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2021 Volume 37 Issue 11
2021, 37(11): 1913-1921
doi: 10.11862/CJIC.2021.232
Abstract:
Three new 3D microporous isostructural heterometallic metal organic frameworks Ln(Na)-MOFs: {[LnNa(BDT)(H2O)3]·2H2O}n (Ln=Tb (1), Dy (2), Ho (3), H4BDT=3, 5-bis(3', 5'-dicarboxylphenyl)-1H-1, 2, 4-triazole), have been synthesized under solvothermal condition, and characterized by single crystal X-ray diffraction, elemental analysis, thermogravimetric analysis, and powder X-ray diffraction. Structural analysis demonstrates that they possess the same 3D frameworks based on similar heteronuclear bimetallic units. Fluorescence studies show that Tb (Na)-MOF (1) can detect Fe3+ ion, Cr2O72- anion, and acetaldehyde molecules with high sensitivity and selectivity by luminescent sensing, and can also be used for electrochemical detection of catechol in water.
Three new 3D microporous isostructural heterometallic metal organic frameworks Ln(Na)-MOFs: {[LnNa(BDT)(H2O)3]·2H2O}n (Ln=Tb (1), Dy (2), Ho (3), H4BDT=3, 5-bis(3', 5'-dicarboxylphenyl)-1H-1, 2, 4-triazole), have been synthesized under solvothermal condition, and characterized by single crystal X-ray diffraction, elemental analysis, thermogravimetric analysis, and powder X-ray diffraction. Structural analysis demonstrates that they possess the same 3D frameworks based on similar heteronuclear bimetallic units. Fluorescence studies show that Tb (Na)-MOF (1) can detect Fe3+ ion, Cr2O72- anion, and acetaldehyde molecules with high sensitivity and selectivity by luminescent sensing, and can also be used for electrochemical detection of catechol in water.
2021, 37(11): 2047-2058
doi: 10.11862/CJIC.2021.224
Abstract:
Two complexes with chemical formulas[Co(L)2(H2O)4]·2H2O (1) and[Cd(L)2(H2O)]·3H2O (2) were obtained by the reaction of 3-carboxy-1-(4-carboxybenzyl)-pyridinium bromide ((H2L) Br) with corresponding Co(Ⅱ) and Cd(Ⅱ) metal salts. Crystal structure analysis reveals that 1 is a neutral mononuclear complex, which possesses abundant hydrogen bond and π-π interaction components and can be used as supramolecular synthons. In the case of 1, mononuclear[Co(L)2(H2O)4] coordination entities are first joined via hydrogen bonding to produce channel-structured 2D layers, which are further stacked via π-π stacking effect in an interdigitating fashion, generating a 3D porous supramolecular assembly. 2 features a polymeric 1D zigzag chain structure, which is connected via π-π interactions between pendent L ligands, resulting in the formation of 1D ladder chains. Such 1D ladder chains are further combined into wave-like 2D sheets via another two kinds of π-π stacking between two adjacent side rails of 1D ladder chains. Such 2D sheets are further assembled via eight types of O-H…O hydrogen bonds to form a 3D supramolecular structure. According to topological viewpoint based on 1D chains, the 3D structure of 2 can also be deemed as the plywood-like array. In addition, 2 shows strong ultraviolet fluorescence emission with an average life-time of 2.54 ns.
Two complexes with chemical formulas[Co(L)2(H2O)4]·2H2O (1) and[Cd(L)2(H2O)]·3H2O (2) were obtained by the reaction of 3-carboxy-1-(4-carboxybenzyl)-pyridinium bromide ((H2L) Br) with corresponding Co(Ⅱ) and Cd(Ⅱ) metal salts. Crystal structure analysis reveals that 1 is a neutral mononuclear complex, which possesses abundant hydrogen bond and π-π interaction components and can be used as supramolecular synthons. In the case of 1, mononuclear[Co(L)2(H2O)4] coordination entities are first joined via hydrogen bonding to produce channel-structured 2D layers, which are further stacked via π-π stacking effect in an interdigitating fashion, generating a 3D porous supramolecular assembly. 2 features a polymeric 1D zigzag chain structure, which is connected via π-π interactions between pendent L ligands, resulting in the formation of 1D ladder chains. Such 1D ladder chains are further combined into wave-like 2D sheets via another two kinds of π-π stacking between two adjacent side rails of 1D ladder chains. Such 2D sheets are further assembled via eight types of O-H…O hydrogen bonds to form a 3D supramolecular structure. According to topological viewpoint based on 1D chains, the 3D structure of 2 can also be deemed as the plywood-like array. In addition, 2 shows strong ultraviolet fluorescence emission with an average life-time of 2.54 ns.
