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2020 Volume 36 Issue 5
2020, 36(5): 777-794
doi: 10.11862/CJIC.2020.108
Abstract:
Inorganic nanomaterials are gradually playing important roles in a myriad of fields such as energy and biomedicine. Therefore, the development of various protocols for the synthesis of inorganic nanomaterials has attracted widespread attention in the last decades. Biomineralization common in nature endows living organisms the ability to synthesize various inorganic nanomaterials with marvellous structures and diverse features. Inorganic nanomaterials synthesized by microbes are eco-friendly, low-cost, and biocompatible, thus becoming an important issue in nanomaterial science. In this review, we provide a brief overview of the recent research efforts on the microbial biosynthesis of inorganic nanomaterials and their mechanisms, affecting factors as well as potential applications. In addition, the current challenges and future perspective of microbial biosynthesis of inorganic nanomaterials have also been discussed.
Inorganic nanomaterials are gradually playing important roles in a myriad of fields such as energy and biomedicine. Therefore, the development of various protocols for the synthesis of inorganic nanomaterials has attracted widespread attention in the last decades. Biomineralization common in nature endows living organisms the ability to synthesize various inorganic nanomaterials with marvellous structures and diverse features. Inorganic nanomaterials synthesized by microbes are eco-friendly, low-cost, and biocompatible, thus becoming an important issue in nanomaterial science. In this review, we provide a brief overview of the recent research efforts on the microbial biosynthesis of inorganic nanomaterials and their mechanisms, affecting factors as well as potential applications. In addition, the current challenges and future perspective of microbial biosynthesis of inorganic nanomaterials have also been discussed.
2020, 36(5): 795-801
doi: 10.11862/CJIC.2020.113
Abstract:
In this work, Na-rich, low-defect Fe-based Prussian blue material has been synthesized by coprecipitation method at room temperature using antioxidant (ascorbic acid) and chelating agent (sodium citrate). At 0.1C, the material exhibited a high capacity of 110.0 mAh·g-1 due to high Na content and low crystal defect. The material also showed excellent rate capability and cycling stability due to the border-rich structure and low defect, besides unique open framework structure of the Prussian blue material. At a current rate up to 10C, the material can still yield a capacity of 86.6 mAh·g-1. After 1 300 cycles at current density of 1C, the material could keep a capacity of 90.1 mAh·g-1, corresponding to the capacity retention of 86.9%.
In this work, Na-rich, low-defect Fe-based Prussian blue material has been synthesized by coprecipitation method at room temperature using antioxidant (ascorbic acid) and chelating agent (sodium citrate). At 0.1C, the material exhibited a high capacity of 110.0 mAh·g-1 due to high Na content and low crystal defect. The material also showed excellent rate capability and cycling stability due to the border-rich structure and low defect, besides unique open framework structure of the Prussian blue material. At a current rate up to 10C, the material can still yield a capacity of 86.6 mAh·g-1. After 1 300 cycles at current density of 1C, the material could keep a capacity of 90.1 mAh·g-1, corresponding to the capacity retention of 86.9%.
2020, 36(5): 802-810
doi: 10.11862/CJIC.2020.073
Abstract:
Urea was used as the nitrogen source precursor, nitrogen-doped reduced graphene oxide was prepared by thermal annealing, and then nitrogen-doped reduced graphene oxide/tri-cobalt-doped hybrid nanosheet was prepared by hydrothermal method using cobalt acetylacetonate as cobalt source. Reduction and oxygen evolution of the bifunctional catalyst. Firstly, the microstructures were characterized by scanning electron microscope (SEM), transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS). The catalysts were found to have a unique layered mesoporous structure. The formation of spinel tetraoxide with spinel structure in the catalyst was verified by X-ray electron spectrometer (XPS) and X-ray diffractometer (XRD). Thermogravimetric analysis indicated that the content of nitrogen-doped graphene and tricobalt tetroxide in the catalyst was 68.43% and 31.57%(w/w), respectively. Electrochemical tests such as rotating disk electrodes showed that the catalyst exhibited superior oxygen reduction and oxygen evolution catalytic properties. In an alkaline environment, the initial potential, half-wave potential, and limiting current density were 1.171 V, 0.718 V, and 4.3 mA·cm-2, respectively. The Koutecky-Levich equation shows that the catalyst directly reduces oxygen by a four-electron process. In water, the catalytic efficiency was high. The oxygen evolution catalytic performance test showed that the overpotential at the current density of 10 mA·cm-2 was 1.789 V, and the Tafel slope was 134 mV·dec-1, which had good oxygen evolution kinetics. The difference of overpotential (ΔE) was 1.071 V, which was superior to common dual-function catalysts.
Urea was used as the nitrogen source precursor, nitrogen-doped reduced graphene oxide was prepared by thermal annealing, and then nitrogen-doped reduced graphene oxide/tri-cobalt-doped hybrid nanosheet was prepared by hydrothermal method using cobalt acetylacetonate as cobalt source. Reduction and oxygen evolution of the bifunctional catalyst. Firstly, the microstructures were characterized by scanning electron microscope (SEM), transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS). The catalysts were found to have a unique layered mesoporous structure. The formation of spinel tetraoxide with spinel structure in the catalyst was verified by X-ray electron spectrometer (XPS) and X-ray diffractometer (XRD). Thermogravimetric analysis indicated that the content of nitrogen-doped graphene and tricobalt tetroxide in the catalyst was 68.43% and 31.57%(w/w), respectively. Electrochemical tests such as rotating disk electrodes showed that the catalyst exhibited superior oxygen reduction and oxygen evolution catalytic properties. In an alkaline environment, the initial potential, half-wave potential, and limiting current density were 1.171 V, 0.718 V, and 4.3 mA·cm-2, respectively. The Koutecky-Levich equation shows that the catalyst directly reduces oxygen by a four-electron process. In water, the catalytic efficiency was high. The oxygen evolution catalytic performance test showed that the overpotential at the current density of 10 mA·cm-2 was 1.789 V, and the Tafel slope was 134 mV·dec-1, which had good oxygen evolution kinetics. The difference of overpotential (ΔE) was 1.071 V, which was superior to common dual-function catalysts.
