Login In
2019 Volume 35 Issue 7
2019, 35(7): 1121-1129
doi: 10.11862/CJIC.2019.155
Abstract:
Mesoporous rod-like MnCo2O4 was fabricated via a facile template-free hydrothermal method and subsequent calcination. The crystal structure, surface morphology, pore structure and surface chemical composition were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), N2 adsorption-desorption and X-ray photoelectron spectra (XPS). Characterization results revealed that, in the target MnCo2O4 sample, the mesoporous structure was well-formed, and the pore size distribution was defined in 6 nm. Also, the particular rod-like morphology was obtained in MnCo2O4 with diameters of 100~200 nm and a length of 2~3 μm. Based on these, the MnCo2O4 sample was firstly used as a heterogeneous catalyst in the epoxidation of styrene. Compared with other Co-based and Mn-based catalysts, it exhibited relatively high catalytic activity, the conversion rate of styrene was 95.8%, and the selectivity of styrene oxide was 58.2%. Moreover, after five cycles, the catalytic activity did not change significantly, further confirming the stability of MnCo2O4. Meanwhile, the effects of main reaction parameters (reaction time, reaction temperature, the molar ratio of styrene to tert-butyl hydroperoxide (TBHP)) on the catalytic activity of mesoporous rod-like MnCo2O4 were systematically investigated.
Mesoporous rod-like MnCo2O4 was fabricated via a facile template-free hydrothermal method and subsequent calcination. The crystal structure, surface morphology, pore structure and surface chemical composition were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), N2 adsorption-desorption and X-ray photoelectron spectra (XPS). Characterization results revealed that, in the target MnCo2O4 sample, the mesoporous structure was well-formed, and the pore size distribution was defined in 6 nm. Also, the particular rod-like morphology was obtained in MnCo2O4 with diameters of 100~200 nm and a length of 2~3 μm. Based on these, the MnCo2O4 sample was firstly used as a heterogeneous catalyst in the epoxidation of styrene. Compared with other Co-based and Mn-based catalysts, it exhibited relatively high catalytic activity, the conversion rate of styrene was 95.8%, and the selectivity of styrene oxide was 58.2%. Moreover, after five cycles, the catalytic activity did not change significantly, further confirming the stability of MnCo2O4. Meanwhile, the effects of main reaction parameters (reaction time, reaction temperature, the molar ratio of styrene to tert-butyl hydroperoxide (TBHP)) on the catalytic activity of mesoporous rod-like MnCo2O4 were systematically investigated.
2019, 35(7): 1248-1254
doi: 10.11862/CJIC.2019.094
Abstract:
Two 1D cobalt(Ⅱ) and 2D nickel(Ⅱ) coordination polymers, namely[Co(μ2-H2btc)2(4, 4'-bipy)2]n (1) and {[Ni3(μ4-dppa)2(H2O)6]·2H2O}n (2), have been constructed hydrothermally using H3btc (H3btc=biphenyl-2, 4, 4'-tricarboxylic acid), H3dppa (H3dppa=5-(3, 4-dicarboxylphenyl)picolinic acid), 4, 4'-bipy(4, 4'-bipy=4, 4'-bipyridine), and cobalt or nickel chlorides. Single-crystal X-ray diffraction analyses reveal that both compounds crystallize in the triclinic system, space group\begin{document}$ P\bar 1$\end{document}
Two 1D cobalt(Ⅱ) and 2D nickel(Ⅱ) coordination polymers, namely[Co(μ2-H2btc)2(4, 4'-bipy)2]n (1) and {[Ni3(μ4-dppa)2(H2O)6]·2H2O}n (2), have been constructed hydrothermally using H3btc (H3btc=biphenyl-2, 4, 4'-tricarboxylic acid), H3dppa (H3dppa=5-(3, 4-dicarboxylphenyl)picolinic acid), 4, 4'-bipy(4, 4'-bipy=4, 4'-bipyridine), and cobalt or nickel chlorides. Single-crystal X-ray diffraction analyses reveal that both compounds crystallize in the triclinic system, space group
2019, 35(7): 1255-1266
doi: 10.11862/CJIC.2019.141
Abstract:
Sulfonated polystyrene (PS) microspheres have been used as template to produce mesoporous Fe-MIL-88B-NH2 spherical shell with open pore. Based on the shell a novel visible-light-active AgI modified microsphere Fe-MIL-88B-NH2 was prepared by in situ reaction method. The photocatalytic activity of the resulted AgI@Fe-MIL-88B-NH2 composite was enhanced significantly as compared with pure AgI and Fe-MIL-88B-NH2, which can be derived from the enhanced adsorption capacity and the promoted separation of charge carriers. The possible mechanism for the separation of charge carriers can be attributed to the formation of a redox-mediator-free direct Z-scheme system which causes the photogenerated electrons to migrate from CB of Fe-MIL-88B-NH2 to VB of AgI, thus yielding more active·O2- and·OH.
Sulfonated polystyrene (PS) microspheres have been used as template to produce mesoporous Fe-MIL-88B-NH2 spherical shell with open pore. Based on the shell a novel visible-light-active AgI modified microsphere Fe-MIL-88B-NH2 was prepared by in situ reaction method. The photocatalytic activity of the resulted AgI@Fe-MIL-88B-NH2 composite was enhanced significantly as compared with pure AgI and Fe-MIL-88B-NH2, which can be derived from the enhanced adsorption capacity and the promoted separation of charge carriers. The possible mechanism for the separation of charge carriers can be attributed to the formation of a redox-mediator-free direct Z-scheme system which causes the photogenerated electrons to migrate from CB of Fe-MIL-88B-NH2 to VB of AgI, thus yielding more active·O2- and·OH.
2019, 35(7): 1267-1274
doi: 10.11862/CJIC.2019.137
Abstract:
By using a methyl-functionalized N-donor ligand, a water-stable zinc-based MOF {[Zn(BDC)(dmbpy)]·4H2O}n (1) (BDC=isophthalate, dmbpy=3, 3'-dimethyl-4, 4'-bipyridine) was synthesized and structurally character-ized. TGA and PXRD results show high thermal and water stability for 1.1 exhibits a 2D (4, 4) net with channels of 0.92 nm×0.83 nm and 0.82 nm×0.39 nm along the b axis, respectively. De-solvated 1 adsorbs around 14.2%(w/w) 5-fluorouracil (5-FU) and the cumulative release value of 5-FU after 70 h was about 94.5% and 99% in PBS (pH=7.4 and pH=6.0) at 37℃, respectively. The in vivo zebrafish toxicity tests and in vitro MTT assays of 1 at different concentrations results reveal that 1 is nontoxic (cell viability>80%) up to concentrations of 500 μg·mL-1.
