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2023 Volume 39 Issue 11
2023, 39(11): 2033-2041
doi: 10.11862/CJIC.2023.171
Abstract:
Nanoscale hafnium-containing metal-organic frameworks (Hf-nMOFs) with octahedral (Hf-MOFs-1) and sheet-like (Hf-MOFs-2) structures were synthesized by a solvothermal method using hafnium clusters as the connection point of the MOF, rigid dicarboxylic ligand 2, 2'-bipyridyl-5, 5'-dicarboxylic acid as the connector, acetic acid or trifluoroacetic acid and water as the structural regulator. Subsequently, a post-modification method was used to incorporate Fe3+ into the backbone of Hf-nMOFs, leading to the creation of multifunctional nMOFs, designated as Hf-Fe-MOFs-1 and Hf-Fe-MOFs-2. In a mimic tumor microenvironment, the detection of hydroxyl radicals showed that X-ray irradiation significantly increased the generation efficiency of hydroxyl radicals in both Hf-Fe-MOFs-1 and Hf-Fe-MOFs-2, with a more generation ability of sheet-like Hf-Fe-MOFs-2 than that of octahedral Hf-Fe-MOFs-1. Additionally, cellular assays demonstrated successful uptake of the Hf-nMOFs by cells and confirmed their efficacy in achieving low-dose X-ray-promoted chemodynamic synergistic therapy.
Nanoscale hafnium-containing metal-organic frameworks (Hf-nMOFs) with octahedral (Hf-MOFs-1) and sheet-like (Hf-MOFs-2) structures were synthesized by a solvothermal method using hafnium clusters as the connection point of the MOF, rigid dicarboxylic ligand 2, 2'-bipyridyl-5, 5'-dicarboxylic acid as the connector, acetic acid or trifluoroacetic acid and water as the structural regulator. Subsequently, a post-modification method was used to incorporate Fe3+ into the backbone of Hf-nMOFs, leading to the creation of multifunctional nMOFs, designated as Hf-Fe-MOFs-1 and Hf-Fe-MOFs-2. In a mimic tumor microenvironment, the detection of hydroxyl radicals showed that X-ray irradiation significantly increased the generation efficiency of hydroxyl radicals in both Hf-Fe-MOFs-1 and Hf-Fe-MOFs-2, with a more generation ability of sheet-like Hf-Fe-MOFs-2 than that of octahedral Hf-Fe-MOFs-1. Additionally, cellular assays demonstrated successful uptake of the Hf-nMOFs by cells and confirmed their efficacy in achieving low-dose X-ray-promoted chemodynamic synergistic therapy.
2023, 39(11): 2042-2054
doi: 10.11862/CJIC.2023.183
Abstract:
ZSM-5 zeolites with low silica-to-alumina ratios were hydrothermally synthesized by adding NH4+ cation and using ammonia as mineralizer. The effects of Si source, Al source, mineralizer, and cation on the physiochemical properties of the prepared ZSM-5 zeolites were investigated. The crystallinity, crystal size, and silica-to-alumina ratio of zeolites were examined using X-ray diffraction (XRD), scanning electron microscopy (SEM), solid state nuclear magnetic resonance (MAS-NMR), etc. The effect of silica-to-alumina ratio on the catalytic cracking of n-heptane was also studied. The results demonstrate that the lower the silica-to-alumina ratio feeding, the harder it is for Al atoms to insert into zeolite framework. Hydrogen-form ZSM-5 zeolites with low framework silica-to-alumina ratios could be synthesized with ammonia as mineralizer and tetraethyl orthosilicate as Si source. The addition of NH4+ cation enhanced the insertion of Al atom and the framework silica-to-alumina ratio of ZSM-5 further decreased to 24.2. The results of n-heptane cracking showed that the conversion of n-heptane was improved with decreasing the framework silica-to-alumina ratio of ZSM-5 zeolites, however, the selectivity of light olefins was decreased.
ZSM-5 zeolites with low silica-to-alumina ratios were hydrothermally synthesized by adding NH4+ cation and using ammonia as mineralizer. The effects of Si source, Al source, mineralizer, and cation on the physiochemical properties of the prepared ZSM-5 zeolites were investigated. The crystallinity, crystal size, and silica-to-alumina ratio of zeolites were examined using X-ray diffraction (XRD), scanning electron microscopy (SEM), solid state nuclear magnetic resonance (MAS-NMR), etc. The effect of silica-to-alumina ratio on the catalytic cracking of n-heptane was also studied. The results demonstrate that the lower the silica-to-alumina ratio feeding, the harder it is for Al atoms to insert into zeolite framework. Hydrogen-form ZSM-5 zeolites with low framework silica-to-alumina ratios could be synthesized with ammonia as mineralizer and tetraethyl orthosilicate as Si source. The addition of NH4+ cation enhanced the insertion of Al atom and the framework silica-to-alumina ratio of ZSM-5 further decreased to 24.2. The results of n-heptane cracking showed that the conversion of n-heptane was improved with decreasing the framework silica-to-alumina ratio of ZSM-5 zeolites, however, the selectivity of light olefins was decreased.
2023, 39(11): 2055-2064
doi: 10.11862/CJIC.2023.166
Abstract:
The functionalized polymer microspheres were prepared by soap-free emulsion polymerization using potassium persulfate (KPS) as the initiator, glycidyl methacrylate (GMA) and styrene (St) as monomers. It was found that microspheres prepared by adding a trace amount of NaCl could be swelled by tetrahydrofuran (THF) to obtain monodisperse hollow microspheres with complete surfaces. The Eu(Ⅲ) complex dye was then loaded into the microspheres shell by means of organic swelling, and immunochromatographic detection of α1 microglobulin (α1-MG) and β2 microglobulin (β2-MG) was performed.
The functionalized polymer microspheres were prepared by soap-free emulsion polymerization using potassium persulfate (KPS) as the initiator, glycidyl methacrylate (GMA) and styrene (St) as monomers. It was found that microspheres prepared by adding a trace amount of NaCl could be swelled by tetrahydrofuran (THF) to obtain monodisperse hollow microspheres with complete surfaces. The Eu(Ⅲ) complex dye was then loaded into the microspheres shell by means of organic swelling, and immunochromatographic detection of α1 microglobulin (α1-MG) and β2 microglobulin (β2-MG) was performed.