2020, 36(5): 811-818
doi: 10.11862/CJIC.2020.090
Abstract:
Two-dimensional (2D) quaternary selenides containing cadmium mercury, K8Cd2.79Hg9.21Se16 (1) and Rb4Hg3.04Cd2.96Se8 (2), were synthesized utilizing solvothermal method. Single crystal X-ray analyses reveal that compound 1 crystallizes in the orthorhombic space group Pbcn, with a=1.082 71(17) nm, b=0.678 73(10) nm, c=1.415 0(2) nm, Z=1; compound 2 crystallizes in the orthorhombic space group Ibam, with a=0.640 72(10) nm, b=1.160 25(16) nm, c=1.452 0(2) nm, Z=2. Compound 1 contains anion layer (Cd2.79Hg9.21Se16)n8n- of eight-membered ring Cd2Hg2Se4 and six-membered ring CdHg2Se3. Compound 2 contains anion layer (Hg3.04Cd2.96Se8)n4n- of eight-membered ring Cd2(Cd/Hg)2Se4, four-membered ring CdHgSe2 and (Cd/Hg)2Se2. These two compounds were structurally characterized by scanning electron micrograph and energy-dispersive X-ray spectroscopy analysis, powder X-ray diffraction measurement, thermal analysis, solid-state optical diffuse reflectance and fluorescence properties.
Two-dimensional (2D) quaternary selenides containing cadmium mercury, K8Cd2.79Hg9.21Se16 (1) and Rb4Hg3.04Cd2.96Se8 (2), were synthesized utilizing solvothermal method. Single crystal X-ray analyses reveal that compound 1 crystallizes in the orthorhombic space group Pbcn, with a=1.082 71(17) nm, b=0.678 73(10) nm, c=1.415 0(2) nm, Z=1; compound 2 crystallizes in the orthorhombic space group Ibam, with a=0.640 72(10) nm, b=1.160 25(16) nm, c=1.452 0(2) nm, Z=2. Compound 1 contains anion layer (Cd2.79Hg9.21Se16)n8n- of eight-membered ring Cd2Hg2Se4 and six-membered ring CdHg2Se3. Compound 2 contains anion layer (Hg3.04Cd2.96Se8)n4n- of eight-membered ring Cd2(Cd/Hg)2Se4, four-membered ring CdHgSe2 and (Cd/Hg)2Se2. These two compounds were structurally characterized by scanning electron micrograph and energy-dispersive X-ray spectroscopy analysis, powder X-ray diffraction measurement, thermal analysis, solid-state optical diffuse reflectance and fluorescence properties.
2020, 36(5): 819-826
doi: 10.11862/CJIC.2020.101
Abstract:
Eleven diorganotins containing silicon of salicylaldehyde thiosemicarbazone were synthesized and characterized through 1H NMR, 13C NMR, IR spectra, elemental analysis and X-ray single crystal diffraction tests. The result shows that the thiosemicarbazone Schiff base coordinates with tin atom as tridentate dianionic ligand through thephenolic oxygen, imine nitrogen and mercaptan sulfur, forming a parallel five and six-member heterocyclic structures. The preliminary bioassay result shows that these compounds have a good antitumor activity in vitro against MDA-MB-231 and MCF-7.
Eleven diorganotins containing silicon of salicylaldehyde thiosemicarbazone were synthesized and characterized through 1H NMR, 13C NMR, IR spectra, elemental analysis and X-ray single crystal diffraction tests. The result shows that the thiosemicarbazone Schiff base coordinates with tin atom as tridentate dianionic ligand through thephenolic oxygen, imine nitrogen and mercaptan sulfur, forming a parallel five and six-member heterocyclic structures. The preliminary bioassay result shows that these compounds have a good antitumor activity in vitro against MDA-MB-231 and MCF-7.
2020, 36(5): 827-834
doi: 10.11862/CJIC.2020.098
Abstract:
Hollow microsphere Bi2MoO6 photocatalyst was prepared by alcohol synthesis and high temperature annealing using sodium molybdate and lanthanum nitrate pentahydrate as raw materials. The microstructure, specific surface area and optical characteristics of as-prepared Bi2MoO6 were characterized by X-ray diffraction (XRD), infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), physical adsorption analyzer, ultraviolet-visible diffuse reflectance (UV-Vis DRS), fluorescence spectroscopy (PL) and electrochemical test. The photocatalytic performance of Bi2MoO6 on the aqueous solution of ofloxacin (OFX) was investigated under the visible light. The results show that average diameter (500 nm) of the hollow Bi2MoO6 was synthesized with as more 5 times of the specific surface area as the sheet Bi2MoO6. The hollow Bi2MoO6 provides a large number of adsorption sites for reactants. The degradation rate of OFX (pH=7, 10 mg·L-1) by 1 g·L-1 hollow Bi2MoO6 reach 64% under 120 min visible light irradiation, while the sheet Bi2MoO6 under the same conditions was only 31%. The hollow spherical Bi2MoO6 showed the excellent photocatalytic capacity in strong alkaline environment, and the degradation rate of OFXreached 79%, which has a high utilization value in alkaline environment.