By using a methyl-functionalized N-donor ligand, a water-stable zinc-based MOF {[Zn(BDC)(dmbpy)]·4H2O}n (1) (BDC=isophthalate, dmbpy=3, 3'-dimethyl-4, 4'-bipyridine) was synthesized and structurally character-ized. TGA and PXRD results show high thermal and water stability for 1.1 exhibits a 2D (4, 4) net with channels of 0.92 nm×0.83 nm and 0.82 nm×0.39 nm along the b axis, respectively. De-solvated 1 adsorbs around 14.2%(w/w) 5-fluorouracil (5-FU) and the cumulative release value of 5-FU after 70 h was about 94.5% and 99% in PBS (pH=7.4 and pH=6.0) at 37℃, respectively. The in vivo zebrafish toxicity tests and in vitro MTT assays of 1 at different concentrations results reveal that 1 is nontoxic (cell viability>80%) up to concentrations of 500 μg·mL-1.
2019, 35(7): 1275-1282
doi: 10.11862/CJIC.2019.150
Abstract:
Two new complexes[Cd(nba)2(mbix)]2 (1) and[Cd((bib)2Br2]n (2) (Hnba=4-nitrobenzoic acid, mbix=1, 3-bis(imidazol-1-ylmethyl)benzene, bib=1, 4-bis(imidazol-1-yl)-butane) have been hydrothermally synthesized and structurally characterized by elemental analysis, IR spectrum, fluorescence spectrum, single-crystal and powder X-ray diffraction. Complex 1 exhibits zero-dimensional framework and display three-dimensional supramolecular network via π-π stacking interactions. Complex 2 shows 2D network with (4, 4) topology. Moreover, we analyzed natural bond orbital (NBO) of 1 and 2 by the PBE0/LANL2DZ method built in Gaussian 03 Program. The calculation results show the obvious covalent interaction between the coordinated atoms and Cd(Ⅱ) ions.
Two new complexes[Cd(nba)2(mbix)]2 (1) and[Cd((bib)2Br2]n (2) (Hnba=4-nitrobenzoic acid, mbix=1, 3-bis(imidazol-1-ylmethyl)benzene, bib=1, 4-bis(imidazol-1-yl)-butane) have been hydrothermally synthesized and structurally characterized by elemental analysis, IR spectrum, fluorescence spectrum, single-crystal and powder X-ray diffraction. Complex 1 exhibits zero-dimensional framework and display three-dimensional supramolecular network via π-π stacking interactions. Complex 2 shows 2D network with (4, 4) topology. Moreover, we analyzed natural bond orbital (NBO) of 1 and 2 by the PBE0/LANL2DZ method built in Gaussian 03 Program. The calculation results show the obvious covalent interaction between the coordinated atoms and Cd(Ⅱ) ions.
2019, 35(7): 1283-1294
doi: 10.11862/CJIC.2019.158
Abstract:
Two new homo-trinuclear Ni(Ⅱ) and Zn(Ⅱ) complexes, [Ni3(L)(μ-OAc)2(CH3OH)3]·CH3OH·0.25CHCl3 (1) and[Zn3(L)(μ-OAc)2(CH3OH) (H2O)]·2CH3OH (2) with a newly synthesized C-type bis(salamo)-like ligand H4L have been prepared and structurally characterized. The structures of complexes 1 and 2 were fully characterized by elemental analyses, FT-IR, UV-visible spectroscopy, single crystal X-ray crystallography, thermal analyses (TGA) and Hirshfeld surfaces analyses, and their luminescence properties were also discussed. The X-ray crystallography analyses demonstrated that complex 1 is an asymmetric trinuclear structure, and all Ni(Ⅱ) ions are hexa-coordinated, forming distorted octahedral geometries. Meanwhile, complex 2 is a symmetric trinuclear structure, the central Zn2 ion is hexa-coordinated and possesses a distorted octahedral coordination geometry. However, the terminal Zn1 and Zn1#1 ions are both penta-coordinated environments and adopt distorted trigonal bipyramidal geometries. In addition, 3D supramolecular architectures of complexes 1 and 2 were formed by hydrogen bonding and C-H…π interactions. Most importantly, the fluorescent property of complex 2 is totally different from that of complex 2.
Two new homo-trinuclear Ni(Ⅱ) and Zn(Ⅱ) complexes, [Ni3(L)(μ-OAc)2(CH3OH)3]·CH3OH·0.25CHCl3 (1) and[Zn3(L)(μ-OAc)2(CH3OH) (H2O)]·2CH3OH (2) with a newly synthesized C-type bis(salamo)-like ligand H4L have been prepared and structurally characterized. The structures of complexes 1 and 2 were fully characterized by elemental analyses, FT-IR, UV-visible spectroscopy, single crystal X-ray crystallography, thermal analyses (TGA) and Hirshfeld surfaces analyses, and their luminescence properties were also discussed. The X-ray crystallography analyses demonstrated that complex 1 is an asymmetric trinuclear structure, and all Ni(Ⅱ) ions are hexa-coordinated, forming distorted octahedral geometries. Meanwhile, complex 2 is a symmetric trinuclear structure, the central Zn2 ion is hexa-coordinated and possesses a distorted octahedral coordination geometry. However, the terminal Zn1 and Zn1#1 ions are both penta-coordinated environments and adopt distorted trigonal bipyramidal geometries. In addition, 3D supramolecular architectures of complexes 1 and 2 were formed by hydrogen bonding and C-H…π interactions. Most importantly, the fluorescent property of complex 2 is totally different from that of complex 2.
2019, 35(7): 1295-1300
doi: 10.11862/CJIC.2019.157
Abstract:
Two complexes, namely, [Sn(L)Ph2Cl]·0.25CH3OH (1) and[Ag(HL)(NO3)]·CH3OH (2) based on HL (HL=N-((quinolin-8-yl)methylene)salicylhydrazide) were synthesized and characterized by X-ray diffraction analyses. The result shows that the Sn(Ⅳ) ion in complex 1 coordinates with one anionic hydrazone ligand with ON2 donor set, one chloride ion and two carbon atoms coming from two phenyl groups, thus giving a distorted octahedral coordination geometry. The Ag(Ⅰ) ion in complex 2 that displays a distorted square pyramid coordination geometry is surrounded by one tridentate hydrazone ligand and one bidentate nitrate anions. In addition, the fluorescence spectra indicate that the interactions of the complexes with DNA are stronger than ligand HL.
Two complexes, namely, [Sn(L)Ph2Cl]·0.25CH3OH (1) and[Ag(HL)(NO3)]·CH3OH (2) based on HL (HL=N-((quinolin-8-yl)methylene)salicylhydrazide) were synthesized and characterized by X-ray diffraction analyses. The result shows that the Sn(Ⅳ) ion in complex 1 coordinates with one anionic hydrazone ligand with ON2 donor set, one chloride ion and two carbon atoms coming from two phenyl groups, thus giving a distorted octahedral coordination geometry. The Ag(Ⅰ) ion in complex 2 that displays a distorted square pyramid coordination geometry is surrounded by one tridentate hydrazone ligand and one bidentate nitrate anions. In addition, the fluorescence spectra indicate that the interactions of the complexes with DNA are stronger than ligand HL.