2021, 37(11): 2059-2067
doi: 10.11862/CJIC.2021.229
Abstract:
Controlling the distribution of metal nanoparticles in metal@MOF core-shell structures is not easy to realize. We applied the coordination modulation method which has been studied in the synthesis of MOF colloids to synthesize Au@ZIF-8 core-shell nanostructures. Different Au@ZIF-8 core-shell nanostructures have been achieved by employing an excess amount of 2-methylimidazole and various amount of 1-methylimidazole. With our method, the distribution of Au nanoparticles (Au NPs) could be flexibly tuned in the ZIF-8 nanocrystals. Moreover, we investigated the photoluminescent spectra and lifetime of two fluorescent molecules with different sizes, combined with Au@ZIF-8 separately. The aperture size of ZIF-8 determines whether to let the molecules pass through the porous shell to approach Au NPs, and the molecular optical properties are sensitive to the competition of luminescent enhancement and fluorescent quenching of Au NPs.
Controlling the distribution of metal nanoparticles in metal@MOF core-shell structures is not easy to realize. We applied the coordination modulation method which has been studied in the synthesis of MOF colloids to synthesize Au@ZIF-8 core-shell nanostructures. Different Au@ZIF-8 core-shell nanostructures have been achieved by employing an excess amount of 2-methylimidazole and various amount of 1-methylimidazole. With our method, the distribution of Au nanoparticles (Au NPs) could be flexibly tuned in the ZIF-8 nanocrystals. Moreover, we investigated the photoluminescent spectra and lifetime of two fluorescent molecules with different sizes, combined with Au@ZIF-8 separately. The aperture size of ZIF-8 determines whether to let the molecules pass through the porous shell to approach Au NPs, and the molecular optical properties are sensitive to the competition of luminescent enhancement and fluorescent quenching of Au NPs.
2021, 37(11): 2068-2078
doi: 10.11862/CJIC.2021.228
Abstract:
3-aminopropyltriethoxysilane (APTES) was introduced to modify the surface of T-type zeolite membranes. Characterizations, such as X-ray diffraction, field-emission scanning electron microscopy, X-ray photoelectron spectroscopy and FT-IR, demonstrated that APTES was successfully modified on the membrane surface by chemical bonding. The modified APTES plays two roles: one is to improve the membrane hydrophilicity and the other is to reduce the defects of membrane layer. The modified membranes showed a high separation factor and water flux for the dewatering of a 90% isopropyl alcohol solution at 348 K. This method showed good reproducibility, and five modified membranes demonstrated an increased separation factor by about 8 times (from 359±23 to 2 934±183), and a slightly decreased total flux from (3.52±0.10) kg·m-2·h-1 to (3.06±0.14) kg·m-2·h-1 (a decrease of 13.07%). At 363 K, during 100 h of continuous testing, the modified membrane was very stable, and the permeation side retained a high-water content above 99.50% with a feed solution of 90% isopropyl alcohol.
3-aminopropyltriethoxysilane (APTES) was introduced to modify the surface of T-type zeolite membranes. Characterizations, such as X-ray diffraction, field-emission scanning electron microscopy, X-ray photoelectron spectroscopy and FT-IR, demonstrated that APTES was successfully modified on the membrane surface by chemical bonding. The modified APTES plays two roles: one is to improve the membrane hydrophilicity and the other is to reduce the defects of membrane layer. The modified membranes showed a high separation factor and water flux for the dewatering of a 90% isopropyl alcohol solution at 348 K. This method showed good reproducibility, and five modified membranes demonstrated an increased separation factor by about 8 times (from 359±23 to 2 934±183), and a slightly decreased total flux from (3.52±0.10) kg·m-2·h-1 to (3.06±0.14) kg·m-2·h-1 (a decrease of 13.07%). At 363 K, during 100 h of continuous testing, the modified membrane was very stable, and the permeation side retained a high-water content above 99.50% with a feed solution of 90% isopropyl alcohol.
2021, 37(11): 2079-2091
doi: 10.11862/CJIC.2021.231
Abstract:
Two new cadmium(Ⅱ) complexes were synthesized by hydrothermal method with 2-(4-carboxy-phenyl)-imidazole-4, 5-dicarboxylic acid (H3L) through the auxiliary ligands 1, 10-phenanthroline(1, 10-phen) and 1, 4-bis(1-imidazolyl) benzene(dib) coordination regulation effect, [Cd2(HL)2(1, 10-phen)2(H2O)2] (1) and {[Cd(HL)(dib)0.5(H2O)2]·2H2O}n (2). 1 and 2 were analyzed and characterized by single crystal X-ray diffraction, element analysis, thermo-gravimetric analysis, powder X-ray diffraction, infrared spectroscopy, Hirshfeld surface analysis, and density functional theory quantification calculations. Single crystal X-ray diffraction shows that 1 and 2 belong to the triclinic system and the P1 space group, and 1 forms a zero-dimensional structure, 2 forms a one-dimensional chain structure.