2023, 39(11): 2065-2073
doi: 10.11862/CJIC.2023.180
Abstract:
The introduction of mesopores and downsizing of the crystals of SAPO-34 can enhance its diffusion efficiency, leading to high catalytic activity in methanol-to-olefin (MTO) reactions. Amphiphilic single-quaternary-ammonium molecules with different lengths of carbon chains ([N+(CH2CH3)3-CnH2n+1] [Br-], Cn-1N (n=4, 6, 8)) were designed and synthesized as co-structure directing agents. Due to the electrostatic interaction, amphiphilic molecules acted as crystal growth inhibitors or pore-forming agents, which resulted in the formation of hierarchical SAPO-34 (HS) zeolite with a smaller crystal size. When the carbon chain length was four (C4-1N), the hierarchical SAPO-34 zeolite (HS-4) was synthesized with a smaller crystal size and without other crystal phases. SAPO-34 zeolites with high mesopore volume (HS-6 and HS-8) were synthesized with C6-1N and C8-1N as co-structure directing agents. Without adding a co-structure directing agent, conventional SAPO-34 (CS) was synthesized. There were many tetrahedral particles in CS, which is the early morphology of the cubic particles. The results of the X-ray fluorescence spectrometer (XRF) and 29Si magic angle spinning nuclear magnetic resonance (29Si MAS NMR) indicated that Cn-1N molecules restrain Si atoms from incorporating into the AlPO4 framework. The results of NH3-temperature-programmed desorption (NH3-TPD) proved the strong acid gradually decreases in the order of CS > HS-8 > HS-6 > HS-4. The diffusion behaviors of methanol molecules in HS-4, HS-6, and HS-8 were better than in CS. HS-4 showed excellent catalytic performance in MTO reaction: the selectivity of ethylene (C2H4) and propylene (C3H6) (84.4%) has improved by about 4% compared to that of CS (80.5%), and the catalyst lifetime of HS-4 was about two times the lifetime of CS. HS-6 also exhibited high selectivity of C2H4 and C3H6 (83.5%), and its lifetime was almost the same as HS-4. HS-8 had a high mesopore volume, but the higher strong acidity promoted hydrogen transfer reactions, leading to alkanes, aromatics, and coke, so the lifetime of HS-8 in MTO reaction was slightly prolonged.
The introduction of mesopores and downsizing of the crystals of SAPO-34 can enhance its diffusion efficiency, leading to high catalytic activity in methanol-to-olefin (MTO) reactions. Amphiphilic single-quaternary-ammonium molecules with different lengths of carbon chains ([N+(CH2CH3)3-CnH2n+1] [Br-], Cn-1N (n=4, 6, 8)) were designed and synthesized as co-structure directing agents. Due to the electrostatic interaction, amphiphilic molecules acted as crystal growth inhibitors or pore-forming agents, which resulted in the formation of hierarchical SAPO-34 (HS) zeolite with a smaller crystal size. When the carbon chain length was four (C4-1N), the hierarchical SAPO-34 zeolite (HS-4) was synthesized with a smaller crystal size and without other crystal phases. SAPO-34 zeolites with high mesopore volume (HS-6 and HS-8) were synthesized with C6-1N and C8-1N as co-structure directing agents. Without adding a co-structure directing agent, conventional SAPO-34 (CS) was synthesized. There were many tetrahedral particles in CS, which is the early morphology of the cubic particles. The results of the X-ray fluorescence spectrometer (XRF) and 29Si magic angle spinning nuclear magnetic resonance (29Si MAS NMR) indicated that Cn-1N molecules restrain Si atoms from incorporating into the AlPO4 framework. The results of NH3-temperature-programmed desorption (NH3-TPD) proved the strong acid gradually decreases in the order of CS > HS-8 > HS-6 > HS-4. The diffusion behaviors of methanol molecules in HS-4, HS-6, and HS-8 were better than in CS. HS-4 showed excellent catalytic performance in MTO reaction: the selectivity of ethylene (C2H4) and propylene (C3H6) (84.4%) has improved by about 4% compared to that of CS (80.5%), and the catalyst lifetime of HS-4 was about two times the lifetime of CS. HS-6 also exhibited high selectivity of C2H4 and C3H6 (83.5%), and its lifetime was almost the same as HS-4. HS-8 had a high mesopore volume, but the higher strong acidity promoted hydrogen transfer reactions, leading to alkanes, aromatics, and coke, so the lifetime of HS-8 in MTO reaction was slightly prolonged.
2023, 39(11): 2074-2082
doi: 10.11862/CJIC.2023.185
Abstract:
We prepared an intermetallic PtBi nanoplate with high CO tolerance by thermal injection. The prepared intermetallic PtBi nanoplates showed excellent catalytic performance and stability for methanol oxidation reaction (MOR). The peak mass activity was up to 4.09 A·mgPt-1, which was nearly 3.2 times that of commercial Pt/C. After the current-time (I-t) stability test, the property decreased by only 5.7%, much lower than commercial Pt/C. CO-Stripping curves and evolution of cyclic voltammetric (CV-Evolution) curves confirmed high CO tolerance of inter-metallic PtBi nanoplates.
We prepared an intermetallic PtBi nanoplate with high CO tolerance by thermal injection. The prepared intermetallic PtBi nanoplates showed excellent catalytic performance and stability for methanol oxidation reaction (MOR). The peak mass activity was up to 4.09 A·mgPt-1, which was nearly 3.2 times that of commercial Pt/C. After the current-time (I-t) stability test, the property decreased by only 5.7%, much lower than commercial Pt/C. CO-Stripping curves and evolution of cyclic voltammetric (CV-Evolution) curves confirmed high CO tolerance of inter-metallic PtBi nanoplates.
