0.1%. When K+ doping is less than 60%, it mainly replaces Ag+, which causes lattice expansion of Cs2AgInCl6, eliminates inversion symmetry of lattice structure, breaks parity forbidden transition, and enhances photoluminescence intensity of Cs2AgInCl6. The optimal doping ratio was 40%, the center wavelength of Cs2Ag0.6K0.4InCl6 was 640 nm, the half-height width was 180 nm, the average fluorescence lifetime was 29.2 ns and the PLQY reached 10.5%. When the doping ratio of K+ exceeds 60%, K+ begins to replace the position of Cs+, which results in the presence of cubic phase Cs2-xK1+x-yAgyInCl6 and monoclinic phase Cs2-xK1+xInCl6. These products are dominated by non-radiative recombination due to strong electron-phonon coupling.
K+ doped double perovskite Cs2AgInCl6 nanomaterial was prepared by solid phase ball milling method, which is environmentally friendly without ligands. The crystal structure was studied by X-ray diffraction and Raman spectrum, and the luminescence properties were studied by excitation spectrum, emission spectrum, and time-resolved spectrum. The results show that the Cs2AgInCl6 is a cubic crystal, which belongs to Fm3m space group. Due to parity-forbidden transition, the photoluminescence quantum yield (PLQY) is low, less than 0.1%. When K+ doping is less than 60%, it mainly replaces Ag+, which causes lattice expansion of Cs2AgInCl6, eliminates inversion symmetry of lattice structure, breaks parity forbidden transition, and enhances photoluminescence intensity of Cs2AgInCl6. The optimal doping ratio was 40%, the center wavelength of Cs2Ag0.6K0.4InCl6 was 640 nm, the half-height width was 180 nm, the average fluorescence lifetime was 29.2 ns and the PLQY reached 10.5%. When the doping ratio of K+ exceeds 60%, K+ begins to replace the position of Cs+, which results in the presence of cubic phase Cs2-xK1+x-yAgyInCl6 and monoclinic phase Cs2-xK1+xInCl6. These products are dominated by non-radiative recombination due to strong electron-phonon coupling.
2024, 40(2): 412-420
doi: 10.11862/CJIC.20230288
Abstract:
Using triblock copolymer P123 (poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide), PEO20-PPO70-PEO20) as reducing agent and protective agent, the effects of hydrothermal and solvothermal methods on the synthesis of pure Ir and IrPd alloy catalysts and their electrocatalytic oxidation of methanol (MOR) were compared. For pure Ir catalyst, solvothermal method can better promote the reduction of Ir precursor under the same condi- tions. For IrPd alloy catalysts, core-shell structure products (IrPd-S) with rich Ir-surface but low MOR activity can be prepared by solvothermal method. The different atomic ratios (IrPd, Ir2Pd, IrPd2) obtained by hydrothermal reaction have smaller particle sizes and more uniform distribution of elements. Among them, IrPd catalyst with ratio of 1∶1 (IrPd-H) had the highest MOR electrocatalytic activity. These results show that the structure, surface composition and electrocatalytic activity of pure Ir and IrPd alloy catalysts can be effectively adjusted by adjusting the type of solvent and the structural induction of P123.
Using triblock copolymer P123 (poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide), PEO20-PPO70-PEO20) as reducing agent and protective agent, the effects of hydrothermal and solvothermal methods on the synthesis of pure Ir and IrPd alloy catalysts and their electrocatalytic oxidation of methanol (MOR) were compared. For pure Ir catalyst, solvothermal method can better promote the reduction of Ir precursor under the same condi- tions. For IrPd alloy catalysts, core-shell structure products (IrPd-S) with rich Ir-surface but low MOR activity can be prepared by solvothermal method. The different atomic ratios (IrPd, Ir2Pd, IrPd2) obtained by hydrothermal reaction have smaller particle sizes and more uniform distribution of elements. Among them, IrPd catalyst with ratio of 1∶1 (IrPd-H) had the highest MOR electrocatalytic activity. These results show that the structure, surface composition and electrocatalytic activity of pure Ir and IrPd alloy catalysts can be effectively adjusted by adjusting the type of solvent and the structural induction of P123.