2019, 35(7): 1301-1311
doi: 10.11862/CJIC.2019.160
Abstract:
The fluorine derivatives of calix[4]arene, C64H52F12O4 (1), C60H52F4O4 (2), C68H48F24O4 (3), were synthesized, and their cone conformations were proved by single crystal X-ray diffraction and 1H NMR spectroscopy. Their recognition behaviors were evaluated towards a variety of metal ions in mixed solvent. The UV-Vis absorption and fluorescence spectroscopy were measured and confirmed that copper ions resulted in fluorescence quenching of compounds 1~3, while other ions such as Na+, K+, Cs+, Mg2+, Ca2+, Ba2+, Fe3+, Cd2+, Mn2+, Co2+, Ni2+, Zn2+ exerted hardly significant impact on the UV-Vis absorption and fluorescence intensity of 1~3, exhibiting high selectivity of compounds 1~3 to copper ions.
The fluorine derivatives of calix[4]arene, C64H52F12O4 (1), C60H52F4O4 (2), C68H48F24O4 (3), were synthesized, and their cone conformations were proved by single crystal X-ray diffraction and 1H NMR spectroscopy. Their recognition behaviors were evaluated towards a variety of metal ions in mixed solvent. The UV-Vis absorption and fluorescence spectroscopy were measured and confirmed that copper ions resulted in fluorescence quenching of compounds 1~3, while other ions such as Na+, K+, Cs+, Mg2+, Ca2+, Ba2+, Fe3+, Cd2+, Mn2+, Co2+, Ni2+, Zn2+ exerted hardly significant impact on the UV-Vis absorption and fluorescence intensity of 1~3, exhibiting high selectivity of compounds 1~3 to copper ions.
2019, 35(7): 1312-1320
doi: 10.11862/CJIC.2019.143
Abstract:
A novel binuclear calcium complex[Ca2L2(NO3)2] (1) and a mononuclear cadmium complex[Cd(HL)(NO3)2] (2) have been successfully synthesized by using 2-(N, N-di(2-pyridylmethyl)aminomethyl)-6-aldehydo-4-methylphenol (HL) as a ligand. Complex 2 can be transformed to a binuclear cadmium complex[Cd2L2(NO3)2]·H2O (3) under basic conditions. Complexes 1~3 have been characterized by FT-IR, ESI-MS, elemental analysis and single-crystal X-ray diffraction. Both 1 and 3 crystallize in monoclinic system, but with space group P21/c and C2/c, respectively, while 2 in triclinic system with space group P1. X-ray crystallography analysis reveals that 1 has a bi-calcium unit[Ca2O2] bridged by two phenolato O atoms, and each eight-coordinated Ca(Ⅱ) cation shows a distorted dodecahedron configuration[CaN3O5] with three N atoms and one phenolato O atom from one L-, one phenolato O atom and an aldehyde O atom from another L- ligand, and two O atoms from one nitrate. 2 is a mononuclear cadmium complex and Cd(Ⅱ) cation is eight-coordinated by three N atoms and one phenol O atom from HL ligand and four O atoms from two nitrates to show a distorted dodecahedron configuration[CdN3O5], whereas the aldehyde group does not take part in coordination. 3 contains a bi-cadmium unit[Cd2O2] bridged by two phenolato O atoms, and each seven-coordinated Cd(Ⅱ) cation shows a distorted monocapped trigonal prism configuration[CdN3O4] with three N atoms and one phenolato O atom from one L-, one phenolato O atom and an aldehyde O atom from another L- ligand, and one O atom from one nitrate.
A novel binuclear calcium complex[Ca2L2(NO3)2] (1) and a mononuclear cadmium complex[Cd(HL)(NO3)2] (2) have been successfully synthesized by using 2-(N, N-di(2-pyridylmethyl)aminomethyl)-6-aldehydo-4-methylphenol (HL) as a ligand. Complex 2 can be transformed to a binuclear cadmium complex[Cd2L2(NO3)2]·H2O (3) under basic conditions. Complexes 1~3 have been characterized by FT-IR, ESI-MS, elemental analysis and single-crystal X-ray diffraction. Both 1 and 3 crystallize in monoclinic system, but with space group P21/c and C2/c, respectively, while 2 in triclinic system with space group P1. X-ray crystallography analysis reveals that 1 has a bi-calcium unit[Ca2O2] bridged by two phenolato O atoms, and each eight-coordinated Ca(Ⅱ) cation shows a distorted dodecahedron configuration[CaN3O5] with three N atoms and one phenolato O atom from one L-, one phenolato O atom and an aldehyde O atom from another L- ligand, and two O atoms from one nitrate. 2 is a mononuclear cadmium complex and Cd(Ⅱ) cation is eight-coordinated by three N atoms and one phenol O atom from HL ligand and four O atoms from two nitrates to show a distorted dodecahedron configuration[CdN3O5], whereas the aldehyde group does not take part in coordination. 3 contains a bi-cadmium unit[Cd2O2] bridged by two phenolato O atoms, and each seven-coordinated Cd(Ⅱ) cation shows a distorted monocapped trigonal prism configuration[CdN3O4] with three N atoms and one phenolato O atom from one L-, one phenolato O atom and an aldehyde O atom from another L- ligand, and one O atom from one nitrate.
2019, 35(7): 1130-1138
doi: 10.11862/CJIC.2019.154
Abstract:
Based on o-carboxybenzaldehyde-1, 3-diaminopropane bis-Schiff base (L1) and o-carboxybenzaldehyde-ethylenediamine bis-Schiff base (L2), two copper(Ⅱ) complexes, namely[Cu(L1)(CH3OH)] (1) and[Cu2(L)2]·2H2O·CH3OH (2), have been prepared by solvothermal synthesis method, where methyl phthalate ethylenediamine bis-Schiff base (L) was formed by the addition reaction of ligand L2 with methanol. The crystal structure of ligand L2 and complex 1, 2 was characterized by X-ray single crystal diffraction. The structural analysis indicates that L2 is o-carboxybenzaldehyde ethylenediamine bis-Schiff base ligand, which belongs to monoclinic system, I2/a space group. Complex 1 belongs to the orthorhombic system, Pbca space group, and Cu(Ⅱ) is coordinated with the bis-Schiff base ligand L1 and a methanol molecule to form a penta-coordinated tetragonal[CuO3N2] configuration. Complex 2 belongs to the triclinic system, P1 space group, and Cu(Ⅱ) is coordinated with two nitrogen atoms and three oxygen atoms of the ligand L to form a penta-coordinated twisted triangular bipyramid[CuO3N2] configuration, and the di-nuclear copper structure is formed by bridging a carboxyl oxygen atom. Complexes 1, 2 both have a 3D structure construed by highly stable hydrogen bonds. The structure characterization and properties of ligands L1, L2 and complexes 1, 2 were studied by IR, elemental analyses, UV, fluorescence and thermogravimetry. The results indicate that bis-Schiff base L1, L2 and complexes 1, 2 have good fluorescence properties and thermal stability. Moreover, complexes 1 and 2 showed strong fluorescence emission at 327 and 323 nm, respectively.