2023, 39(11): 2083-2090
doi: 10.11862/CJIC.2023.182
Abstract:
Two benzohydroxamic acid organotin complexes[(o-Cl-C6H4CH2)2Sn(C6H5CONO)2] (1) and[(o-CH3-C6H4CH2)2Sn(C6H5CONO) (C6H5COO)] (2) were synthesized by solvothermal method using methanol as a solvent. Complexes 1 and 2 were characterized by elemental analysis, IR, 1H NMR, thermogravimetric analysis, single-crystal X-ray diffraction, etc. The study on the complexes has been performed with quantum chemistry calculation and in vitro anticancer activity. The results show that the two complexes are monotin nuclear structures; complexes 1 and 2 are the six-coordinated distorted octahedron configuration and seven-coordinated distorted triangular bipyramid configuration, respectively. Complex 1 showed stronger inhibitory activity on human cervical cancer cells (HeLa), hepatoma cells (HuH-7), and lung adenocarcinoma cells (H1975) than cisplatin, while complex 2 showed much weaker inhibitory activity.
Two benzohydroxamic acid organotin complexes[(o-Cl-C6H4CH2)2Sn(C6H5CONO)2] (1) and[(o-CH3-C6H4CH2)2Sn(C6H5CONO) (C6H5COO)] (2) were synthesized by solvothermal method using methanol as a solvent. Complexes 1 and 2 were characterized by elemental analysis, IR, 1H NMR, thermogravimetric analysis, single-crystal X-ray diffraction, etc. The study on the complexes has been performed with quantum chemistry calculation and in vitro anticancer activity. The results show that the two complexes are monotin nuclear structures; complexes 1 and 2 are the six-coordinated distorted octahedron configuration and seven-coordinated distorted triangular bipyramid configuration, respectively. Complex 1 showed stronger inhibitory activity on human cervical cancer cells (HeLa), hepatoma cells (HuH-7), and lung adenocarcinoma cells (H1975) than cisplatin, while complex 2 showed much weaker inhibitory activity.
2023, 39(11): 2091-2102
doi: 10.11862/CJIC.2023.174
Abstract:
A series of nitrogen-doped graphene-coated Ru-based catalysts (Ru@G-CS) were prepared using glucose, melamine, and RuCl3 as raw materials in a facile one-step pyrolysis method at 700℃ with a varied mass ratio of glucose/melamine in feed. The composition, structure, and surface morphology of these catalysts were characterized with powder X-ray diffraction, Raman spectroscopy, N2 adsorption-desorption, X-ray photoelectron spectroscopy, scanning electron microscope, and transmission electron microscope. Characterization results showed that nitrogen in the graphene skeleton can promote the dispersion of Ru, and there was also a strong interaction between nitrogen and loaded Ru. Ru@G-CS(1:4) catalyst (with the mass ratio of glucose/melamine in feed was 1:4) possesses the highest surface area (429 m2·g-1), biggest pore volume (0.45 cm3·g-1) and highly dispersed Ru particles (about 1 nm) that encapsulated in 1-2 layered graphene film. At the same time, the detected wRu0/wRu4 + (73.6/26.4), ID/IG (1.30) and I2D/IG (0.32) reached their maximum in Ru@G-CS(1:4). These catalysts were tested in dimethyl terephthalate (DMT) hydrogenation to 1,4-cyclohexane dimethyl dicarboxylate (DMCD) under mild conditions and compared with those traditional carriers (HZSM-5, Al2O3, MgO, ZnO) supported Ru catalysts. Ru@G-CS(1:4) exhibited high activity and stability at 160℃, 2.5 MPa H2, mDMT/mRu=833, the detected conversion of DMT reached 100% and the selectivity of DMCD remained higher than 98.5% within 4 h. The calculated turnover frequency of each Ru was 233.4 h-1. More importantly, Ru@G-CS(1:4) could maintain its performance at least in 10 cycles. It was concluded that the electron-structure synergistic effect might be the main reason for the excellent activity and stability of Ru@G-CS(1:4).
A series of nitrogen-doped graphene-coated Ru-based catalysts (Ru@G-CS) were prepared using glucose, melamine, and RuCl3 as raw materials in a facile one-step pyrolysis method at 700℃ with a varied mass ratio of glucose/melamine in feed. The composition, structure, and surface morphology of these catalysts were characterized with powder X-ray diffraction, Raman spectroscopy, N2 adsorption-desorption, X-ray photoelectron spectroscopy, scanning electron microscope, and transmission electron microscope. Characterization results showed that nitrogen in the graphene skeleton can promote the dispersion of Ru, and there was also a strong interaction between nitrogen and loaded Ru. Ru@G-CS(1:4) catalyst (with the mass ratio of glucose/melamine in feed was 1:4) possesses the highest surface area (429 m2·g-1), biggest pore volume (0.45 cm3·g-1) and highly dispersed Ru particles (about 1 nm) that encapsulated in 1-2 layered graphene film. At the same time, the detected wRu0/wRu4 + (73.6/26.4), ID/IG (1.30) and I2D/IG (0.32) reached their maximum in Ru@G-CS(1:4). These catalysts were tested in dimethyl terephthalate (DMT) hydrogenation to 1,4-cyclohexane dimethyl dicarboxylate (DMCD) under mild conditions and compared with those traditional carriers (HZSM-5, Al2O3, MgO, ZnO) supported Ru catalysts. Ru@G-CS(1:4) exhibited high activity and stability at 160℃, 2.5 MPa H2, mDMT/mRu=833, the detected conversion of DMT reached 100% and the selectivity of DMCD remained higher than 98.5% within 4 h. The calculated turnover frequency of each Ru was 233.4 h-1. More importantly, Ru@G-CS(1:4) could maintain its performance at least in 10 cycles. It was concluded that the electron-structure synergistic effect might be the main reason for the excellent activity and stability of Ru@G-CS(1:4).