Two new cadmium(Ⅱ) complexes were synthesized by hydrothermal method with 2-(4-carboxy-phenyl)-imidazole-4, 5-dicarboxylic acid (H3L) through the auxiliary ligands 1, 10-phenanthroline(1, 10-phen) and 1, 4-bis(1-imidazolyl) benzene(dib) coordination regulation effect, [Cd2(HL)2(1, 10-phen)2(H2O)2] (1) and {[Cd(HL)(dib)0.5(H2O)2]·2H2O}n (2). 1 and 2 were analyzed and characterized by single crystal X-ray diffraction, element analysis, thermo-gravimetric analysis, powder X-ray diffraction, infrared spectroscopy, Hirshfeld surface analysis, and density functional theory quantification calculations. Single crystal X-ray diffraction shows that 1 and 2 belong to the triclinic system and the P1 space group, and 1 forms a zero-dimensional structure, 2 forms a one-dimensional chain structure.
2021, 37(11): 2092-2100
doi: 10.11862/CJIC.2021.220
Abstract:
The dehydrated Ni-Fe hydrotalcite-like compounds (Ni-Fe HTLCs) containing nitrate anions were synthesized and applied in furfural acetalization at room temperature. The dehydrated Ni-Fe HTLCs showed good selectivity for furfural acetalization and achieved almost complete conversion of furfural. The dehydrated Ni-Fe HTLCs as water-tolerant Lewis acids and water scavengers was proved to be an efficient bifunctional catalyst for furfural acetalization. The removal of interlayer water leads to shrinkage of Ni-Fe HTLCs particles and increase in electronic repulsion among NO3- ions in the interlayer. The weak acid sites in Ni-Fe HTLCs play an important role in furfural acetalization. The dehydration changes structure of the acid sites and thus improves activity of the weak acid sites. The dehydrated Ni-Fe HTLCs can absorb the most of the resulting water during furfural acetalization, but the structure of Ni-Fe HTLCs cannot completely recover after rehydration possibly due to hindering effect of organic molecules diffusing into interlayer space.
The dehydrated Ni-Fe hydrotalcite-like compounds (Ni-Fe HTLCs) containing nitrate anions were synthesized and applied in furfural acetalization at room temperature. The dehydrated Ni-Fe HTLCs showed good selectivity for furfural acetalization and achieved almost complete conversion of furfural. The dehydrated Ni-Fe HTLCs as water-tolerant Lewis acids and water scavengers was proved to be an efficient bifunctional catalyst for furfural acetalization. The removal of interlayer water leads to shrinkage of Ni-Fe HTLCs particles and increase in electronic repulsion among NO3- ions in the interlayer. The weak acid sites in Ni-Fe HTLCs play an important role in furfural acetalization. The dehydration changes structure of the acid sites and thus improves activity of the weak acid sites. The dehydrated Ni-Fe HTLCs can absorb the most of the resulting water during furfural acetalization, but the structure of Ni-Fe HTLCs cannot completely recover after rehydration possibly due to hindering effect of organic molecules diffusing into interlayer space.
2021, 37(11): 2101-2112
doi: 10.11862/CJIC.2021.237
Abstract:
Utilizing the rigid 6-(3-pyridyl) isophthalic acid (H2PIAD) linker, one Mn(Ⅱ)-based coordination polymer {[Mn(PIAD)(DMF)]·H2O}n (1) was prepared firstly. In order to improve the electrocatalytic activity of glucose sensing, a composite material (Ag@1) was prepared by the strategy of post synthesis of Ag nanoparticles (NPs). The electrocatalytic performance of the glassy carbon electrode (GCE) modified by Ag@1 was evaluated by chronoamperometry method at the optimized application potential, and coordination polymer 1 provided a fixed substrate for the uniform distribution of Ag NPs on its surface. Ag@1 sensor can maximize the electrocatalytic synergistic effect of the combination of Ag and 1 on glucose oxidation. The results reveal that modified GCE by Ag@1 had good performance for the detection of glucose with low detection limit (6.36 μmol·L-1), good selectivity and sensitivity (166.71 μA·L·mmol-1·cm-2).
Utilizing the rigid 6-(3-pyridyl) isophthalic acid (H2PIAD) linker, one Mn(Ⅱ)-based coordination polymer {[Mn(PIAD)(DMF)]·H2O}n (1) was prepared firstly. In order to improve the electrocatalytic activity of glucose sensing, a composite material (Ag@1) was prepared by the strategy of post synthesis of Ag nanoparticles (NPs). The electrocatalytic performance of the glassy carbon electrode (GCE) modified by Ag@1 was evaluated by chronoamperometry method at the optimized application potential, and coordination polymer 1 provided a fixed substrate for the uniform distribution of Ag NPs on its surface. Ag@1 sensor can maximize the electrocatalytic synergistic effect of the combination of Ag and 1 on glucose oxidation. The results reveal that modified GCE by Ag@1 had good performance for the detection of glucose with low detection limit (6.36 μmol·L-1), good selectivity and sensitivity (166.71 μA·L·mmol-1·cm-2).