2024, 40(2): 421-429
doi: 10.11862/CJIC.20230277
Abstract:
Two analogous binuclear coordination complexes derived from nitronyl nitroxide radical ligands have been synthesized. Their general formulae are [Mn2(hfac)4(NIT-mo-pmy)2] (1) and [Co2(hfac)4(NIT-mo-pmy)2] (2), respectively, where hfac=hexafluoroacetylacetone and NIT-mo-pmy=2-(2-methoxy-5′-pyrimidinyl)-4,4,5,5-tetra-methyl-imidazoline-3-oxy-1-oxyl radical. Both complexes crystallize in a triclinic system P1 space group, exhibiting a centrosymmetric rectangle-like array based on dimer coordination units. Variable-temperature magnetic characterizations reveal the presence of antiferromagnetic exchanges between central ions and nitroxide radicals in both fourspin nitroxide radical complexes. The different strengths of both complexes were investigated based on structure-property relationship analysis. The magnetic behaviors of the Mn (Ⅱ) complex have been quantitatively evaluated through an appropriate magnetic model and were compared with the relevant complexes.
Two analogous binuclear coordination complexes derived from nitronyl nitroxide radical ligands have been synthesized. Their general formulae are [Mn2(hfac)4(NIT-mo-pmy)2] (1) and [Co2(hfac)4(NIT-mo-pmy)2] (2), respectively, where hfac=hexafluoroacetylacetone and NIT-mo-pmy=2-(2-methoxy-5′-pyrimidinyl)-4,4,5,5-tetra-methyl-imidazoline-3-oxy-1-oxyl radical. Both complexes crystallize in a triclinic system P1 space group, exhibiting a centrosymmetric rectangle-like array based on dimer coordination units. Variable-temperature magnetic characterizations reveal the presence of antiferromagnetic exchanges between central ions and nitroxide radicals in both fourspin nitroxide radical complexes. The different strengths of both complexes were investigated based on structure-property relationship analysis. The magnetic behaviors of the Mn (Ⅱ) complex have been quantitatively evaluated through an appropriate magnetic model and were compared with the relevant complexes.
2024, 40(2): 430-440
doi: 10.11862/CJIC.20230263
Abstract:
A mild and efficient method for continuous transfer hydrogenation of nitroaromatics catalyzed by Ru-Fe bimetallic catalyst with methanol as hydrogen source was developed. Ru-Fe bimetallic catalysts were prepared by impregnation method and characterized by inductively coupled plasma-mass spectrometry (ICP-MS), transmission electron microscopy (TEM), X-ray diffraction (XRD), and hydrogen temperature-programmed reduction (H2-TPR). The results showed that the catalyst had smaller particle size and better dispersion. On the Ru-Fe bimetallic catalyst, the continuous transfer hydrogenation of nitroaromatics and methanol to aromatic amines without external hydrogenation source was successfully realized. A series of amines with high yields were successfully obtained by adjusting the reaction conditions. In particular, the method exhibited excellent selectivity and conversion for the hydrogenation of unsaturated group (aldehyde, carbonyl or alkynyl) substituted nitroaromatics.
A mild and efficient method for continuous transfer hydrogenation of nitroaromatics catalyzed by Ru-Fe bimetallic catalyst with methanol as hydrogen source was developed. Ru-Fe bimetallic catalysts were prepared by impregnation method and characterized by inductively coupled plasma-mass spectrometry (ICP-MS), transmission electron microscopy (TEM), X-ray diffraction (XRD), and hydrogen temperature-programmed reduction (H2-TPR). The results showed that the catalyst had smaller particle size and better dispersion. On the Ru-Fe bimetallic catalyst, the continuous transfer hydrogenation of nitroaromatics and methanol to aromatic amines without external hydrogenation source was successfully realized. A series of amines with high yields were successfully obtained by adjusting the reaction conditions. In particular, the method exhibited excellent selectivity and conversion for the hydrogenation of unsaturated group (aldehyde, carbonyl or alkynyl) substituted nitroaromatics.