Hollow microsphere Bi2MoO6 photocatalyst was prepared by alcohol synthesis and high temperature annealing using sodium molybdate and lanthanum nitrate pentahydrate as raw materials. The microstructure, specific surface area and optical characteristics of as-prepared Bi2MoO6 were characterized by X-ray diffraction (XRD), infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), physical adsorption analyzer, ultraviolet-visible diffuse reflectance (UV-Vis DRS), fluorescence spectroscopy (PL) and electrochemical test. The photocatalytic performance of Bi2MoO6 on the aqueous solution of ofloxacin (OFX) was investigated under the visible light. The results show that average diameter (500 nm) of the hollow Bi2MoO6 was synthesized with as more 5 times of the specific surface area as the sheet Bi2MoO6. The hollow Bi2MoO6 provides a large number of adsorption sites for reactants. The degradation rate of OFX (pH=7, 10 mg·L-1) by 1 g·L-1 hollow Bi2MoO6 reach 64% under 120 min visible light irradiation, while the sheet Bi2MoO6 under the same conditions was only 31%. The hollow spherical Bi2MoO6 showed the excellent photocatalytic capacity in strong alkaline environment, and the degradation rate of OFXreached 79%, which has a high utilization value in alkaline environment.
2020, 36(5): 835-840
doi: 10.11862/CJIC.2020.095
Abstract:
g-C3N4 with hierarchical porous structure was synthesized through a simple one-step calcination method by using monodisperse silica as a template. In comparison with the bulk g-C3N4, the hierarchical porous structure of g-C3N4 not only improved the visible light absorption performance and specific surface area, but also facilitated the separation of photogenerated electron-holes. Moreover, g-C3N4 with hierarchical pore structure has significantly enhanced visible light-driven photocatalytic hydrogen production activity. When the mass ratio of SiO2 and dicyandiamine was 1:1, the obtained g-C3N4 (C3N4-2) exhibited obviously enhanced visible-light-driven photocatalytic activity for H2 evolution, and its hydrogen production rate was nearly 18 times that of bulk g-C3N4.
g-C3N4 with hierarchical porous structure was synthesized through a simple one-step calcination method by using monodisperse silica as a template. In comparison with the bulk g-C3N4, the hierarchical porous structure of g-C3N4 not only improved the visible light absorption performance and specific surface area, but also facilitated the separation of photogenerated electron-holes. Moreover, g-C3N4 with hierarchical pore structure has significantly enhanced visible light-driven photocatalytic hydrogen production activity. When the mass ratio of SiO2 and dicyandiamine was 1:1, the obtained g-C3N4 (C3N4-2) exhibited obviously enhanced visible-light-driven photocatalytic activity for H2 evolution, and its hydrogen production rate was nearly 18 times that of bulk g-C3N4.
2020, 36(5): 841-849
doi: 10.11862/CJIC.2020.096
Abstract:
The effects of AZO coating on its structure, morphology and electrochemical properties of the MgMn2O4 were investigated by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), charge and discharge tests and so on. It is shown that Al-doped ZnO (AZO) coating can effectively improve both the electronic conductivity and Li+ diffusion, consequently improved its rate capability. Moreover, AZO coating can also remain the continuous conductive network of the electrode, therefore improve its cyclic stability. The reversible capacity of 5%(w/w) AZO-coated MgMn2O4 was 590.3 mAh·g-1 after 200 cycles, much higher than that of the bare MgMn2O4 (295.9 mAh·g-1) and the reported value in literatures.
The effects of AZO coating on its structure, morphology and electrochemical properties of the MgMn2O4 were investigated by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), charge and discharge tests and so on. It is shown that Al-doped ZnO (AZO) coating can effectively improve both the electronic conductivity and Li+ diffusion, consequently improved its rate capability. Moreover, AZO coating can also remain the continuous conductive network of the electrode, therefore improve its cyclic stability. The reversible capacity of 5%(w/w) AZO-coated MgMn2O4 was 590.3 mAh·g-1 after 200 cycles, much higher than that of the bare MgMn2O4 (295.9 mAh·g-1) and the reported value in literatures.
2020, 36(5): 850-856
doi: 10.11862/CJIC.2020.104
Abstract:
Using diethyl phthalate (DEP) as template, molecularly imprinted TiO2 nanoparticles were deposited on wall of TNA and DEP-molecularly-imprinted TNA (DM-TNA) was fabricated. X-ray diffraction (XRD) analysis demonstrated that crystal structure of DM-TNA was anatase. Scanning electron microscopy (SEM) measurements showed that TiO2 nanoparticles with a size about 20 nm were uniformly coated on the wall of TNA. The results of photoelectrocatalytic degradation of the mixed solution of DEP and 2, 4-dichlorophenol (DCP) showed that the degradation activity of DEP on the DM-TNA was higher than that on non molecularly imprinted TNA (NM-TNA), while the degradation activity of DCP on the DM-TNA was lower than that on NM-TNA. The rate constant of DM-TNA for the degradation of DEP was 2.76 times that of NM-TNA.
Using diethyl phthalate (DEP) as template, molecularly imprinted TiO2 nanoparticles were deposited on wall of TNA and DEP-molecularly-imprinted TNA (DM-TNA) was fabricated. X-ray diffraction (XRD) analysis demonstrated that crystal structure of DM-TNA was anatase. Scanning electron microscopy (SEM) measurements showed that TiO2 nanoparticles with a size about 20 nm were uniformly coated on the wall of TNA. The results of photoelectrocatalytic degradation of the mixed solution of DEP and 2, 4-dichlorophenol (DCP) showed that the degradation activity of DEP on the DM-TNA was higher than that on non molecularly imprinted TNA (NM-TNA), while the degradation activity of DCP on the DM-TNA was lower than that on NM-TNA. The rate constant of DM-TNA for the degradation of DEP was 2.76 times that of NM-TNA.