2021, 37(11): 1922-1930
doi: 10.11862/CJIC.2021.242
Abstract:
The porous carbon nanofiber films (PCNFS) were prepared via electrospinning and sol-gel method using SiO2 as template. Then, a flexible carbon/selenium composite electrode (Se@PCNFS) was obtained by melting and diffusion loading of selenium. The microstructure and morphology of the materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results showed that the porous carbon nanofibers endowed the diameter of about 300 nm and selenium was uniformly dispersed within the fibers. Thus, Se@PCNFS electrode showed outstanding cycling performance and rate performance in lithium-selenium battery. 1Se@PCNFS electrode delivered the initial specific capacity of 569 mAh·g-1 and maintained a reversible capacity of 340 mAh·g-1 after 500 cycles at 0.5C rate. The reversible capacity was 403 mAh·g-1 at 2C rate.
The porous carbon nanofiber films (PCNFS) were prepared via electrospinning and sol-gel method using SiO2 as template. Then, a flexible carbon/selenium composite electrode (Se@PCNFS) was obtained by melting and diffusion loading of selenium. The microstructure and morphology of the materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results showed that the porous carbon nanofibers endowed the diameter of about 300 nm and selenium was uniformly dispersed within the fibers. Thus, Se@PCNFS electrode showed outstanding cycling performance and rate performance in lithium-selenium battery. 1Se@PCNFS electrode delivered the initial specific capacity of 569 mAh·g-1 and maintained a reversible capacity of 340 mAh·g-1 after 500 cycles at 0.5C rate. The reversible capacity was 403 mAh·g-1 at 2C rate.
2021, 37(11): 1931-1942
doi: 10.11862/CJIC.2021.241
Abstract:
A series of X-MOF@GO composited with X-MOF (X6O(TATB)4(H+)2·(H2O)8·(DMF)2, X=Zn, Co, Ni; H3TATB=4, 4', 4″-s-triazine-2, 4, 6-triyl-tribenzoic acid; DMF=N, N-dimethylformamide) and graphene oxide (GO) as supercapacitor electrode materials were synthesized by one-step self-assembly under hydrothermal conditions. X-ray powder diffraction, X-ray photoelectron spectroscopy and scanning electron microscopy showed that X-MOF@GO composites were successfully synthesized. Ni-MOF@1.5GO electrode with the best performance delivered a specific capacitance of 694.8 F·g-1 at 0.5 A·g-1. Moreover, the specific capacitance of Ni-MOF@1.5GO electrode was nearly twice of Ni-MOF, while the capacitance of Ni-MOFs@1.0GO retained about 81.2% after 1 000 cycles indicating that GO doped Ni-MOF can boost the performance of MOFs materials effectively. A symmetrical capacitor based on Ni-MOF@1.5GO//AC (AC=activated carbon) electrode exhibited a high energy density of 754.3 W·kg-1 at power density of 15.4 Wh·kg-1, while the capacitance retention reached about 70.0% after 3 000 cycles.
A series of X-MOF@GO composited with X-MOF (X6O(TATB)4(H+)2·(H2O)8·(DMF)2, X=Zn, Co, Ni; H3TATB=4, 4', 4″-s-triazine-2, 4, 6-triyl-tribenzoic acid; DMF=N, N-dimethylformamide) and graphene oxide (GO) as supercapacitor electrode materials were synthesized by one-step self-assembly under hydrothermal conditions. X-ray powder diffraction, X-ray photoelectron spectroscopy and scanning electron microscopy showed that X-MOF@GO composites were successfully synthesized. Ni-MOF@1.5GO electrode with the best performance delivered a specific capacitance of 694.8 F·g-1 at 0.5 A·g-1. Moreover, the specific capacitance of Ni-MOF@1.5GO electrode was nearly twice of Ni-MOF, while the capacitance of Ni-MOFs@1.0GO retained about 81.2% after 1 000 cycles indicating that GO doped Ni-MOF can boost the performance of MOFs materials effectively. A symmetrical capacitor based on Ni-MOF@1.5GO//AC (AC=activated carbon) electrode exhibited a high energy density of 754.3 W·kg-1 at power density of 15.4 Wh·kg-1, while the capacitance retention reached about 70.0% after 3 000 cycles.
2021, 37(11): 1943-1949
doi: 10.11862/CJIC.2021.222
Abstract:
Using carbon cloth (CC) as a flexible substrate, needle-like network structure NiCo2O4 was grown on the surface of CC by hydrothermal method, and then NiCo2O4@CC composites were prepared and used for lithium-sulfur battery. NiCo2O4 grows vertically on the surface of carbon fiber to form a three-dimensional network of nano-needle clusters, which provides more space for sulfur storage and effectively alleviates the volume expansion of sulfur electrode. Through adsorption experiments, it is proved that NiCo2O4@CC can effectively adsorb polysulfide, thus inhibiting the shuttle effect of polysulfide. Compared with CC/S (933 mAh·g-1), NiCo2O4@CC/S composite had better battery performance. The initial discharge specific capacity was as high as 1 467 mAh·g-1 at 0.1C, and the initial discharge specific capacity was 1 098 mAh·g-1 at 0.2C, the discharge specific capacity can remain 879 mAh·g-1 even after 200 cycles, and the average decay rate of each cycle was 0.09%, showing good cycle performance.