2023, 39(11): 2103-2112
doi: 10.11862/CJIC.2023.172
Abstract:
Cu, N co-doped TiO2 nanotubes (Cu/N-TNT) were prepared by alkaline hydrothermal-ion exchange method, and the photocatalytic properties for glycerol reforming to syngas (H2 and CO) were studied. The results show that Cu/N-TNT catalyst has tubular structures with abundant oxygen vacancies (OV). N forms the impurity energy level by substituting the partial O in the form of Ti-N. Cu is doped into the crystal lattice gap and surface of the catalyst in the form of Cu2+. Cu, N co-doping promotes the effective surface charge separation on the TiO2, and improves the photocatalytic activity and selectivity for glycerol reforming to syngas. CO and H2 yields were 7.3 and 8.5 mmol· g-1 on Cu/N-TNT catalyst doped with 0.15% Cu, which were 9.1 and 70.8 times those on the original TiO2. The molar ratio of H2/CO was increased from 0.52 to 1.18, and the molar ratio of CO/CO2 was raised from 0.21 to 0.42 after 8 h of UV irradiation. N and OV on Cu/N-TNT surface provide the active sites for the decarbonylation of aldehydes and dehydration of formic acid to produce CO. Cu acts as the shallow potential traps to inhibit the electron-hole recombination. Photogenerated holes (h+) play vital roles on the syngas generation during the photocatalytic reforming of glycerol, and excessive hydroxyl radical (·OH) and superoxide radical (·O2-) favor the deep oxidation of glycerol and decrease the selectivity of CO.
Cu, N co-doped TiO2 nanotubes (Cu/N-TNT) were prepared by alkaline hydrothermal-ion exchange method, and the photocatalytic properties for glycerol reforming to syngas (H2 and CO) were studied. The results show that Cu/N-TNT catalyst has tubular structures with abundant oxygen vacancies (OV). N forms the impurity energy level by substituting the partial O in the form of Ti-N. Cu is doped into the crystal lattice gap and surface of the catalyst in the form of Cu2+. Cu, N co-doping promotes the effective surface charge separation on the TiO2, and improves the photocatalytic activity and selectivity for glycerol reforming to syngas. CO and H2 yields were 7.3 and 8.5 mmol· g-1 on Cu/N-TNT catalyst doped with 0.15% Cu, which were 9.1 and 70.8 times those on the original TiO2. The molar ratio of H2/CO was increased from 0.52 to 1.18, and the molar ratio of CO/CO2 was raised from 0.21 to 0.42 after 8 h of UV irradiation. N and OV on Cu/N-TNT surface provide the active sites for the decarbonylation of aldehydes and dehydration of formic acid to produce CO. Cu acts as the shallow potential traps to inhibit the electron-hole recombination. Photogenerated holes (h+) play vital roles on the syngas generation during the photocatalytic reforming of glycerol, and excessive hydroxyl radical (·OH) and superoxide radical (·O2-) favor the deep oxidation of glycerol and decrease the selectivity of CO.
2023, 39(11): 2113-2120
doi: 10.11862/CJIC.2023.168
Abstract:
A novel and rare case of Keggin-type polyoxometalate-based metal-organic framework compound was synthesized by solvothermal method, namely[Cu4(3, 5-datrz)4] [PW9ⅥW3ⅤO39]·H2O (1) (3, 5-datrz=3, 5-diamino-1, 2, 4-triazole). Compound 1 was characterized by single-crystal X-ray diffraction, Fourier transform infrared spectroscopy, Thermogravimetric analysis, powder X-ray diffraction, and elemental analysis. The single-crystal X-ray diffraction analysis reveals that compound 1 crystallizes in the monoclinic system with space group C2/c. The asymmetric unit contains two Cu+ ions, two 3, 5-datrz ligands, one-half of Keggin-type phosphotungstic acid anions, and one water molecule. Except for lattice water, the components are linked by covalent bonding to form Keggin-type polyoxometa-late-based metal-organic framework compounds. Compound 1 was used as a heterogeneous catalyst to catalyze the oxidation of iodine ions by H2O2 at a temperature of 55℃, and the study showed that the variation of iodine generation by compound 1 was 6.11×10-7 mol·L-1·s-1, and the conversion rate could still reach as high as 99.6% when it was reused six times.
A novel and rare case of Keggin-type polyoxometalate-based metal-organic framework compound was synthesized by solvothermal method, namely[Cu4(3, 5-datrz)4] [PW9ⅥW3ⅤO39]·H2O (1) (3, 5-datrz=3, 5-diamino-1, 2, 4-triazole). Compound 1 was characterized by single-crystal X-ray diffraction, Fourier transform infrared spectroscopy, Thermogravimetric analysis, powder X-ray diffraction, and elemental analysis. The single-crystal X-ray diffraction analysis reveals that compound 1 crystallizes in the monoclinic system with space group C2/c. The asymmetric unit contains two Cu+ ions, two 3, 5-datrz ligands, one-half of Keggin-type phosphotungstic acid anions, and one water molecule. Except for lattice water, the components are linked by covalent bonding to form Keggin-type polyoxometa-late-based metal-organic framework compounds. Compound 1 was used as a heterogeneous catalyst to catalyze the oxidation of iodine ions by H2O2 at a temperature of 55℃, and the study showed that the variation of iodine generation by compound 1 was 6.11×10-7 mol·L-1·s-1, and the conversion rate could still reach as high as 99.6% when it was reused six times.
2023, 39(11): 2121-2130
doi: 10.11862/CJIC.2023.175
Abstract:
The fabrication of the BiOBr/g-C3N4 S-scheme heterojunction is an effective way to improve photocatalytic activity. Yet, its photocatalytic activity is expected to further improve, and its photo-Fenton catalytic activity for pollutant degradation in the absence of H2O2 has not been investigated up to now. In this work, a BiOBr/g-C3N4 S-scheme heterojunction photocatalyst was successfully prepared by a calcination-ultrasonic mixing method. Herein, its photo-self-Fenton catalytic activity was investigated for the first time in the absence of H2O2. The physical properties of the samples were characterized by X-ray polycrystalline powder diffractometer (XRD), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS). Photocatalytic and photo-self-Fenton catalytic degradation of rhodamine B (RhB) were studied over BiOBr/g-C3N4 S-scheme heterojunction without/with Fe3+ in the absence of H2O2, respectively. The main active species in the photo-self-Fenton catalytic reaction were determined by capturing experiments, and the degradation mechanism of the photo-self-Fenton catalysis was proposed. The results showed that H2O2 could be formed in situ over the BiOBr/g-C3N4 S-scheme heterojunction under visible-light irradiation. The photogenerated current and the separation efficiency of photo-generated carriers can be greatly improved in the presence of Fe3+ over BiOBr/g-C3N4 S-scheme heterojunction, resulting in the enhancement of photocatalytic efficiency for RhB degradation in the photo-self-Fenton process than in the photocatalytic reaction without Fe3+. The reaction rate constant of photo-self-Fenton over BiOBr/g-C3N4 S-scheme heterojunction with Fe3+ was 0.208 min-1, which was about 5.3 times that of photocatalysis without Fe3+. It also showed good stability in the recycling experiment. The addition of Fe3+ promotes the separation of photogenerated charges and the activation of generated H2O2 by the Fe2+/Fe3+ redox cycle. The results of capturing experiments show that superoxide anion radicals (·O2-) and holes (h+) are found the main active species, and ·O2-plays a more important role in photo-self-Fenton catalysis.