Preparation and Performance of High Stability Cathode Material MnO2@MgO for Aqueous Zinc-Ion Battery
2020, 36(5): 857-863
doi: 10.11862/CJIC.2020.094
Abstract:
MnO2@MgO core-shell microspheres were synthesized by coprecipitation method and pyrolytic process. The materials were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscopy (TEM). It is found that MgO coating did not change the microstructure of MnO2, and the coating layer was composed of nanoparticles with a thickness of about 50 nm. As a result, electrochemical property showed that the discharge specific capacity of the coated material was obviously improved. The maximum discharge specific capacity was 274.3 mAh·g-1 at the current density of 100 mA·g-1, which was 12.8% higher than that of the uncoated material. Meanwhile, the coated material exhibited excellent cycle stability with 84.1% discharge specific capacity retention after 500 cycles at the current density of 1 000 mA·g-1. Obviously, the MgO coating layer prevents directly contact between MnO2 and electrolyte, and suppresses the dissolution of manganese during the charge and discharge process, thus significantly improves the cycle performance of MnO2.
MnO2@MgO core-shell microspheres were synthesized by coprecipitation method and pyrolytic process. The materials were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscopy (TEM). It is found that MgO coating did not change the microstructure of MnO2, and the coating layer was composed of nanoparticles with a thickness of about 50 nm. As a result, electrochemical property showed that the discharge specific capacity of the coated material was obviously improved. The maximum discharge specific capacity was 274.3 mAh·g-1 at the current density of 100 mA·g-1, which was 12.8% higher than that of the uncoated material. Meanwhile, the coated material exhibited excellent cycle stability with 84.1% discharge specific capacity retention after 500 cycles at the current density of 1 000 mA·g-1. Obviously, the MgO coating layer prevents directly contact between MnO2 and electrolyte, and suppresses the dissolution of manganese during the charge and discharge process, thus significantly improves the cycle performance of MnO2.
2020, 36(5): 864-874
doi: 10.11862/CJIC.2020.074
Abstract:
The CdS@g-C3N4 core-shell composite nanoparticles were successfully prepared by a hydrothermal method with the addition of ethylenediamine and EDTA-2Na. The nucleation and growth mechanism of CdS@g-C3N4 was also discussed. The specific surface area of CdS@g-C3N4 core-shell composite nanoparticles was 14 times larger than that of the pure CdS nanoparticles. CdS@g-C3N4, which was prepared under the reaction conditions of 180℃, 4 h and 1.9:1 (the mass ratio of CdS to g-C3N4), exhibited the best catalytic performance. The degradation efficiency of RhB with CdS@g-C3N4 composite reached 95.2% after 2 h of irradiation under 300 W xenon, which was significantly higher than that over pure CdS. After three cycles, CdS@g-C3N4 showed no obvious changes in the morphology, structure and photocatalytic performance.
The CdS@g-C3N4 core-shell composite nanoparticles were successfully prepared by a hydrothermal method with the addition of ethylenediamine and EDTA-2Na. The nucleation and growth mechanism of CdS@g-C3N4 was also discussed. The specific surface area of CdS@g-C3N4 core-shell composite nanoparticles was 14 times larger than that of the pure CdS nanoparticles. CdS@g-C3N4, which was prepared under the reaction conditions of 180℃, 4 h and 1.9:1 (the mass ratio of CdS to g-C3N4), exhibited the best catalytic performance. The degradation efficiency of RhB with CdS@g-C3N4 composite reached 95.2% after 2 h of irradiation under 300 W xenon, which was significantly higher than that over pure CdS. After three cycles, CdS@g-C3N4 showed no obvious changes in the morphology, structure and photocatalytic performance.
2020, 36(5): 875-884
doi: 10.11862/CJIC.2020.105
Abstract:
Gold and copper nanoparticles were supported on the surface of zinc-aluminum layered double hydroxides (AuCu/ZnAl-LDHs) by method of impregnation-reduction. Mixed metal oxides (AuCu/ZnAl-LDO) were obtained from AuCu/ZnAl-LDHs after calcination. The as-prepared photocatalysts were well characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and UVVis diffuse reflectance spectroscopy (UV-Vis DRS) to investigate the crystal structures, microstructure, elemental composition and visible light absorption capability. The photocatalytic performance of AuCu/ZnAl-LDO was studied by degradation of catechol under visible Light. The results of experimental indicated that AuCu/ZnAl-LDO had stronger visible light absorption capacity than pure zinc-aluminum mixed metal oxides (ZnAl-LDO). The degradation efficiency of catechol reached 94.5% after 5 h irradiation, when loading ratio of AuCu was 5:1 and calcination temperature was 400℃. The photodegradation reaction rate constant was 13.4 times that of ZnAl-LDO. In addition, The path of AuCu/ZnAl-LDO electron transfer was deduced and a possible photocatalytic degradation mechanism was proposed by density functional theory calculation.