Using carbon cloth (CC) as a flexible substrate, needle-like network structure NiCo2O4 was grown on the surface of CC by hydrothermal method, and then NiCo2O4@CC composites were prepared and used for lithium-sulfur battery. NiCo2O4 grows vertically on the surface of carbon fiber to form a three-dimensional network of nano-needle clusters, which provides more space for sulfur storage and effectively alleviates the volume expansion of sulfur electrode. Through adsorption experiments, it is proved that NiCo2O4@CC can effectively adsorb polysulfide, thus inhibiting the shuttle effect of polysulfide. Compared with CC/S (933 mAh·g-1), NiCo2O4@CC/S composite had better battery performance. The initial discharge specific capacity was as high as 1 467 mAh·g-1 at 0.1C, and the initial discharge specific capacity was 1 098 mAh·g-1 at 0.2C, the discharge specific capacity can remain 879 mAh·g-1 even after 200 cycles, and the average decay rate of each cycle was 0.09%, showing good cycle performance.
2021, 37(11): 1950-1960
doi: 10.11862/CJIC.2021.218
Abstract:
A Dabco-cobalt cyanide hydrogen-bonding framework crystal material, (H3O)(H2Dabco)[Co(CN)6]·H2O (1), has been synthesized by solvent evaporation in the mixed solution of methanol and water with 1, 4-diazabicyclo[2.2.2]octane (Dabco) and cobalt cyanide. The structure, thermal energy and electrical properties of the crystal were characterized by single crystal X-ray diffraction, infrared spectroscopy, elemental analysis, X-ray powder diffraction, thermogravimetric analysis, differential scanning calorimetry and variable temperature-frequency dielectric constant test. The space group of the crystal is P21/c, which belongs to the monoclinic system at low and room temperature. The structure shows that the cobalt cyano anion, water molecules and protonated water molecules are mutually connected through hydrogen bonds in the crystal to form a three-dimensional network framework, and the protonated (H2Dabco)2+ cations are embedded in it forming a molecular motor-type cystic structure. With the increase of temperature, the (H2Dabco)2+ cations are twisted, which causes a phase transition in the crystal structure near 254 K. Dielectric anomalies occurs along the three axes of the crystal, showing obvious dielectric anisotropy at the same temperature.
A Dabco-cobalt cyanide hydrogen-bonding framework crystal material, (H3O)(H2Dabco)[Co(CN)6]·H2O (1), has been synthesized by solvent evaporation in the mixed solution of methanol and water with 1, 4-diazabicyclo[2.2.2]octane (Dabco) and cobalt cyanide. The structure, thermal energy and electrical properties of the crystal were characterized by single crystal X-ray diffraction, infrared spectroscopy, elemental analysis, X-ray powder diffraction, thermogravimetric analysis, differential scanning calorimetry and variable temperature-frequency dielectric constant test. The space group of the crystal is P21/c, which belongs to the monoclinic system at low and room temperature. The structure shows that the cobalt cyano anion, water molecules and protonated water molecules are mutually connected through hydrogen bonds in the crystal to form a three-dimensional network framework, and the protonated (H2Dabco)2+ cations are embedded in it forming a molecular motor-type cystic structure. With the increase of temperature, the (H2Dabco)2+ cations are twisted, which causes a phase transition in the crystal structure near 254 K. Dielectric anomalies occurs along the three axes of the crystal, showing obvious dielectric anisotropy at the same temperature.
2021, 37(11): 1961-1969
doi: 10.11862/CJIC.2021.225
Abstract:
Aminopropyltriethoxysilane and oxalyl chloride were used as raw materials to synthesize silsesquioxanes containing imino and carbonyl functional groups. A composite with silver nanoparticles (average particle size of about 15 nm) uniformly dispersed on the surface of the siloxane polymer was obtained through coordination adsorption and reduction. The research results showed that the weight percentage of silver loaded in the composite was about 13.66% and p-nitrophenol (4-NP) was completely reduced to 4-aminophenol (4-AP) within 6 min at 25℃ in aqueous solution by the composite catalyst, and the composite catalyst remained 95% activity after used 7 times. Under room temperature and one atmospheric pressure, the highest activity of the composite catalyst was about 33.0 g4-AP·gAg-1, which showed excellent catalytic reduction performance.
Aminopropyltriethoxysilane and oxalyl chloride were used as raw materials to synthesize silsesquioxanes containing imino and carbonyl functional groups. A composite with silver nanoparticles (average particle size of about 15 nm) uniformly dispersed on the surface of the siloxane polymer was obtained through coordination adsorption and reduction. The research results showed that the weight percentage of silver loaded in the composite was about 13.66% and p-nitrophenol (4-NP) was completely reduced to 4-aminophenol (4-AP) within 6 min at 25℃ in aqueous solution by the composite catalyst, and the composite catalyst remained 95% activity after used 7 times. Under room temperature and one atmospheric pressure, the highest activity of the composite catalyst was about 33.0 g4-AP·gAg-1, which showed excellent catalytic reduction performance.