The fabrication of the BiOBr/g-C3N4 S-scheme heterojunction is an effective way to improve photocatalytic activity. Yet, its photocatalytic activity is expected to further improve, and its photo-Fenton catalytic activity for pollutant degradation in the absence of H2O2 has not been investigated up to now. In this work, a BiOBr/g-C3N4 S-scheme heterojunction photocatalyst was successfully prepared by a calcination-ultrasonic mixing method. Herein, its photo-self-Fenton catalytic activity was investigated for the first time in the absence of H2O2. The physical properties of the samples were characterized by X-ray polycrystalline powder diffractometer (XRD), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS). Photocatalytic and photo-self-Fenton catalytic degradation of rhodamine B (RhB) were studied over BiOBr/g-C3N4 S-scheme heterojunction without/with Fe3+ in the absence of H2O2, respectively. The main active species in the photo-self-Fenton catalytic reaction were determined by capturing experiments, and the degradation mechanism of the photo-self-Fenton catalysis was proposed. The results showed that H2O2 could be formed in situ over the BiOBr/g-C3N4 S-scheme heterojunction under visible-light irradiation. The photogenerated current and the separation efficiency of photo-generated carriers can be greatly improved in the presence of Fe3+ over BiOBr/g-C3N4 S-scheme heterojunction, resulting in the enhancement of photocatalytic efficiency for RhB degradation in the photo-self-Fenton process than in the photocatalytic reaction without Fe3+. The reaction rate constant of photo-self-Fenton over BiOBr/g-C3N4 S-scheme heterojunction with Fe3+ was 0.208 min-1, which was about 5.3 times that of photocatalysis without Fe3+. It also showed good stability in the recycling experiment. The addition of Fe3+ promotes the separation of photogenerated charges and the activation of generated H2O2 by the Fe2+/Fe3+ redox cycle. The results of capturing experiments show that superoxide anion radicals (·O2-) and holes (h+) are found the main active species, and ·O2-plays a more important role in photo-self-Fenton catalysis.
2023, 39(11): 2131-2142
doi: 10.11862/CJIC.2023.170
Abstract:
The lithium-rich manganese-based material (Li1.2Ni0.13Co0.13Mn0.54O2, LNCM) is susceptible to structural transformations and interfacial side reactions during charge and discharge, leading to rapid capacity decay and posing significant challenges for its commercial application. In this study, a synergistic modification strategy involving PO43- (P) doping and AlF3 coating was employed to prepare the P-LNCM@AlF3 cathode material, which enhances the structural stability of LNCM and suppresses interfacial side reactions. Among them, the large tetrahedral PO43- polyanion doping in the lattice can inhibit the migration of transition metal ions and reduce the volume change due to its stronger bonding with transition metal ions compared to oxygen, thus stabilizing the crystal structure. Moreover, the PO43- doping can expand the lithium layer spacing and promote the diffusion of Li+, thus enhancing the multiplicative performance of the material. In addition, the AlF3 nanolayer coating on the surface of the active material reduces its contact with the electrolyte, which can inhibit the side reaction between the material and the electrolyte and thus enhance the interfacial stability. Based on these advantages, the P-LNCM@AlF3 cathode exhibited excellent electrochemical performance. It exhibited a discharge specific capacity of 179.2 mAh·g-1 at a current density of 1C and 161.5 mAh·g-1 after 200 cycles, with a capacity retention rate of 90.12%. Even at a high current density of 5C, a discharge capacity of 128.8 mAh·g-1 could be achieved.
The lithium-rich manganese-based material (Li1.2Ni0.13Co0.13Mn0.54O2, LNCM) is susceptible to structural transformations and interfacial side reactions during charge and discharge, leading to rapid capacity decay and posing significant challenges for its commercial application. In this study, a synergistic modification strategy involving PO43- (P) doping and AlF3 coating was employed to prepare the P-LNCM@AlF3 cathode material, which enhances the structural stability of LNCM and suppresses interfacial side reactions. Among them, the large tetrahedral PO43- polyanion doping in the lattice can inhibit the migration of transition metal ions and reduce the volume change due to its stronger bonding with transition metal ions compared to oxygen, thus stabilizing the crystal structure. Moreover, the PO43- doping can expand the lithium layer spacing and promote the diffusion of Li+, thus enhancing the multiplicative performance of the material. In addition, the AlF3 nanolayer coating on the surface of the active material reduces its contact with the electrolyte, which can inhibit the side reaction between the material and the electrolyte and thus enhance the interfacial stability. Based on these advantages, the P-LNCM@AlF3 cathode exhibited excellent electrochemical performance. It exhibited a discharge specific capacity of 179.2 mAh·g-1 at a current density of 1C and 161.5 mAh·g-1 after 200 cycles, with a capacity retention rate of 90.12%. Even at a high current density of 5C, a discharge capacity of 128.8 mAh·g-1 could be achieved.
2023, 39(11): 2143-2150
doi: 10.11862/CJIC.2023.178
Abstract:
An erythrocyte-like copper sulfide material with twins was synthesized by a solvothermal method. It was found that the different precursor proportions and reaction times play key roles in the formation of erythrocyte-like CuS. The formation mechanism of twin erythrocyte-like CuS was systematically elaborated. The Fenton-like system composed of CuS and H2O2 showed excellent degradation performance under visible light irradiation, and the degradation rate of methylene blue reached 95% after 50 min under visible light. The catalytic performance of the erythrocyte-like CuS and the synthetic flower ball-like CuS was compared, and the degradation performance of the erythrocyte-like CuS was better, indicating that the twin crystals accelerate the separation of photogenerated electrons-holes.