Based on o-carboxybenzaldehyde-1, 3-diaminopropane bis-Schiff base (L1) and o-carboxybenzaldehyde-ethylenediamine bis-Schiff base (L2), two copper(Ⅱ) complexes, namely[Cu(L1)(CH3OH)] (1) and[Cu2(L)2]·2H2O·CH3OH (2), have been prepared by solvothermal synthesis method, where methyl phthalate ethylenediamine bis-Schiff base (L) was formed by the addition reaction of ligand L2 with methanol. The crystal structure of ligand L2 and complex 1, 2 was characterized by X-ray single crystal diffraction. The structural analysis indicates that L2 is o-carboxybenzaldehyde ethylenediamine bis-Schiff base ligand, which belongs to monoclinic system, I2/a space group. Complex 1 belongs to the orthorhombic system, Pbca space group, and Cu(Ⅱ) is coordinated with the bis-Schiff base ligand L1 and a methanol molecule to form a penta-coordinated tetragonal[CuO3N2] configuration. Complex 2 belongs to the triclinic system, P1 space group, and Cu(Ⅱ) is coordinated with two nitrogen atoms and three oxygen atoms of the ligand L to form a penta-coordinated twisted triangular bipyramid[CuO3N2] configuration, and the di-nuclear copper structure is formed by bridging a carboxyl oxygen atom. Complexes 1, 2 both have a 3D structure construed by highly stable hydrogen bonds. The structure characterization and properties of ligands L1, L2 and complexes 1, 2 were studied by IR, elemental analyses, UV, fluorescence and thermogravimetry. The results indicate that bis-Schiff base L1, L2 and complexes 1, 2 have good fluorescence properties and thermal stability. Moreover, complexes 1 and 2 showed strong fluorescence emission at 327 and 323 nm, respectively.
2019, 35(7): 1139-1147
doi: 10.11862/CJIC.2019.140
Abstract:
Precursor[Ni0.85Co0.08Mn0.07](OH)2 with continuous concentration gradient change of metal elements were prepared by a continuous crystallization method. The new gradient composite Cathode material Li[Ni0.85Co0.08Mn0.07]O2 was synthesized by sintering the mixture of as-prepared precursor and LiOH·H2O in O2. X-ray diffraction results indicated a low degree of cationic miscibility and a better layered structure. Scanning electronic microscopy showed the gradient material had a perfect spherical morphology. Particle size distribution was relatively concentrated in 11.5~12 μm. The line scan test of elements on the cross section area of coating shell showed that the main elements of the materials changed gradiently. From the center to the outer surface, the content of nickel became lower, while that of cobalt and manganese were higher. The initial discharge capacity was 204.3 mAh·g-1 at 0.1C rate between 2.8 and 4.3 V. At 1C rate, its capacity was 185.3 mAh·g-1 and retained 164.7 mAh·g-1 (89.17%) after 100 cycles. When cycled at 55℃, the capacity of 1C rate was 202.7 mAh·g-1 and retained 85.84% after 100 cycles, indicating good electrochemical capacity and cycling stability.
Precursor[Ni0.85Co0.08Mn0.07](OH)2 with continuous concentration gradient change of metal elements were prepared by a continuous crystallization method. The new gradient composite Cathode material Li[Ni0.85Co0.08Mn0.07]O2 was synthesized by sintering the mixture of as-prepared precursor and LiOH·H2O in O2. X-ray diffraction results indicated a low degree of cationic miscibility and a better layered structure. Scanning electronic microscopy showed the gradient material had a perfect spherical morphology. Particle size distribution was relatively concentrated in 11.5~12 μm. The line scan test of elements on the cross section area of coating shell showed that the main elements of the materials changed gradiently. From the center to the outer surface, the content of nickel became lower, while that of cobalt and manganese were higher. The initial discharge capacity was 204.3 mAh·g-1 at 0.1C rate between 2.8 and 4.3 V. At 1C rate, its capacity was 185.3 mAh·g-1 and retained 164.7 mAh·g-1 (89.17%) after 100 cycles. When cycled at 55℃, the capacity of 1C rate was 202.7 mAh·g-1 and retained 85.84% after 100 cycles, indicating good electrochemical capacity and cycling stability.
2019, 35(7): 1148-1154
doi: 10.11862/CJIC.2019.149
Abstract:
Two complexes[Ni(3, 3'-dpdc)(dpp)]n (1) and[Ni(2, 2'-dpdc)(phen)(H2O)2]n (2) were obtained under different reaction conditions (2, 2'-H2dpdc=2, 2'-biphenyldicarboxylic acid, 3, 3'-H2dpdc=3, 3'-biphenyldicarboxylic acid, phen=1, 10-phenanthroline, dpp=1, 3-bis(4-pyridyl)propane), and their structures were characterized by X-ray single crystal diffraction. Complex 1 belongs to monoclinic system, space group P21/c. It has two-dimensional grid structure and the coordination environment of Ni(Ⅱ) ion is[NiO2N4]. The two carboxyl groups of the 3, 3'-dpdc ligand coordinate to the Ni(Ⅱ) ion by a bidentate chelate coordination mode to form a Ni-(3, 3'-dpdc) one-dimensional chain structure, and the dpp ligand adopts a single nitrogen atom bridged coordination mode to connect two Ni(Ⅱ)) ions to form a Ni-dpp one-dimensional chain. The two chains penetrate each other to form a two-dimensional grid structure. The two-dimensional grid structure is stacked into a three-dimensional structure by C15D-H15…O2, C21-H21A…O1 hydrogen bonding. Complex 2 belongs to orthorhombic crystal system, space group P212121. The complex shows a one-dimensional zigzag structure. The coordination envrionment of Ni(Ⅱ) ion is[NiO4N2]. The two carboxyl groups of 2, 2'-dpdc adopt a single-tooth bridged coordination mode. The adjacent Ni(Ⅱ) ions are linked by 2, 2'-dpdc ligand to form the Ni-2, 2'-dpdc zigzag chain structure, and the chains are connected to form a three-dimensional supramolecular structure by O-H…O and C-H…π. The photocatalytic degradation of the organic dye rhodamine B by two complexes was investigated. The results show that complexes can degrade rhodamine B efficiently.