2021, 37(11): 1970-1980
doi: 10.11862/CJIC.2021.223
Abstract:
The nano-porous Ni-Co alloy was prepared by rapid solidification and dealloying. After vapor deposition of sulfur and hot hydrogen reduction, nano-porous Co9S8/Ni3S2 composite electrode materials with surface mesoporous were prepared. The results showed that sulfur atoms and Ni-Co alloys formed CoS2/NiS2 composite phases in situ, and after thermal hydrogen reduction, Co9S8/Ni3S2 composite phase with a low sulfur atom ratio was formed. This thermal hydrogen reduction process not only increases the electron density around the Co9S8/Ni3S2 elements, but also modulates heterogeneous interface with mesoporous structure, which improves the electron transport capacity and increases the active surface area. Compared with other Ni and Co sulfides that were prepared under the same condition, Co9S8/Ni3S2 had better hydrogen evolution reaction (HER) activity. When current density was 50 mA·cm-2, the hydrogen evolution overpotential of Co9S8/Ni3S2 was 234 mV, and Tafel slope was 106 mV·dec-1. After stabilization test, the voltage changed only 14 mV.
The nano-porous Ni-Co alloy was prepared by rapid solidification and dealloying. After vapor deposition of sulfur and hot hydrogen reduction, nano-porous Co9S8/Ni3S2 composite electrode materials with surface mesoporous were prepared. The results showed that sulfur atoms and Ni-Co alloys formed CoS2/NiS2 composite phases in situ, and after thermal hydrogen reduction, Co9S8/Ni3S2 composite phase with a low sulfur atom ratio was formed. This thermal hydrogen reduction process not only increases the electron density around the Co9S8/Ni3S2 elements, but also modulates heterogeneous interface with mesoporous structure, which improves the electron transport capacity and increases the active surface area. Compared with other Ni and Co sulfides that were prepared under the same condition, Co9S8/Ni3S2 had better hydrogen evolution reaction (HER) activity. When current density was 50 mA·cm-2, the hydrogen evolution overpotential of Co9S8/Ni3S2 was 234 mV, and Tafel slope was 106 mV·dec-1. After stabilization test, the voltage changed only 14 mV.
2021, 37(11): 1981-1990
doi: 10.11862/CJIC.2021.243
Abstract:
Ferroferric oxide/L-cysteine (Fe3O4/Cys) magnetic nanospheres were synthesized by one pot method. Subsequently, the obtained Fe3O4/Cys were further modified by conjugating iminodiacetic acid (IDA) to obtain Fe3O4/Cys/IDA nanospheres. It was indicated that L-Cys was grafted on the surface of Fe3O4 by -SH group and Fe3O4/Cys/IDA, with more branched chains and more -COOH groups, was obtained by amido bond formed by the -NH2 group of Fe3O4/Cys and the -COOH group of IDA. Due to the alternative short and long chains grafting, Fe3O4/Cys/IDA nanospheres displayed high density modification of -COOH groups. Meanwhile, we found that the adsorption of Pb2+, Cd2+, Cu2+, Co2+, Ni2+, Zn2+ ions by Fe3O4/Cys/IDA nanospheres were specific adsorption and that of Hg2+ ions was unspecific adsorption. And all the complexes (Fe3O4/Cys/IDA-M, M was the metal) obtained after immobilization exhibited good stability. Experimental equilibrium data were also analyzed by the Langmuir and Freundlich models, and the best fit was obtained with the Langmuir isotherm equation, which was monolayer homogeneous adsorption. The kinetic study indicated that the adsorption kinetic data was well described by the pseudo-second kinetic model and the maximum immobilization capacity was 49.05 mg·g-1, which was a fast and efficient heavy metal immoblization material.
Ferroferric oxide/L-cysteine (Fe3O4/Cys) magnetic nanospheres were synthesized by one pot method. Subsequently, the obtained Fe3O4/Cys were further modified by conjugating iminodiacetic acid (IDA) to obtain Fe3O4/Cys/IDA nanospheres. It was indicated that L-Cys was grafted on the surface of Fe3O4 by -SH group and Fe3O4/Cys/IDA, with more branched chains and more -COOH groups, was obtained by amido bond formed by the -NH2 group of Fe3O4/Cys and the -COOH group of IDA. Due to the alternative short and long chains grafting, Fe3O4/Cys/IDA nanospheres displayed high density modification of -COOH groups. Meanwhile, we found that the adsorption of Pb2+, Cd2+, Cu2+, Co2+, Ni2+, Zn2+ ions by Fe3O4/Cys/IDA nanospheres were specific adsorption and that of Hg2+ ions was unspecific adsorption. And all the complexes (Fe3O4/Cys/IDA-M, M was the metal) obtained after immobilization exhibited good stability. Experimental equilibrium data were also analyzed by the Langmuir and Freundlich models, and the best fit was obtained with the Langmuir isotherm equation, which was monolayer homogeneous adsorption. The kinetic study indicated that the adsorption kinetic data was well described by the pseudo-second kinetic model and the maximum immobilization capacity was 49.05 mg·g-1, which was a fast and efficient heavy metal immoblization material.