Gold and copper nanoparticles were supported on the surface of zinc-aluminum layered double hydroxides (AuCu/ZnAl-LDHs) by method of impregnation-reduction. Mixed metal oxides (AuCu/ZnAl-LDO) were obtained from AuCu/ZnAl-LDHs after calcination. The as-prepared photocatalysts were well characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and UVVis diffuse reflectance spectroscopy (UV-Vis DRS) to investigate the crystal structures, microstructure, elemental composition and visible light absorption capability. The photocatalytic performance of AuCu/ZnAl-LDO was studied by degradation of catechol under visible Light. The results of experimental indicated that AuCu/ZnAl-LDO had stronger visible light absorption capacity than pure zinc-aluminum mixed metal oxides (ZnAl-LDO). The degradation efficiency of catechol reached 94.5% after 5 h irradiation, when loading ratio of AuCu was 5:1 and calcination temperature was 400℃. The photodegradation reaction rate constant was 13.4 times that of ZnAl-LDO. In addition, The path of AuCu/ZnAl-LDO electron transfer was deduced and a possible photocatalytic degradation mechanism was proposed by density functional theory calculation.
2020, 36(5): 885-892
doi: 10.11862/CJIC.2020.093
Abstract:
The zeolite Na-[Fe]-ZSM-5 containing framework iron was successfully synthesized by hydrothermal synthesis, and the Pt/Na-[Fe]-ZSM-5 catalysts were prepared by ion exchange method. The catalytic performance of the catalysts for the dehydrogenation of long-chain alkanes to mono-olefin was investigated through the dehydrogenation of n-dodecane. The catalysts were characterized by N2 adsorption-desorption test, X-ray diffraction (XRD), Fourier transform infrared spectrum (FT-IR), NH3 temperature-programmed desorption (NH3-TPD), Ir spectra of pyridine adsorped (Py-IR), CO chemisorption and transmission electron microscope (TEM). The results show that the surface acidity of the catalyst can be adjusted by controlling the content of framework iron; the support, ZSM-5 containing framework iron, has the effect of inhibiting metal grain growth and maintaining high dispersion of metals; The Pt/Na-[Fe]-ZSM-5-50 catalyst had weak surface acid sites (0.69 mmol·g-1) and highly dispersed Pt sites, so it exhibited high activity and stability for the dehydrogenation and high selectivity of mono-olefin. When the conversion was stable at ~20%, the TOF was 4.56 s-1 and the selectivity of mono-olefin was 92.7%. In the experimental range, the amount of weak acid sites on the surface of Pt/Na-[Fe]-ZSM-5 catalyst and its intrinsic activity (TOF) of dehydrogenation increased with the increase of iron content.
The zeolite Na-[Fe]-ZSM-5 containing framework iron was successfully synthesized by hydrothermal synthesis, and the Pt/Na-[Fe]-ZSM-5 catalysts were prepared by ion exchange method. The catalytic performance of the catalysts for the dehydrogenation of long-chain alkanes to mono-olefin was investigated through the dehydrogenation of n-dodecane. The catalysts were characterized by N2 adsorption-desorption test, X-ray diffraction (XRD), Fourier transform infrared spectrum (FT-IR), NH3 temperature-programmed desorption (NH3-TPD), Ir spectra of pyridine adsorped (Py-IR), CO chemisorption and transmission electron microscope (TEM). The results show that the surface acidity of the catalyst can be adjusted by controlling the content of framework iron; the support, ZSM-5 containing framework iron, has the effect of inhibiting metal grain growth and maintaining high dispersion of metals; The Pt/Na-[Fe]-ZSM-5-50 catalyst had weak surface acid sites (0.69 mmol·g-1) and highly dispersed Pt sites, so it exhibited high activity and stability for the dehydrogenation and high selectivity of mono-olefin. When the conversion was stable at ~20%, the TOF was 4.56 s-1 and the selectivity of mono-olefin was 92.7%. In the experimental range, the amount of weak acid sites on the surface of Pt/Na-[Fe]-ZSM-5 catalyst and its intrinsic activity (TOF) of dehydrogenation increased with the increase of iron content.
2020, 36(5): 893-900
doi: 10.11862/CJIC.2020.092
Abstract:
In this paper, an ordered mesoporous Si/C composite structure was prepared successfully for the anode materials of Li-ion batteries through the synthesis of SiO2-ordered mesoporous precursor (SiO2-OMPs) by a P123-copolymer templet route and then a magnesiothermic reduction reaction (MRR) for the SiO2-OMPs precursor and ensuing a phenolic-resin based carbon-capsuling treatment. From the observations of SEM/TEM, it is found that the morphology of SiO2-OMPs can be got well-controlled by HCl concentration and obtained a short rod with densified geometrical stacking under high acid concentration, and the ordered mesoporous symmetry kept unchanged perfectly through later MRR and C-capsuling routes. In addition, the detailed and reasonable analyses based on XRD data reveal that MRR process consists of two-step serial reactions:the Mg2Si intermediate formation from Mg and SiO2 reactants and its transition to final Si products by re-reducing SiO2. The slow feature of the solid/solid diffusive reaction in the second step restrains the completion of whole reduction process, resulting in a low yield of silicon and the existence of some impurity phases. Electrochemical measurements show that the ordered mesoporous Si/C composite exhibited excellent cyclic stability and rate performance, which can be attributed to the robust architect and unblocked mesopore system within such composite structure.
In this paper, an ordered mesoporous Si/C composite structure was prepared successfully for the anode materials of Li-ion batteries through the synthesis of SiO2-ordered mesoporous precursor (SiO2-OMPs) by a P123-copolymer templet route and then a magnesiothermic reduction reaction (MRR) for the SiO2-OMPs precursor and ensuing a phenolic-resin based carbon-capsuling treatment. From the observations of SEM/TEM, it is found that the morphology of SiO2-OMPs can be got well-controlled by HCl concentration and obtained a short rod with densified geometrical stacking under high acid concentration, and the ordered mesoporous symmetry kept unchanged perfectly through later MRR and C-capsuling routes. In addition, the detailed and reasonable analyses based on XRD data reveal that MRR process consists of two-step serial reactions:the Mg2Si intermediate formation from Mg and SiO2 reactants and its transition to final Si products by re-reducing SiO2. The slow feature of the solid/solid diffusive reaction in the second step restrains the completion of whole reduction process, resulting in a low yield of silicon and the existence of some impurity phases. Electrochemical measurements show that the ordered mesoporous Si/C composite exhibited excellent cyclic stability and rate performance, which can be attributed to the robust architect and unblocked mesopore system within such composite structure.