Two complexes[Ni(3, 3'-dpdc)(dpp)]n (1) and[Ni(2, 2'-dpdc)(phen)(H2O)2]n (2) were obtained under different reaction conditions (2, 2'-H2dpdc=2, 2'-biphenyldicarboxylic acid, 3, 3'-H2dpdc=3, 3'-biphenyldicarboxylic acid, phen=1, 10-phenanthroline, dpp=1, 3-bis(4-pyridyl)propane), and their structures were characterized by X-ray single crystal diffraction. Complex 1 belongs to monoclinic system, space group P21/c. It has two-dimensional grid structure and the coordination environment of Ni(Ⅱ) ion is[NiO2N4]. The two carboxyl groups of the 3, 3'-dpdc ligand coordinate to the Ni(Ⅱ) ion by a bidentate chelate coordination mode to form a Ni-(3, 3'-dpdc) one-dimensional chain structure, and the dpp ligand adopts a single nitrogen atom bridged coordination mode to connect two Ni(Ⅱ)) ions to form a Ni-dpp one-dimensional chain. The two chains penetrate each other to form a two-dimensional grid structure. The two-dimensional grid structure is stacked into a three-dimensional structure by C15D-H15…O2, C21-H21A…O1 hydrogen bonding. Complex 2 belongs to orthorhombic crystal system, space group P212121. The complex shows a one-dimensional zigzag structure. The coordination envrionment of Ni(Ⅱ) ion is[NiO4N2]. The two carboxyl groups of 2, 2'-dpdc adopt a single-tooth bridged coordination mode. The adjacent Ni(Ⅱ) ions are linked by 2, 2'-dpdc ligand to form the Ni-2, 2'-dpdc zigzag chain structure, and the chains are connected to form a three-dimensional supramolecular structure by O-H…O and C-H…π. The photocatalytic degradation of the organic dye rhodamine B by two complexes was investigated. The results show that complexes can degrade rhodamine B efficiently.
2019, 35(7): 1155-1162
doi: 10.11862/CJIC.2019.139
Abstract:
The porous Fe3O4@mMoO3 multifunctional core-shell nanoparticles were used to microwave-triggered controlled-release drug delivery systems. We also studied its magnetic-microwave heat transfer property and large specific surface area. We chose ibuprofen (IBU) as a model drug to evaluate the loading and release function of the Fe3O4@mMoO3 nanoparticles, and used a direct precipitation method and thermal decomposition of C19H42BrN (CTAB) template method to synthesize core-shell structured Fe3O4@mMoO3 nanoparticles. The specific surface areas were calculated by the Brunauer-Emmett-Teller (BET) method. The drug loading and controlled release of the Fe3O4@mMoO3 triggered by microwave was determined with ultraviolet-visible spectroscopic analysis. The Fe3O4@mMoO3 nanoparticles possessed high surface area of 94 cm2·g-1, provided large accessible pore diameter of 2.5 nm for adsorption of drug molecules, high magnetization saturation value of 42.3 emu·g-1 for drug targeting under foreign magnetic fields, and quickly converted electromagnetic energy into thermal energy for controlled release by microwave-triggered which was caused by mMoO3 shell. The release amount of IBU was over 90% within 90 s under microwave discontinuous irradiation and outclassed that under the only stirring. This multifunctional material showed good performance for targeting delivery and microwave controlled release of anticancer drugs. The porous shell and the introduction of absorbing material not only increased the drug loading efficiency of the nanoparticles but also realized the microwave-stimulated anticancer drug controlled release.
The porous Fe3O4@mMoO3 multifunctional core-shell nanoparticles were used to microwave-triggered controlled-release drug delivery systems. We also studied its magnetic-microwave heat transfer property and large specific surface area. We chose ibuprofen (IBU) as a model drug to evaluate the loading and release function of the Fe3O4@mMoO3 nanoparticles, and used a direct precipitation method and thermal decomposition of C19H42BrN (CTAB) template method to synthesize core-shell structured Fe3O4@mMoO3 nanoparticles. The specific surface areas were calculated by the Brunauer-Emmett-Teller (BET) method. The drug loading and controlled release of the Fe3O4@mMoO3 triggered by microwave was determined with ultraviolet-visible spectroscopic analysis. The Fe3O4@mMoO3 nanoparticles possessed high surface area of 94 cm2·g-1, provided large accessible pore diameter of 2.5 nm for adsorption of drug molecules, high magnetization saturation value of 42.3 emu·g-1 for drug targeting under foreign magnetic fields, and quickly converted electromagnetic energy into thermal energy for controlled release by microwave-triggered which was caused by mMoO3 shell. The release amount of IBU was over 90% within 90 s under microwave discontinuous irradiation and outclassed that under the only stirring. This multifunctional material showed good performance for targeting delivery and microwave controlled release of anticancer drugs. The porous shell and the introduction of absorbing material not only increased the drug loading efficiency of the nanoparticles but also realized the microwave-stimulated anticancer drug controlled release.
2019, 35(7): 1163-1168
doi: 10.11862/CJIC.2019.124
Abstract:
Graphene/SnO2 (G/SnO2) composites were prepared by solvothermal method and characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy, etc. The effect of the amount of graphene and the solvothermal temperature on the gas sensing properties of G/SnO2 composites was investigated. The results showed that graphene supernatant can regulate the growth of SnO2 crystals. The G/SnO2 nanomaterial obtained with 1 mL supernatant and heat treatment at 160℃ for 10 h had good response and selectivity to ammonia at room temperature. The response to 1 000 μL·L-1 ammonia gas reached 266.4 and the detection limit reached 0.01 μL·L-1.
Graphene/SnO2 (G/SnO2) composites were prepared by solvothermal method and characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy, etc. The effect of the amount of graphene and the solvothermal temperature on the gas sensing properties of G/SnO2 composites was investigated. The results showed that graphene supernatant can regulate the growth of SnO2 crystals. The G/SnO2 nanomaterial obtained with 1 mL supernatant and heat treatment at 160℃ for 10 h had good response and selectivity to ammonia at room temperature. The response to 1 000 μL·L-1 ammonia gas reached 266.4 and the detection limit reached 0.01 μL·L-1.
2019, 35(7): 1169-1175
doi: 10.11862/CJIC.2019.147
Abstract:
W-doping LiNiO2 (LiNi1-xWxO2, x=1% and 3%) cathode materials were prepared by sol-gel method. The effects of W-doping on electrochemical performances of LiNiO2 materials were studied. The results showed that W-doping significantly improved the cycle performance of LiNiO2 during charge-discharge process. The capacity retention of the LiNi0.99W0.01O2 was 62.51% at a current density of 100 mA·g-1 after 400 cycles in the voltage of 2.5~4.5 V, while the LiNiO2 was only 47.06%. In addition, the rate performance of LiNiO2 was improved at the same current rates.
W-doping LiNiO2 (LiNi1-xWxO2, x=1% and 3%) cathode materials were prepared by sol-gel method. The effects of W-doping on electrochemical performances of LiNiO2 materials were studied. The results showed that W-doping significantly improved the cycle performance of LiNiO2 during charge-discharge process. The capacity retention of the LiNi0.99W0.01O2 was 62.51% at a current density of 100 mA·g-1 after 400 cycles in the voltage of 2.5~4.5 V, while the LiNiO2 was only 47.06%. In addition, the rate performance of LiNiO2 was improved at the same current rates.