2021, 37(11): 1991-2001
doi: 10.11862/CJIC.2021.238
Abstract:
A nanoplatform Pt-Cu@PLL@HA based on PtCu nano-alloys encapsulated in the positively charged polylysine (PLL) and negatively charged hyaluronic acid (HA) was constructed via layer-by-layer (LBL) self-assem-bly technology. HA not only prolonged the blood circulation time of Pt-Cu@PLL@HA, but also realized the active tumor targeting and enhanced its high accumulation in tumor region. After fast HA degradation in response to hyaluronidase (HAase) in the tumor microenvironment, the site-specific exposure of Pt-Cu@PLL(+) was conducive to the uptake of tumor cells. Owing to the strong NIR-Ⅱ (the second near-infrared window) absorption capability of Pt-Cu alloy, the effective photothermal tumor ablation could be realized by the precise guidance of NIR-Ⅱ photoacoustic imaging.
A nanoplatform Pt-Cu@PLL@HA based on PtCu nano-alloys encapsulated in the positively charged polylysine (PLL) and negatively charged hyaluronic acid (HA) was constructed via layer-by-layer (LBL) self-assem-bly technology. HA not only prolonged the blood circulation time of Pt-Cu@PLL@HA, but also realized the active tumor targeting and enhanced its high accumulation in tumor region. After fast HA degradation in response to hyaluronidase (HAase) in the tumor microenvironment, the site-specific exposure of Pt-Cu@PLL(+) was conducive to the uptake of tumor cells. Owing to the strong NIR-Ⅱ (the second near-infrared window) absorption capability of Pt-Cu alloy, the effective photothermal tumor ablation could be realized by the precise guidance of NIR-Ⅱ photoacoustic imaging.
2021, 37(11): 2002-2010
doi: 10.11862/CJIC.2021.239
Abstract:
Nickel bicarbonate nanoparticles were grown in situ on carbon paper by one-step hydrothermal method. Powder X-ray diffraction and scanning electron microscopy were used to characterize the structure and morphology of the material. It was found that when pure phase Ni(HCO3)2 was loaded on carbon paper, it could provide more catalytically active sites which is beneficial to electron transport and catalytic reaction. Cyclic voltammetry and timecurrent response curves showed that the detection limit of the electrode was 0.98 μmol·L-1, the linear range was 2.95-1.02 mmol·L-1, and the sensitivity was 935 μA·L·mmol-1·cm-2. At the same time, it also exhibited excellent specificity and stability. In addition, the sensor can realize the rapid detection of glucose in dairy products. These results show that the synergistic effect of transition metal and conductive substrate can enhance the overall conductivity and catalytic performance of the composite material.
Nickel bicarbonate nanoparticles were grown in situ on carbon paper by one-step hydrothermal method. Powder X-ray diffraction and scanning electron microscopy were used to characterize the structure and morphology of the material. It was found that when pure phase Ni(HCO3)2 was loaded on carbon paper, it could provide more catalytically active sites which is beneficial to electron transport and catalytic reaction. Cyclic voltammetry and timecurrent response curves showed that the detection limit of the electrode was 0.98 μmol·L-1, the linear range was 2.95-1.02 mmol·L-1, and the sensitivity was 935 μA·L·mmol-1·cm-2. At the same time, it also exhibited excellent specificity and stability. In addition, the sensor can realize the rapid detection of glucose in dairy products. These results show that the synergistic effect of transition metal and conductive substrate can enhance the overall conductivity and catalytic performance of the composite material.
2021, 37(11): 2011-2019
doi: 10.11862/CJIC.2021.233
Abstract:
A fast and mild method was developed to prepare Co-MOF-74 nanoparticles with high crystallinity and uniform morphology at room temperature for efficient oxygen evolution reaction (OER) in alkaline media. Compared with the conventional hydrothermal route, the time required for synthesis was greatly reduced after introducing triethylamine: Co-MOF-74 nanoparticles (about 20 nm) could be readily available by stirring at room temperature for only 2 h. The nano-electrocatalyst exhibited a larger specific surface area (760 m2·g-1), excellent activities and stability for OER with an overpotential of 275 mV to achieve a current density of 10 mA·cm-2.
A fast and mild method was developed to prepare Co-MOF-74 nanoparticles with high crystallinity and uniform morphology at room temperature for efficient oxygen evolution reaction (OER) in alkaline media. Compared with the conventional hydrothermal route, the time required for synthesis was greatly reduced after introducing triethylamine: Co-MOF-74 nanoparticles (about 20 nm) could be readily available by stirring at room temperature for only 2 h. The nano-electrocatalyst exhibited a larger specific surface area (760 m2·g-1), excellent activities and stability for OER with an overpotential of 275 mV to achieve a current density of 10 mA·cm-2.
2021, 37(11): 2020-2028
doi: 10.11862/CJIC.2021.235
Abstract:
Here, SnS2 nanosheets with the size of 50-100 nm were synthesized by hydrothermal method, and was used as the resistive layer material (Cu/PMMA/SnS2/Ag, PMMA=polymethyl methacrylate) for the first time. The results showed that the ON/OFF ratio of Cu/PMMA/SnS2/Ag resistive random access memory was about 105, and the endurance was 2.7×103. The on-state voltage and off-state voltage were only about 0.28 and -0.19 V, respectively.