An erythrocyte-like copper sulfide material with twins was synthesized by a solvothermal method. It was found that the different precursor proportions and reaction times play key roles in the formation of erythrocyte-like CuS. The formation mechanism of twin erythrocyte-like CuS was systematically elaborated. The Fenton-like system composed of CuS and H2O2 showed excellent degradation performance under visible light irradiation, and the degradation rate of methylene blue reached 95% after 50 min under visible light. The catalytic performance of the erythrocyte-like CuS and the synthetic flower ball-like CuS was compared, and the degradation performance of the erythrocyte-like CuS was better, indicating that the twin crystals accelerate the separation of photogenerated electrons-holes.
2023, 39(11): 2151-2159
doi: 10.11862/CJIC.2023.177
Abstract:
Electrocatalytic CO2 reduction reaction (eCO2RR) is still limited by the intrinsic activity and mass transfer of catalysts, resulting in low catalytic activity and high reaction onset potential. Herein, we explored the eCO2RR performance of zeolite imidazole framework (ZIF-8) with different sizes. We took ZIF-8 with a particle size of 50 nm as the research object, and further introduced carbon nanotubes (CNT) as the conductive substrate material. The hierarchical porous structure and hydrophobic interface of ZIF-8-50@CNT were constructed by in-situ growth. The results of eCO2RR experiment showed that the introduction of CNT improved the conductivity of the catalyst, and the optimized composite effectively reduced the onset potential of the reaction. At -1.1 V (versus reversible hydrogen electrode (RHE)), the partial CO current density of ZIF-8-50@CNT was 15.6 mA·cm-2, and the catalyst surface activity of ZIF-8-50@CNT catalyst is increased by 3.5 times that of ZIF-8-50, and the Tafel slope was reduced to 136 mV·dec-1. The selectivity and stability of the product CO were improved, and the Faraday efficiency (FE) of CO remained 80% at -0.9--1.2 V (vs RHE). In the 10 h stability test, the catalyst remained stable. The overall eCO2RR performance of catalyst was enhanced.
Electrocatalytic CO2 reduction reaction (eCO2RR) is still limited by the intrinsic activity and mass transfer of catalysts, resulting in low catalytic activity and high reaction onset potential. Herein, we explored the eCO2RR performance of zeolite imidazole framework (ZIF-8) with different sizes. We took ZIF-8 with a particle size of 50 nm as the research object, and further introduced carbon nanotubes (CNT) as the conductive substrate material. The hierarchical porous structure and hydrophobic interface of ZIF-8-50@CNT were constructed by in-situ growth. The results of eCO2RR experiment showed that the introduction of CNT improved the conductivity of the catalyst, and the optimized composite effectively reduced the onset potential of the reaction. At -1.1 V (versus reversible hydrogen electrode (RHE)), the partial CO current density of ZIF-8-50@CNT was 15.6 mA·cm-2, and the catalyst surface activity of ZIF-8-50@CNT catalyst is increased by 3.5 times that of ZIF-8-50, and the Tafel slope was reduced to 136 mV·dec-1. The selectivity and stability of the product CO were improved, and the Faraday efficiency (FE) of CO remained 80% at -0.9--1.2 V (vs RHE). In the 10 h stability test, the catalyst remained stable. The overall eCO2RR performance of catalyst was enhanced.
2023, 39(11): 2160-2168
doi: 10.11862/CJIC.2023.179
Abstract:
Cu(ClO4)2·6H2O and (1-methyl-1H-benzimidazol-2-yl) methanol (HL) reacted in a mixed solution of methanol and acetonitrile to produce dark blue[Cu(HL)3](ClO4)2·H2O (1) and light blue[Cu(HL)3](ClO4)2 (2). Their structures were characterized by elemental analysis, IR, thermogravimetric analysis (TGA), and single-crystal X-ray diffraction. The test results showed that complexes 1 and 2 are both composed of[Cu(HL)3]2+ and the counter anion ClO4-, except for the addition of one free water molecule in 1. The Cu(Ⅱ) ions in 1 and 2 are coordinated with N and O atoms from the HL; the coordination number was six. The results of TGA showed that the structures of 1 and 2 could remain unchanged in a range of 30-245℃. However, complex 1 with a dark blue color had a wider absorption peak at 289 nm compared to 2 with a light blue color. The adsorption experiment showed that 1 exhibited better adsorption performance for Cr(Ⅵ) than 2 at pH=4-8. It can be seen that the free water molecule in 1 has a certain impact on light absorption and the adsorption of Cr(Ⅵ).
Cu(ClO4)2·6H2O and (1-methyl-1H-benzimidazol-2-yl) methanol (HL) reacted in a mixed solution of methanol and acetonitrile to produce dark blue[Cu(HL)3](ClO4)2·H2O (1) and light blue[Cu(HL)3](ClO4)2 (2). Their structures were characterized by elemental analysis, IR, thermogravimetric analysis (TGA), and single-crystal X-ray diffraction. The test results showed that complexes 1 and 2 are both composed of[Cu(HL)3]2+ and the counter anion ClO4-, except for the addition of one free water molecule in 1. The Cu(Ⅱ) ions in 1 and 2 are coordinated with N and O atoms from the HL; the coordination number was six. The results of TGA showed that the structures of 1 and 2 could remain unchanged in a range of 30-245℃. However, complex 1 with a dark blue color had a wider absorption peak at 289 nm compared to 2 with a light blue color. The adsorption experiment showed that 1 exhibited better adsorption performance for Cr(Ⅵ) than 2 at pH=4-8. It can be seen that the free water molecule in 1 has a certain impact on light absorption and the adsorption of Cr(Ⅵ).