2019, 35(7): 1176-1182
doi: 10.11862/CJIC.2019.116
Abstract:
Poly(3, 4-ethylenedioxothiophene) (PEDOT)/graphene/Ti electrodes were synthesized via the two-step method. The graphene was grown on Ti substrate by the direct current arc plasma jet chemical vapor deposition technique, and PEDOT was deposited on the surface of graphene by electrochemical oxidation polymerization. The PEDOT layers with nanowires or foam morphologies were synthesized by adjusting the polymerization cycles. The fabricated PEDOT/graphene/Ti electrodes demonstrated high specific capacitance and good coulombic efficiency in 0.1 mol·L-1 KCl electrolyte. The maximum potential window of the 400-cycle PEDOT/graphene/Ti electrode was 1.4 V. The specific capacitance calculated from the CV curve at a scan rate of 10 mV·s-1 was about 269.6 mF·cm-2 (0 to 1.2 V). The specific capacitance of the 400-cycle PEDOT/graphene/Ti electrode was calculated to be 42 times larger than the PEDOT/Ti electrode.
Poly(3, 4-ethylenedioxothiophene) (PEDOT)/graphene/Ti electrodes were synthesized via the two-step method. The graphene was grown on Ti substrate by the direct current arc plasma jet chemical vapor deposition technique, and PEDOT was deposited on the surface of graphene by electrochemical oxidation polymerization. The PEDOT layers with nanowires or foam morphologies were synthesized by adjusting the polymerization cycles. The fabricated PEDOT/graphene/Ti electrodes demonstrated high specific capacitance and good coulombic efficiency in 0.1 mol·L-1 KCl electrolyte. The maximum potential window of the 400-cycle PEDOT/graphene/Ti electrode was 1.4 V. The specific capacitance calculated from the CV curve at a scan rate of 10 mV·s-1 was about 269.6 mF·cm-2 (0 to 1.2 V). The specific capacitance of the 400-cycle PEDOT/graphene/Ti electrode was calculated to be 42 times larger than the PEDOT/Ti electrode.
2019, 35(7): 1183-1187
doi: 10.11862/CJIC.2019.136
Abstract:
Single ion magnets based on Dy(Ⅲ) complexes are of particular interest due to their doubly degenerate high spin ground state and strong axial single-ion anisotropy. Herein, a new dinuclear dysprosium (Dy) complex[Dy2(PY)(TTA)6] (1) was prepared by the reaction between a chiral pinene pyridyl pyrazine ligand (PY) and β-diketone Dy compound (Dy(TTA)3). X-ray single crystal diffraction characterization of the obtained complex indicated that the configuration inversion of chiral pinene group occurred during the crystal growth, which results in a central symmetry configuration. The temperature-dependent susceptibility test revealed that the prepared Dy complex exhibits slow magnetic relaxation in the absence of external dc magnetic field.
Single ion magnets based on Dy(Ⅲ) complexes are of particular interest due to their doubly degenerate high spin ground state and strong axial single-ion anisotropy. Herein, a new dinuclear dysprosium (Dy) complex[Dy2(PY)(TTA)6] (1) was prepared by the reaction between a chiral pinene pyridyl pyrazine ligand (PY) and β-diketone Dy compound (Dy(TTA)3). X-ray single crystal diffraction characterization of the obtained complex indicated that the configuration inversion of chiral pinene group occurred during the crystal growth, which results in a central symmetry configuration. The temperature-dependent susceptibility test revealed that the prepared Dy complex exhibits slow magnetic relaxation in the absence of external dc magnetic field.
2019, 35(7): 1188-1194
doi: 10.11862/CJIC.2019.146
Abstract:
In order to study the origin of ferromagnetism of spherical carbon structure, we prepared two kinds of hydrogenated carbon nanospheres(HCNSs) by solvothermal synthesis at 80 and 120℃, respectively, using Na as reducing agent and chloroform as raw material. Then we performed systematic characterization on them. According to SEM images, we found that the average particle size of HCNSs synthesized at 80℃ was 150 nm, while the average particle size of HCNSs synthesized at 120℃ was 300 nm, and the dispersion of the latter is better than that of the former. The TEM images showed that both hydrogenated carbon nanospheres were in the form of onion-like graphite, and the graphite layer was distributed in a wave shape on the curved surface of the carbon sphere. It can be seen from the X-ray photoelectron spectroscopy that the degree of hydrogenation of the hydrogenated carbon nanospheres at 80℃ is higher, which is consistent with the results of elemental analysis. The infrared spectroscopy (IR) of the HCNSs indicates that the two nanospheres have relative low carbon-hydrogen bond content. The Raman spectra of the HCNSs indicates that the obtained HCNSs have high degree of disorder and poor crystallinity. We magnetically characterized the HCNSs at room temperature, and the results show that both the HCNSs have ferromagnetism. The negative Gaussian curvature caused by wavy graphite layers and high concentration defects are the main reason for the ferromagnetism of HCNSs.
In order to study the origin of ferromagnetism of spherical carbon structure, we prepared two kinds of hydrogenated carbon nanospheres(HCNSs) by solvothermal synthesis at 80 and 120℃, respectively, using Na as reducing agent and chloroform as raw material. Then we performed systematic characterization on them. According to SEM images, we found that the average particle size of HCNSs synthesized at 80℃ was 150 nm, while the average particle size of HCNSs synthesized at 120℃ was 300 nm, and the dispersion of the latter is better than that of the former. The TEM images showed that both hydrogenated carbon nanospheres were in the form of onion-like graphite, and the graphite layer was distributed in a wave shape on the curved surface of the carbon sphere. It can be seen from the X-ray photoelectron spectroscopy that the degree of hydrogenation of the hydrogenated carbon nanospheres at 80℃ is higher, which is consistent with the results of elemental analysis. The infrared spectroscopy (IR) of the HCNSs indicates that the two nanospheres have relative low carbon-hydrogen bond content. The Raman spectra of the HCNSs indicates that the obtained HCNSs have high degree of disorder and poor crystallinity. We magnetically characterized the HCNSs at room temperature, and the results show that both the HCNSs have ferromagnetism. The negative Gaussian curvature caused by wavy graphite layers and high concentration defects are the main reason for the ferromagnetism of HCNSs.
2019, 35(7): 1195-1202
doi: 10.11862/CJIC.2019.131
Abstract:
An ultra-thin MoS2/reduced graphene oxide (UT-MoS2/rGO) catalyst was prepared by one-step hydrothermal method, in which H3PO4·12MoO3 and C3H7NO2S were used as precursors and rGO was used as the carbon source. The microstructure of the UT-MoS2/rGO catalyst and its catalytic performance for hydrogen evolution reaction (HER) were studied. The results showed that UT-MoS2/rGO hybrid exhibited excellent electrocatalytic properties due to rich active sites from UT-MoS2, robust support of electrically conducting rGO and good bonding between UT-MoS2 and rGO. The initial overpotential was -66 mV; the overpotential was -145 mV at a current density of -10 mA·cm-2 with the Tafel slope of 42.9 mV·dec-1; the AC impedance was 0.76 Ω; the catalytic activity maintained 98% after 1 000 cycles at 0.1 to 0.2 V.