2020, 36(5): 901-907
doi: 10.11862/CJIC.2020.112
Abstract:
A series of red emitting phosphors Sr3La2-xGe3O12:xSm3+ (0 ≤ x ≤ 0.04) were synthesized through a conventional high temperature solid state method, and the morphology, elemental composition, crystal structure, luminescence properties, and thermal stability were studied. The results showed that sample Sr3La1.97Ge3O12:0.03Sm3+ had a broad crystal size distribution. The energy dispersive spectrum (EDS) analysis predicted that there were only Sr, La, Ge, O, Sm elements in Sr3La1.97Ge3O12:0.03Sm3+. The Rietveld refinement patterns of Sr3La1.97Ge3O12:0.03Sm3+ crystallized in a hexagonal unit cell fitted well with the observed XRD results. The host lattice Sr3La2Ge3O12 exhibited an energy band gap of 5.54 eV which belongs to the class of wide band gap materials. Moreover, samples Sr3La2-xGe3O12:xSm3+ (0 ≤ x ≤ 0.04) exhibited a maximum emission peak located at 601 nm ascribed to the 6H5/2→4L13/2 energy level transitions of Sm3+ when excited at 404 nm. Significantly, sample Sr3La1.97Ge3O12:0.03Sm3+ not only possessed a relatively optimum photoluminescence properties with a Commission Internationale De I'eclairage (CIE) coordinates of (0.532 1, 0.460 1) and a color purity up to 94.2% among these synthesized materials, but also exhibited splendid thermal stability with the photoluminescence intensity remained 81.6% of its initial value when the temperature was 423 K.
A series of red emitting phosphors Sr3La2-xGe3O12:xSm3+ (0 ≤ x ≤ 0.04) were synthesized through a conventional high temperature solid state method, and the morphology, elemental composition, crystal structure, luminescence properties, and thermal stability were studied. The results showed that sample Sr3La1.97Ge3O12:0.03Sm3+ had a broad crystal size distribution. The energy dispersive spectrum (EDS) analysis predicted that there were only Sr, La, Ge, O, Sm elements in Sr3La1.97Ge3O12:0.03Sm3+. The Rietveld refinement patterns of Sr3La1.97Ge3O12:0.03Sm3+ crystallized in a hexagonal unit cell fitted well with the observed XRD results. The host lattice Sr3La2Ge3O12 exhibited an energy band gap of 5.54 eV which belongs to the class of wide band gap materials. Moreover, samples Sr3La2-xGe3O12:xSm3+ (0 ≤ x ≤ 0.04) exhibited a maximum emission peak located at 601 nm ascribed to the 6H5/2→4L13/2 energy level transitions of Sm3+ when excited at 404 nm. Significantly, sample Sr3La1.97Ge3O12:0.03Sm3+ not only possessed a relatively optimum photoluminescence properties with a Commission Internationale De I'eclairage (CIE) coordinates of (0.532 1, 0.460 1) and a color purity up to 94.2% among these synthesized materials, but also exhibited splendid thermal stability with the photoluminescence intensity remained 81.6% of its initial value when the temperature was 423 K.
2020, 36(5): 908-920
doi: 10.11862/CJIC.2020.099
Abstract:
Hydration mechanism of hemihydrate calcium sulfate whisker (HCSW) was studied by discussing the change of morphology and crystal form in the storage process in the air, and the regulation of stability by different treatment methods was analyzed. It is found that the hydration of HCSW was caused by -OH group, Ca2+ active site at the surface and the internal channel inside of the whisker. Calcination and diol modification could improve the water resistance of calcium sulfate whisker. The experimental results indicate that after calcination, the hemihydrate calcium sulfate whisker are transformed into anhydrous soluble calcium sulfate whiskers and anhydrous dead calcium sulfate whiskers, the internal channels easy to hydration disappear, and the water resistance is enhanced. In the hydrothermal synthesis process, the addition of binary alcohol was beneficial to the adsorption of alcohol hydroxyl on the (200), (020) and (220) surfaces of HCSW, preventing the adsorption of hydroxyl in H2O molecules on the whisker surface, and further improving the water resistance of the whisker. When the additive was triethylene glycol (TEG) and the concentration was 18.8 mmol·L-1, the water resistance stability of HSCW in the air was not less than 7 days.
Hydration mechanism of hemihydrate calcium sulfate whisker (HCSW) was studied by discussing the change of morphology and crystal form in the storage process in the air, and the regulation of stability by different treatment methods was analyzed. It is found that the hydration of HCSW was caused by -OH group, Ca2+ active site at the surface and the internal channel inside of the whisker. Calcination and diol modification could improve the water resistance of calcium sulfate whisker. The experimental results indicate that after calcination, the hemihydrate calcium sulfate whisker are transformed into anhydrous soluble calcium sulfate whiskers and anhydrous dead calcium sulfate whiskers, the internal channels easy to hydration disappear, and the water resistance is enhanced. In the hydrothermal synthesis process, the addition of binary alcohol was beneficial to the adsorption of alcohol hydroxyl on the (200), (020) and (220) surfaces of HCSW, preventing the adsorption of hydroxyl in H2O molecules on the whisker surface, and further improving the water resistance of the whisker. When the additive was triethylene glycol (TEG) and the concentration was 18.8 mmol·L-1, the water resistance stability of HSCW in the air was not less than 7 days.