2023, 39(11): 2169-2180
doi: 10.11862/CJIC.2023.188
Abstract:
Bi3OXy(WO6)1-y (X=Cl, Br, I) solid solution materials were successfully prepared by a simple two-step hydrothermal method, which enhanced the adsorption and photocatalytic properties while changing the morphology. The structures and properties of the three composites were characterized in detail by X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet-visible diffuse reflection spectroscopy (UV-Vis DRS), X-ray photoelectron spectroscopy (XPS), and photoluminescence spectroscopy (PL). Solid solutions were speculated in principle. Compared to the BW monomer, the formation of the BI solid solution in Bi3OXy((WO6)1-y resulted in a decreased band-gap, which led to an enhanced capacity for absorbing visible light. Furthermore, it helped to reduce the recombination rate of electron-hole pairs generated by light. Bi3OXy((WO6)1-y exhibited a strong adsorption capacity for rhodamine B (RhB) cationic dye. Adsorption kinetics of different materials were investigated through adsorption experiments conducted at high concentrations.
Bi3OXy(WO6)1-y (X=Cl, Br, I) solid solution materials were successfully prepared by a simple two-step hydrothermal method, which enhanced the adsorption and photocatalytic properties while changing the morphology. The structures and properties of the three composites were characterized in detail by X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet-visible diffuse reflection spectroscopy (UV-Vis DRS), X-ray photoelectron spectroscopy (XPS), and photoluminescence spectroscopy (PL). Solid solutions were speculated in principle. Compared to the BW monomer, the formation of the BI solid solution in Bi3OXy((WO6)1-y resulted in a decreased band-gap, which led to an enhanced capacity for absorbing visible light. Furthermore, it helped to reduce the recombination rate of electron-hole pairs generated by light. Bi3OXy((WO6)1-y exhibited a strong adsorption capacity for rhodamine B (RhB) cationic dye. Adsorption kinetics of different materials were investigated through adsorption experiments conducted at high concentrations.
2023, 39(11): 2181-2187
doi: 10.11862/CJIC.2023.187
Abstract:
Four isomorphic rare earth complexes[M(Hcpna)(cpna)(H2O)3]n, where M=Dy (1), Ho (2), Er (3), Tm (4), have been synthesized by a solvothermal method based on 5-(4-carboxyphenoxy)nicotinic acid ligand (H2cpna) and rare earth metal ions Dy3+, Ho3+, Er3+, and Tm3+. Single crystal X-ray diffraction analyses reveal that complexes 1, 2, 3, and 4 are isostructural, and the structures are all 1D chain structures. The complexes were characterized by IR, elemental analysis, and powder X-ray diffraction, while the fluorescence and magnetic properties of the complexes were studied. The fluorescence test results show that the fluorescence intensity of complexes 1-4 were all lower than that of the H2cpna ligand. The magnetism of complexes 1-4 were studied in the 2-300 K range at 1 kOe dc field. The χmT values of complexes 1, 2, 3, and 4 were 14.04, 14.15, 11.08, and 6.83 cm3·mol-1·K respectively at room temperature.
Four isomorphic rare earth complexes[M(Hcpna)(cpna)(H2O)3]n, where M=Dy (1), Ho (2), Er (3), Tm (4), have been synthesized by a solvothermal method based on 5-(4-carboxyphenoxy)nicotinic acid ligand (H2cpna) and rare earth metal ions Dy3+, Ho3+, Er3+, and Tm3+. Single crystal X-ray diffraction analyses reveal that complexes 1, 2, 3, and 4 are isostructural, and the structures are all 1D chain structures. The complexes were characterized by IR, elemental analysis, and powder X-ray diffraction, while the fluorescence and magnetic properties of the complexes were studied. The fluorescence test results show that the fluorescence intensity of complexes 1-4 were all lower than that of the H2cpna ligand. The magnetism of complexes 1-4 were studied in the 2-300 K range at 1 kOe dc field. The χmT values of complexes 1, 2, 3, and 4 were 14.04, 14.15, 11.08, and 6.83 cm3·mol-1·K respectively at room temperature.
2023, 39(11): 2188-2196
doi: 10.11862/CJIC.2023.181
Abstract:
Based on the energetic ligand 4, 5-bis(tetrazol-5-yl)imidazole (H3BTI), a novel energetic coordination polymer[Co4(HBTI)4(H2O)8] (1) was prepared under hydrothermal conditions. The crystal structure measurement indicates that 1 exhibits a tetranuclear structure with the central ion Co (Ⅱ) adopting octahedral geometry. The non-isothermal kinetic parameters of 1 were determined using two different methods including Kissinger and Ozawa-Doyle. Through the density functional theory (DFT) calculation, its explosive performance was further conducted. Additionally, its friction sensitivity and impact sensitivity were larger than 360 N and 40 J, respectively. Further-more, during the combustion decomposition process, compound 1 could effectively advance the decomposition temperature of ammonium perchlorate (AP) and 1, 3, 5-trinitro-1, 3, 5-triazacyclohexane (RDX) by 25 and 11℃, respectively.
Based on the energetic ligand 4, 5-bis(tetrazol-5-yl)imidazole (H3BTI), a novel energetic coordination polymer[Co4(HBTI)4(H2O)8] (1) was prepared under hydrothermal conditions. The crystal structure measurement indicates that 1 exhibits a tetranuclear structure with the central ion Co (Ⅱ) adopting octahedral geometry. The non-isothermal kinetic parameters of 1 were determined using two different methods including Kissinger and Ozawa-Doyle. Through the density functional theory (DFT) calculation, its explosive performance was further conducted. Additionally, its friction sensitivity and impact sensitivity were larger than 360 N and 40 J, respectively. Further-more, during the combustion decomposition process, compound 1 could effectively advance the decomposition temperature of ammonium perchlorate (AP) and 1, 3, 5-trinitro-1, 3, 5-triazacyclohexane (RDX) by 25 and 11℃, respectively.