An ultra-thin MoS2/reduced graphene oxide (UT-MoS2/rGO) catalyst was prepared by one-step hydrothermal method, in which H3PO4·12MoO3 and C3H7NO2S were used as precursors and rGO was used as the carbon source. The microstructure of the UT-MoS2/rGO catalyst and its catalytic performance for hydrogen evolution reaction (HER) were studied. The results showed that UT-MoS2/rGO hybrid exhibited excellent electrocatalytic properties due to rich active sites from UT-MoS2, robust support of electrically conducting rGO and good bonding between UT-MoS2 and rGO. The initial overpotential was -66 mV; the overpotential was -145 mV at a current density of -10 mA·cm-2 with the Tafel slope of 42.9 mV·dec-1; the AC impedance was 0.76 Ω; the catalytic activity maintained 98% after 1 000 cycles at 0.1 to 0.2 V.
2019, 35(7): 1203-1211
doi: 10.11862/CJIC.2019.142
Abstract:
In order to solve the defects of TiO2 photocatalyst, including the rapid recombination of photo-generated electronhole pairs and low solar light utilization, two dimensional TiO2/DL-Ti3C2 composite photocatalysts were prepared using solvothermal method to control the oxidation of delaminated Ti3C2 MXene with few layers (DL-Ti3C2). The photocatalytic performance of TiO2/DL-Ti3C2 composite was evaluated by degrading rhodamine B solution. The results show that TiO2/DL-Ti3C2 photocatalyst exhibited strong absorption for visible light and better photocatalytic performance than pure DL-Ti3C2 and P25. The TiO2/DL-Ti3C2 composite oxidized at 160℃ in solvothermal process obtained the best photocatalytic performance. When the oxidation temperature was too low, the amount of TiO2 formed in the composite was insufficient to produce enough photo-generated electron-holes pairs, resulting in the unsatisfied performance of the photocatalyst. On the contrary, when the oxidation temperature was exceedingly high, the residual DL-Ti3C2 was unable to keep its outstanding conductivity, which accelerated the fast recombination of photo-generated electron-hole pairs and made the performance poor. Consequently, the relative contents of TiO2 and DL-Ti3C2 in TiO2/DL-Ti3C2 composites could be effectively regulated by varying the oxidation temperature of DL-Ti3C2, so as to improve the photocatalytic activity due to the synergistic effects of TiO2 and DL-Ti3C2.
In order to solve the defects of TiO2 photocatalyst, including the rapid recombination of photo-generated electronhole pairs and low solar light utilization, two dimensional TiO2/DL-Ti3C2 composite photocatalysts were prepared using solvothermal method to control the oxidation of delaminated Ti3C2 MXene with few layers (DL-Ti3C2). The photocatalytic performance of TiO2/DL-Ti3C2 composite was evaluated by degrading rhodamine B solution. The results show that TiO2/DL-Ti3C2 photocatalyst exhibited strong absorption for visible light and better photocatalytic performance than pure DL-Ti3C2 and P25. The TiO2/DL-Ti3C2 composite oxidized at 160℃ in solvothermal process obtained the best photocatalytic performance. When the oxidation temperature was too low, the amount of TiO2 formed in the composite was insufficient to produce enough photo-generated electron-holes pairs, resulting in the unsatisfied performance of the photocatalyst. On the contrary, when the oxidation temperature was exceedingly high, the residual DL-Ti3C2 was unable to keep its outstanding conductivity, which accelerated the fast recombination of photo-generated electron-hole pairs and made the performance poor. Consequently, the relative contents of TiO2 and DL-Ti3C2 in TiO2/DL-Ti3C2 composites could be effectively regulated by varying the oxidation temperature of DL-Ti3C2, so as to improve the photocatalytic activity due to the synergistic effects of TiO2 and DL-Ti3C2.
2019, 35(7): 1212-1220
doi: 10.11862/CJIC.2019.151
Abstract:
Two benzyltin complexes has been synthesized via the reaction of substituted benzoyl hydrazine-pyruvic acid with dibenzyltin dichloride. The complexes C1 and C2 have been characterized by IR, 1H NMR, 13C NMR 119Sn NMR spectra, elemental analysis, HRMS and the crystal structures have been determined by X-ray diffraction. Crystallographic data show that C1 forms a one-dimensional chain structure, C2 is a centrosymmetric dimer, and there is a Sn2O2 four-membered ring in the middle of the molecule. In vitro antitumor activities of both complexes were evaluated by MTT against three human cancer cell lines (H460, HepG2, MCF7). The interaction between complex C1 and calf thymus DNA were studied by EB fluorescent probe, and the ability of complex C1 to cleave plasmid DNA pBR322 was investigated by gel electrophoresis. The results show that the complexes C1 and C2 have good inhibitory effects on three kinds of cancer cells, but C1 is better than C2. The interaction of C1 with calf thymus DNA are intercalation, and it can effectively cleave DNA pBR322.
Two benzyltin complexes has been synthesized via the reaction of substituted benzoyl hydrazine-pyruvic acid with dibenzyltin dichloride. The complexes C1 and C2 have been characterized by IR, 1H NMR, 13C NMR 119Sn NMR spectra, elemental analysis, HRMS and the crystal structures have been determined by X-ray diffraction. Crystallographic data show that C1 forms a one-dimensional chain structure, C2 is a centrosymmetric dimer, and there is a Sn2O2 four-membered ring in the middle of the molecule. In vitro antitumor activities of both complexes were evaluated by MTT against three human cancer cell lines (H460, HepG2, MCF7). The interaction between complex C1 and calf thymus DNA were studied by EB fluorescent probe, and the ability of complex C1 to cleave plasmid DNA pBR322 was investigated by gel electrophoresis. The results show that the complexes C1 and C2 have good inhibitory effects on three kinds of cancer cells, but C1 is better than C2. The interaction of C1 with calf thymus DNA are intercalation, and it can effectively cleave DNA pBR322.
2019, 35(7): 1221-1229
doi: 10.11862/CJIC.2019.153
Abstract:
TiO2/CdSe heterojunction was synthesized by anodic oxidation method and electrochemical deposition method. Then dehydrated polyvinyl alcohol films were spin coated on TiO2/CdSe films with the annealing process. The crystal structure, morphology, photoelectrochemical and photocatlytic properties of the samples were investigated by XRD, SEM, FTIR, UV-Vis, PL, electrochemical and rhodamine B (RhB) degradation test. The photo-corrosion resistance of the nanocomposites were also evaluated by measuring the concentration of Cd2+ produced in the RhB degradation process. The results show that TiO2/CdSe/PVA nanocomposites possess more excellent photocatalytic activity and good stability and photo-corrosion resistant properties compared to TiO2/CdSe under visible light irradiation. Meanwhile, PVA can restrain Cd2+ the secondary pollutants in photocatalytic reaction.