Here, SnS2 nanosheets with the size of 50-100 nm were synthesized by hydrothermal method, and was used as the resistive layer material (Cu/PMMA/SnS2/Ag, PMMA=polymethyl methacrylate) for the first time. The results showed that the ON/OFF ratio of Cu/PMMA/SnS2/Ag resistive random access memory was about 105, and the endurance was 2.7×103. The on-state voltage and off-state voltage were only about 0.28 and -0.19 V, respectively.
2021, 37(11): 2029-2036
doi: 10.11862/CJIC.2021.226
Abstract:
The photocatalytic activity of carbon nitride is greatly limited by the low visible-light utilization and fast photocarries recombination. Here, a new cobalt and carbon co-doped carbon nitride (CNCoC) was prepared via a one -step thermal condensation method using vitamin B12 (VB12) as the cobalt and carbon source mixed with urea. The characterization results indicate that the cobalt and carbon co-doping does not change the morphology, skeleton structure or functional groups of carbon nitride. However, the co-doping contributes to the enhanced surface area, optimized band structure and increased visible-light absorption. More importantly, compared to carbon doping, the synergistic effect of cobalt and carbon co-doping leads to more efficient photocarrier separation and transport. As a result, the photocatalytic hydrogen evolution rate of CNCoC-6 prepared with 6 mg VB12 reached 56.1 μmol·h-1 under visible light irradiation, which was 3.05 times that of pure carbon nitride (CN). While the carbon doped carbon nitride (CNC-6) only exhibited a hydrogen evolution rate to be 2.55 times that of CN.
The photocatalytic activity of carbon nitride is greatly limited by the low visible-light utilization and fast photocarries recombination. Here, a new cobalt and carbon co-doped carbon nitride (CNCoC) was prepared via a one -step thermal condensation method using vitamin B12 (VB12) as the cobalt and carbon source mixed with urea. The characterization results indicate that the cobalt and carbon co-doping does not change the morphology, skeleton structure or functional groups of carbon nitride. However, the co-doping contributes to the enhanced surface area, optimized band structure and increased visible-light absorption. More importantly, compared to carbon doping, the synergistic effect of cobalt and carbon co-doping leads to more efficient photocarrier separation and transport. As a result, the photocatalytic hydrogen evolution rate of CNCoC-6 prepared with 6 mg VB12 reached 56.1 μmol·h-1 under visible light irradiation, which was 3.05 times that of pure carbon nitride (CN). While the carbon doped carbon nitride (CNC-6) only exhibited a hydrogen evolution rate to be 2.55 times that of CN.
2021, 37(11): 2037-2046
doi: 10.11862/CJIC.2021.236
Abstract:
This study mainly focused on the effect of substituting-CH2-CH2-with-SiMe2-SiMe2-or-CH2-SiMe2-on the coordination ability of 15-crown-5 with Li+ based on density functional theory calculations. The results show that Si doping can not only lead to increased size of crown ethers, but can also effectively regulate the coordination ability of crown ethers with Li+ by tuning the doping level and position. Atoms in molecules (AIM) analysis of electron density and symmetry-adapted perturbation theory (SAPT) energy decomposition analysis indicate that the interactions between the intrinsic/Si-doped crown ethers and Li+ are essentially ion-dipole interactions, accompanied by slight orbital polarization and electron transfer. Since the electrons of Si are polarized more easily by O and Li+ than those of carbon atoms, Si doping can thus enhance the electrostatic and induction interactions between crown ethers and Li+. However, natural population analysis demonstrates that if the Si doping introduces Si-O-Si structures into the crown ethers, it could prevent O from fully polarizing the electrons of Si, and results in a closer distance between positively charged Si and Li+, thereby impeding the coordination of crown ethers with Li+.
This study mainly focused on the effect of substituting-CH2-CH2-with-SiMe2-SiMe2-or-CH2-SiMe2-on the coordination ability of 15-crown-5 with Li+ based on density functional theory calculations. The results show that Si doping can not only lead to increased size of crown ethers, but can also effectively regulate the coordination ability of crown ethers with Li+ by tuning the doping level and position. Atoms in molecules (AIM) analysis of electron density and symmetry-adapted perturbation theory (SAPT) energy decomposition analysis indicate that the interactions between the intrinsic/Si-doped crown ethers and Li+ are essentially ion-dipole interactions, accompanied by slight orbital polarization and electron transfer. Since the electrons of Si are polarized more easily by O and Li+ than those of carbon atoms, Si doping can thus enhance the electrostatic and induction interactions between crown ethers and Li+. However, natural population analysis demonstrates that if the Si doping introduces Si-O-Si structures into the crown ethers, it could prevent O from fully polarizing the electrons of Si, and results in a closer distance between positively charged Si and Li+, thereby impeding the coordination of crown ethers with Li+.