2024, 40(2): 441-450
doi: 10.11862/CJIC.20230145
Abstract:
The isomorphic terbium and europium coordination polymers (CPs) {[Eu(PLIA)1.5(H2O)2] ·H2O}n (1) and {[Tb(PLIA)1.5(H2O)2]·H2O}n (2), where H2PLIA=5-((pyridin-4-yl-methyl)oxy)benzene-1,3-dicarboxylic acid, were synthesized by using aromatic π-conjugated and nitrogen-containing organic linkers. The structure determination, characterization, and fluorescence trace identification of the CPs were studied. The two isomorphic complexes have an ideal 3D frame structure and their chemical stability is enhanced by weak interactions such as π…π packing and hydrogen bonds. The characterization shows that CPs 1 and 2 have good fluorescence deletion properties, crystallinity, thermodynamic stability, and structural integrity, and can be used as fluorescence sensing materials. 1 and 2 have fluorescence recognition ability for Zr4+, Cr2O72- and Fe3+, HPO42- in aqueous solution, respectively, with good selectivity and high sensitivity. The detection limits of these four ions by 1 and 2 were 0.139 μmol·L-1 (1, Zr4+), 0.626 μmol·L-1 (1, Cr2O72-), 0.430 μmol·L-1 (2, Fe3+), 1.36 μmol·L-1 (2, HPO42-), respectively. The fluorescence quenching mechanism of 1 and 2 as probes was investigated in detail. More interestingly, the two complexes have potential fingerprint recognition properties. Their fluorescent fingerprint patterns were clear and coherent, and the details were obvious and could be clearly observed.
The isomorphic terbium and europium coordination polymers (CPs) {[Eu(PLIA)1.5(H2O)2] ·H2O}n (1) and {[Tb(PLIA)1.5(H2O)2]·H2O}n (2), where H2PLIA=5-((pyridin-4-yl-methyl)oxy)benzene-1,3-dicarboxylic acid, were synthesized by using aromatic π-conjugated and nitrogen-containing organic linkers. The structure determination, characterization, and fluorescence trace identification of the CPs were studied. The two isomorphic complexes have an ideal 3D frame structure and their chemical stability is enhanced by weak interactions such as π…π packing and hydrogen bonds. The characterization shows that CPs 1 and 2 have good fluorescence deletion properties, crystallinity, thermodynamic stability, and structural integrity, and can be used as fluorescence sensing materials. 1 and 2 have fluorescence recognition ability for Zr4+, Cr2O72- and Fe3+, HPO42- in aqueous solution, respectively, with good selectivity and high sensitivity. The detection limits of these four ions by 1 and 2 were 0.139 μmol·L-1 (1, Zr4+), 0.626 μmol·L-1 (1, Cr2O72-), 0.430 μmol·L-1 (2, Fe3+), 1.36 μmol·L-1 (2, HPO42-), respectively. The fluorescence quenching mechanism of 1 and 2 as probes was investigated in detail. More interestingly, the two complexes have potential fingerprint recognition properties. Their fluorescent fingerprint patterns were clear and coherent, and the details were obvious and could be clearly observed.
2024, 40(2): 451-462
doi: 10.11862/CJIC.20230090
Abstract:
Using a green synthesis method, Salvia officinalis extract was used as a reducing and capping agent to synthesize nickel oxide nanoparticles (NiO NPs). In addition, NiO NPs were synthesized using various precursors, and their morphologies were analyzed using scanning electron microscopy. The structures of NiO NPs were characterized using Fourier-transform infrared spectroscopy, and powder X-ray diffraction (PXRD). Their magnetic properties were measured using a vibrating sample magnetometer. PXRD studies showed that all synthesized NiO NPs exhibited a face-centered cubic phase with high crystallinity, and NiO formations with a high-purity phase were confirmed. As a result of magnetization studies, NiO NPs synthesized from three nickel salt precursors (acetate, chloride, and sulfate) exhibit superparamagnetic, soft ferromagnetic, and paramagnetic behaviors, respectively.
Using a green synthesis method, Salvia officinalis extract was used as a reducing and capping agent to synthesize nickel oxide nanoparticles (NiO NPs). In addition, NiO NPs were synthesized using various precursors, and their morphologies were analyzed using scanning electron microscopy. The structures of NiO NPs were characterized using Fourier-transform infrared spectroscopy, and powder X-ray diffraction (PXRD). Their magnetic properties were measured using a vibrating sample magnetometer. PXRD studies showed that all synthesized NiO NPs exhibited a face-centered cubic phase with high crystallinity, and NiO formations with a high-purity phase were confirmed. As a result of magnetization studies, NiO NPs synthesized from three nickel salt precursors (acetate, chloride, and sulfate) exhibit superparamagnetic, soft ferromagnetic, and paramagnetic behaviors, respectively.