TiO2/CdSe heterojunction was synthesized by anodic oxidation method and electrochemical deposition method. Then dehydrated polyvinyl alcohol films were spin coated on TiO2/CdSe films with the annealing process. The crystal structure, morphology, photoelectrochemical and photocatlytic properties of the samples were investigated by XRD, SEM, FTIR, UV-Vis, PL, electrochemical and rhodamine B (RhB) degradation test. The photo-corrosion resistance of the nanocomposites were also evaluated by measuring the concentration of Cd2+ produced in the RhB degradation process. The results show that TiO2/CdSe/PVA nanocomposites possess more excellent photocatalytic activity and good stability and photo-corrosion resistant properties compared to TiO2/CdSe under visible light irradiation. Meanwhile, PVA can restrain Cd2+ the secondary pollutants in photocatalytic reaction.
2019, 35(7): 1230-1238
doi: 10.11862/CJIC.2019.144
Abstract:
The morphologically uniform Co3O4 hexagonal plates (h-Co3O4) with the dominantly exposed (112) facet were fabricated by a hydrothermal synthesis approach. Then Cu elemental doping was successfully applied to the h-Co3O4 substrate, and further controllable deposition of Pd nanoparticles with a narrow size distribution was achievevd. All the fabrication procedures were technically simplified and environmentally friendly, with high production efficiency. Among the various catalysts, the Pd/h-Cu0.18Co2.82On showed the lowest T90 value (the reaction temperature at which the conversion rate of toluene reaches 90%) (198℃) for toluene combustion. The structural and physicochemical properties of catalysts were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), N2 adsorption-desorption (BET), hydrogen temperature programmed reduction (H2-TPR), and X-ray photoelectron spectroscopy (XPS). The results showed that the specific surface area of the substrate decreased after the Cu doping into Co3O4, accompanying with the enriched surface defects (oxygen vacant sites) responsible for the enhanced capability of oxygen adsorption/activation and the abundant oxygen adspecies as a result. These characters ensured a promising catalyst performance comparable to that of noble metal-based catalysts. The surface dispersed Pd component was found to mainly exist in the form of PdO, and the Cu-doping of substrate further increased the oxidation state of Pd species, accounting for the existence of highly reactive oxygen species in a greater amount.
The morphologically uniform Co3O4 hexagonal plates (h-Co3O4) with the dominantly exposed (112) facet were fabricated by a hydrothermal synthesis approach. Then Cu elemental doping was successfully applied to the h-Co3O4 substrate, and further controllable deposition of Pd nanoparticles with a narrow size distribution was achievevd. All the fabrication procedures were technically simplified and environmentally friendly, with high production efficiency. Among the various catalysts, the Pd/h-Cu0.18Co2.82On showed the lowest T90 value (the reaction temperature at which the conversion rate of toluene reaches 90%) (198℃) for toluene combustion. The structural and physicochemical properties of catalysts were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), N2 adsorption-desorption (BET), hydrogen temperature programmed reduction (H2-TPR), and X-ray photoelectron spectroscopy (XPS). The results showed that the specific surface area of the substrate decreased after the Cu doping into Co3O4, accompanying with the enriched surface defects (oxygen vacant sites) responsible for the enhanced capability of oxygen adsorption/activation and the abundant oxygen adspecies as a result. These characters ensured a promising catalyst performance comparable to that of noble metal-based catalysts. The surface dispersed Pd component was found to mainly exist in the form of PdO, and the Cu-doping of substrate further increased the oxidation state of Pd species, accounting for the existence of highly reactive oxygen species in a greater amount.
2019, 35(7): 1239-1247
doi: 10.11862/CJIC.2019.159
Abstract:
Au nanoparticles supported on layered double hydroxides (Au/LDHs) and AuCu alloy nanoparticles supported on layered double hydroxides (AuCu/LDHs) based on ZnAl layered double hydroxides (ZnAl-LDHs) were synthesized and used for catalyzing water gas shift reaction (WGSR). The structure and composition of Au/LDHs and AuCu/LDHs was characterized and confirmed by using X-ray powder diffraction (XRD), high resolution transmission electron microscopy (HRTEM) and scanning and transmission electron microscope (STEM). The effect of different molar ratios of Au and Cu (nAu:nCu) for AuCu/LDHs onto the catalytic performance of WGSR was investigated and compared with the activity from Au/LDHs. It indicates that Au/LDHs has obviously higher activity compared to plain LDHs, while, AuCu alloy supporting can further largely enhance the catalytic activity for WGSR. Au2Cu1/LDHs (nAu:nCu=2:1) exhibited the best catalytic efficiency:activity was 207.1 μmol·gcat-1·s-1, TOF was 1.79 s-1, and activity energy was 31.1 kJ·mol-1. The effect of nAu:nCu onto the Au particle size, Au dispersity, coverage degree of Au, and catalytic activity was discussed based on the comparison of physicochemical properties for different catalysts. The active species of Au/LDHs and AuCu/LDHs with different nAu:nCu were analyzed and compared by X-ray photoelectron spectrometry (XPS). It was found that the introduction of the secondary element increased the percentage of Auδ+ (Au2Cu1/LDHs had the highest Auδ+ content), which maybe resulted in the enhancement of WGSR activity.
Au nanoparticles supported on layered double hydroxides (Au/LDHs) and AuCu alloy nanoparticles supported on layered double hydroxides (AuCu/LDHs) based on ZnAl layered double hydroxides (ZnAl-LDHs) were synthesized and used for catalyzing water gas shift reaction (WGSR). The structure and composition of Au/LDHs and AuCu/LDHs was characterized and confirmed by using X-ray powder diffraction (XRD), high resolution transmission electron microscopy (HRTEM) and scanning and transmission electron microscope (STEM). The effect of different molar ratios of Au and Cu (nAu:nCu) for AuCu/LDHs onto the catalytic performance of WGSR was investigated and compared with the activity from Au/LDHs. It indicates that Au/LDHs has obviously higher activity compared to plain LDHs, while, AuCu alloy supporting can further largely enhance the catalytic activity for WGSR. Au2Cu1/LDHs (nAu:nCu=2:1) exhibited the best catalytic efficiency:activity was 207.1 μmol·gcat-1·s-1, TOF was 1.79 s-1, and activity energy was 31.1 kJ·mol-1. The effect of nAu:nCu onto the Au particle size, Au dispersity, coverage degree of Au, and catalytic activity was discussed based on the comparison of physicochemical properties for different catalysts. The active species of Au/LDHs and AuCu/LDHs with different nAu:nCu were analyzed and compared by X-ray photoelectron spectrometry (XPS). It was found that the introduction of the secondary element increased the percentage of Auδ+ (Au2Cu1/LDHs had the highest Auδ+ content), which maybe resulted in the enhancement of WGSR activity.