2020, 36(5): 921-926
doi: 10.11862/CJIC.2020.097
Abstract:
Two complexes[Tm(dfba)2(phen)(μ2-dfba)]2 (1) and[Yb(dfba)2(phen)(μ2-dfba)]2 (2) (dfba-=2, 6-difluoro-benzoate and phen=1, 10-phenanthroline) were synthesized by the reaction of 2, 6-difluorobenzote and phenan-throline with Tm3+ and Yb3+ ions, respectively. The complexes 1 and 2 were characterized by elemental analysis, FT-IR spectra, thermal gravimetric analysis (TGA) and their crystal structures were determined by single X-ray diffraction. The crystal structures analysis indicated that the complexes 1 and 2 are isostructural. Each Ln3+ is coordinated with two dfba- ligands and one phen molecule to form a[Ln(dfba)2(phen)]+ unit, and the neighboring two[Ln(dfba)2(phen)]+ units are bridged by two different dfba- ligands to form a binuclear molecule, [Ln(dfba)2(phen)(μ2-dfba)]2 (Ln=Tm, Yb).
Two complexes[Tm(dfba)2(phen)(μ2-dfba)]2 (1) and[Yb(dfba)2(phen)(μ2-dfba)]2 (2) (dfba-=2, 6-difluoro-benzoate and phen=1, 10-phenanthroline) were synthesized by the reaction of 2, 6-difluorobenzote and phenan-throline with Tm3+ and Yb3+ ions, respectively. The complexes 1 and 2 were characterized by elemental analysis, FT-IR spectra, thermal gravimetric analysis (TGA) and their crystal structures were determined by single X-ray diffraction. The crystal structures analysis indicated that the complexes 1 and 2 are isostructural. Each Ln3+ is coordinated with two dfba- ligands and one phen molecule to form a[Ln(dfba)2(phen)]+ unit, and the neighboring two[Ln(dfba)2(phen)]+ units are bridged by two different dfba- ligands to form a binuclear molecule, [Ln(dfba)2(phen)(μ2-dfba)]2 (Ln=Tm, Yb).
2020, 36(5): 927-932
doi: 10.11862/CJIC.2020.103
Abstract:
By adjusting the ratio of the solvent components, two mononuclear erbium complexes, [Er(bpad)3]·CH3OH·H2O (1) and[Er(bpad)2(H2O)2]NO3·3H2O (2) (Hbpad=N3-benzoylpyridine-2-carboxamidrazone), have been successfully synthesized. In the mixure of methanol and water solvent (2:1, V/V), yellow crystals of 1 were prepared by solution reaction of Er(NO3)3·6H2O, Hbpad and triethylamine. Interestingly, complex 2 was obtained by the similar way of 1, while the volume ratio of CH3OH to H2O is altered to be 1:2. The resulting complexes were characterized by IR spectrum, elemental analysis. Two complexes are air stable, and can maintain the crystalline integrities at ambient conditions. Crystal structure analysis indicates that the Er(Ⅲ) ions in 1 and 2 present nona-coordinated and octa-coordinated environments in different coordination geometries, respectively. Monocapped square antiprism (C4v) is formed in 1, while biaugmented trigonal prism (C2v) is observed in 2. The direct-current (dc) and alternating-current (ac) magnetic susceptibilities of 1 and 2 have been analyzed as well.
By adjusting the ratio of the solvent components, two mononuclear erbium complexes, [Er(bpad)3]·CH3OH·H2O (1) and[Er(bpad)2(H2O)2]NO3·3H2O (2) (Hbpad=N3-benzoylpyridine-2-carboxamidrazone), have been successfully synthesized. In the mixure of methanol and water solvent (2:1, V/V), yellow crystals of 1 were prepared by solution reaction of Er(NO3)3·6H2O, Hbpad and triethylamine. Interestingly, complex 2 was obtained by the similar way of 1, while the volume ratio of CH3OH to H2O is altered to be 1:2. The resulting complexes were characterized by IR spectrum, elemental analysis. Two complexes are air stable, and can maintain the crystalline integrities at ambient conditions. Crystal structure analysis indicates that the Er(Ⅲ) ions in 1 and 2 present nona-coordinated and octa-coordinated environments in different coordination geometries, respectively. Monocapped square antiprism (C4v) is formed in 1, while biaugmented trigonal prism (C2v) is observed in 2. The direct-current (dc) and alternating-current (ac) magnetic susceptibilities of 1 and 2 have been analyzed as well.
2020, 36(5): 933-940
doi: 10.11862/CJIC.2020.107
Abstract:
An elastic orange-red film (PDMS-PtL1) has been prepared by grafting formyl-containing Pt(Ⅱ) complex Pt(N^C^N)Cl (N^C^N=1, 3-dipyridyl benzene) onto polydimethylsiloxane (PDMS) backbone. The film was highly stretchable (up to 1500% strain) and shows room-temperature self-healing property. Interestingly, stretch-induced luminescent change of the film was observed, where an emission tentatively originating from 3π-π* of separated platinum moieties was detected after stretching. Luminescence quenching is avoided in this elastic film, and the switch of emission state can be realized by changing external forces.
An elastic orange-red film (PDMS-PtL1) has been prepared by grafting formyl-containing Pt(Ⅱ) complex Pt(N^C^N)Cl (N^C^N=1, 3-dipyridyl benzene) onto polydimethylsiloxane (PDMS) backbone. The film was highly stretchable (up to 1500% strain) and shows room-temperature self-healing property. Interestingly, stretch-induced luminescent change of the film was observed, where an emission tentatively originating from 3π-π* of separated platinum moieties was detected after stretching. Luminescence quenching is avoided in this elastic film, and the switch of emission state can be realized by changing external forces.
2020, 36(5): 941-948
doi: 10.11862/CJIC.2020.116
Abstract:
A novel metal-organic framework (MOF), namely[TbL(H2O)2]n (1) (H3L=4, 4', 4″-((1, 3, 5-triazine-2, 4, 6-triyl)tris(sulfanediyl))tribenzoic acid), has been successfully synthesized under solvothermal conditions. All L3- ligands bridge metal ions to form a 3D framework with 1D open channels. In addition, luminescent studies revealed that complex 1 exhibited a unique turn-off luminescent response to Cu2+ and Fe3+ in CH3CN solution.
A novel metal-organic framework (MOF), namely[TbL(H2O)2]n (1) (H3L=4, 4', 4″-((1, 3, 5-triazine-2, 4, 6-triyl)tris(sulfanediyl))tribenzoic acid), has been successfully synthesized under solvothermal conditions. All L3- ligands bridge metal ions to form a 3D framework with 1D open channels. In addition, luminescent studies revealed that complex 1 exhibited a unique turn-off luminescent response to Cu2+ and Fe3+ in CH3CN solution.
2020, 36(5): 949-957
doi: 10.11862/CJIC.2020.106
Abstract:
The as-prepared red phosphorus showed a well-defined complicated porous and nano-sized structure, and the uppermost photocatalytic activity for the hydrothermal treatment 24 h red phosphorus (H-RP24h). The rate constants of the H-RP24h photo-oxidation of rhodamine B (RhB) and photo-reduction of Cr(Ⅵ) were 9.2×10-2 and 3.4×10-2 min-1, 23 and 26 times superior to those of commercial red phosphorus, respectively. Further studies demonstrated that hydrothermal treatment effectively decreased the size of red phosphorus, enhanced light response, and accelerated the detachment of photogenerated electrons and holes (h+), thus increased its photocatalytic activity. It was found that the core reactive species in the photodegradation process were h+ and superoxide ion radicals.
The as-prepared red phosphorus showed a well-defined complicated porous and nano-sized structure, and the uppermost photocatalytic activity for the hydrothermal treatment 24 h red phosphorus (H-RP24h). The rate constants of the H-RP24h photo-oxidation of rhodamine B (RhB) and photo-reduction of Cr(Ⅵ) were 9.2×10-2 and 3.4×10-2 min-1, 23 and 26 times superior to those of commercial red phosphorus, respectively. Further studies demonstrated that hydrothermal treatment effectively decreased the size of red phosphorus, enhanced light response, and accelerated the detachment of photogenerated electrons and holes (h+), thus increased its photocatalytic activity. It was found that the core reactive species in the photodegradation process were h+ and superoxide ion radicals.
2020, 36(5): 958-968
doi: 10.11862/CJIC.2020.102
Abstract:
Three promoters (MgO, CuO, Co2O3) were introduced individually into the commercial Ni-Al alloy powder by impregnation method, and the modified alloys were leached by 10%(w/w) NaOH solution to prepare Raney-Ni catalysts. Effect of promoter on the elemental composition, crystal structure, pore structure, surface morphology and surface acidity of the Ni-Al alloy and the corresponding Raney-Ni catalyst was investigated by energy dispersive X-ray (EDX), X-ray diffraction (XRD), N2 adsorption-desorption, transmission electron microscope (TEM), NH3 temperature programmed desorption (NH3-TPD) and X-ray photoelectron spectroscopy (XPS) methods. Results showed that the element content, specific surface area and surface morphology of the catalyst modified by different promoter proposed significant difference. Large amount of Ni- the active component on the Cu-modified catalyst was detected with the content of about 90%(w/w), showing excellent dispersion, and the catalyst presented small average pore size (3.87 nm). Evaluation results showed that the catalyst displayed well hydrogenation performance, with 1, 4-butenediol (BED) conversion of 100%, both 1, 4-butanediol (BDO) selectivity and yield of 59.62%, which was related to the high Ni content, the moderate amount of acid sites and the small Cu crystal for improving Ni dispersion without serious sintering by the "confinement effect".
Three promoters (MgO, CuO, Co2O3) were introduced individually into the commercial Ni-Al alloy powder by impregnation method, and the modified alloys were leached by 10%(w/w) NaOH solution to prepare Raney-Ni catalysts. Effect of promoter on the elemental composition, crystal structure, pore structure, surface morphology and surface acidity of the Ni-Al alloy and the corresponding Raney-Ni catalyst was investigated by energy dispersive X-ray (EDX), X-ray diffraction (XRD), N2 adsorption-desorption, transmission electron microscope (TEM), NH3 temperature programmed desorption (NH3-TPD) and X-ray photoelectron spectroscopy (XPS) methods. Results showed that the element content, specific surface area and surface morphology of the catalyst modified by different promoter proposed significant difference. Large amount of Ni- the active component on the Cu-modified catalyst was detected with the content of about 90%(w/w), showing excellent dispersion, and the catalyst presented small average pore size (3.87 nm). Evaluation results showed that the catalyst displayed well hydrogenation performance, with 1, 4-butenediol (BED) conversion of 100%, both 1, 4-butanediol (BDO) selectivity and yield of 59.62%, which was related to the high Ni content, the moderate amount of acid sites and the small Cu crystal for improving Ni dispersion without serious sintering by the "confinement effect".