2023, 39(11): 2197-2208
doi: 10.11862/CJIC.2023.173
Abstract:
A facile precipitation transformation method at room temperature was employed to efficiently prepare the FeTrz@PB heterostructural composites containing both[Fe(Htrz)2(trz)](BF4) (Htrz=1H-1, 2, 4-triazole) and Prussian blue KFeⅢ[FeⅡ(CN)6] with the coexistence of spin crossover (SCO) and long-range magnetic ordering (LRMO). The controllable growth process of these heterostructural composites was fully characterized by scanning electron micro-scope, transmission electron microscope, powder X-ray diffraction, FTIR, X-ray photoelectron spectroscopy, energy-dispersion X-ray analysis, thermogravimetric analysis, and magnetic studies. The size of the PB particles and the appearance of FeTrz@PB can be tuned by controlling the reaction time. Increasing the reaction time leads to the increased ratio of the PB phase in the FeTrz@PB composites. Remarkably, magnetic studies on FeTrz@PB revealed the coexistence of SCO above room temperature (362-392 K) and LRMO at low temperatures (ca. 5.6 K). The high spin (HS) fraction and ZFC/FC intensity gradually increased with the growth time, while the heights of the hysteresis loops decreased gradually.
A facile precipitation transformation method at room temperature was employed to efficiently prepare the FeTrz@PB heterostructural composites containing both[Fe(Htrz)2(trz)](BF4) (Htrz=1H-1, 2, 4-triazole) and Prussian blue KFeⅢ[FeⅡ(CN)6] with the coexistence of spin crossover (SCO) and long-range magnetic ordering (LRMO). The controllable growth process of these heterostructural composites was fully characterized by scanning electron micro-scope, transmission electron microscope, powder X-ray diffraction, FTIR, X-ray photoelectron spectroscopy, energy-dispersion X-ray analysis, thermogravimetric analysis, and magnetic studies. The size of the PB particles and the appearance of FeTrz@PB can be tuned by controlling the reaction time. Increasing the reaction time leads to the increased ratio of the PB phase in the FeTrz@PB composites. Remarkably, magnetic studies on FeTrz@PB revealed the coexistence of SCO above room temperature (362-392 K) and LRMO at low temperatures (ca. 5.6 K). The high spin (HS) fraction and ZFC/FC intensity gradually increased with the growth time, while the heights of the hysteresis loops decreased gradually.
2023, 39(11): 2209-2218
doi: 10.11862/CJIC.2023.176
Abstract:
Two new 3D rare-earth molybdate frameworks, [Ln(H2O)3]3[LnMo12O42]·xH2O, where Ln=Eu (1), Tb (2); x=7 (1), 10.17 (2), have been synthesized by slow evaporation. Both of these rare earth molybdate frameworks have a new rare-earth-centered icosahedron[LnMo12O42] building unit, which is further connected to adjacent ones by {LnO9} polyhedra to form a 3D network. Photoluminescence tests reveal that 1 and 2 exhibited different emission properties, which are caused by the f-orbital energy levels of Eu3+ and Tb3+. 1 exhibited bright red emissions (CIE chromaticity coordinates: (0.66, 0.33)) corresponding to the transition from 5D0 to 7FJ (J=4, 3, 2, 1, 0), with high luminescent emission intensity and high quantum yield (about 60%). 2 exhibited light green emissions (CIE chromaticity coordinates: (0.34, 0.60)) corresponding to the transition from 5D4 to 7FJ (J=6, 5, 4, 3), with lower luminescent emission intensity and quantum yield (about 20%). Interestingly, the introduction of Tb and the presence of a large number of solvent molecules in compound 2, both lead to partial fluorescence quenching but have little effect on the fluorescence properties of 1.
Two new 3D rare-earth molybdate frameworks, [Ln(H2O)3]3[LnMo12O42]·xH2O, where Ln=Eu (1), Tb (2); x=7 (1), 10.17 (2), have been synthesized by slow evaporation. Both of these rare earth molybdate frameworks have a new rare-earth-centered icosahedron[LnMo12O42] building unit, which is further connected to adjacent ones by {LnO9} polyhedra to form a 3D network. Photoluminescence tests reveal that 1 and 2 exhibited different emission properties, which are caused by the f-orbital energy levels of Eu3+ and Tb3+. 1 exhibited bright red emissions (CIE chromaticity coordinates: (0.66, 0.33)) corresponding to the transition from 5D0 to 7FJ (J=4, 3, 2, 1, 0), with high luminescent emission intensity and high quantum yield (about 60%). 2 exhibited light green emissions (CIE chromaticity coordinates: (0.34, 0.60)) corresponding to the transition from 5D4 to 7FJ (J=6, 5, 4, 3), with lower luminescent emission intensity and quantum yield (about 20%). Interestingly, the introduction of Tb and the presence of a large number of solvent molecules in compound 2, both lead to partial fluorescence quenching but have little effect on the fluorescence properties of 1.
2023, 39(11): 2219-2230
doi: 10.11862/CJIC.2023.186
Abstract:
Under solvothermal conditions, the reaction of 2-pyridinealdoxime (HL) with NiCl2·6H2O and Zn(OAc)2· 2H2O has led to a Ni2ⅡZn2Ⅱ cluster complex with composition[Ni2Zn2(L)4Cl2(CH3O)2] (1). This complex was characterized by elemental analysis, IR spectroscopy, single-crystal X-ray diffraction, etc. The results show that 1 belongs to the orthorhombic system with the Pna21 space group. The structure of 1 contains two NiⅡ ions, two ZnⅡ ions, two Cl- ions, four L- ligands, and two CH3O- anions. The magnetic properties and photocatalytic activity toward the degradation of dyes were investigated. Magnetic susceptibility measurements at 2-300 K for the microcrystals of 1 revealed antiferromagnetic NiⅡ⋯NiⅡ interactions. 1 exhibited excellent photocatalytic capability in the degradation of methyl orange (MO) and rhodamine B (RhB) within 180 min under ultraviolet radiation. The degradation efficiencies reached 83.9% and 71.1% respectively. The mechanism of photocatalytic dye degradation was further discussed.
Under solvothermal conditions, the reaction of 2-pyridinealdoxime (HL) with NiCl2·6H2O and Zn(OAc)2· 2H2O has led to a Ni2ⅡZn2Ⅱ cluster complex with composition[Ni2Zn2(L)4Cl2(CH3O)2] (1). This complex was characterized by elemental analysis, IR spectroscopy, single-crystal X-ray diffraction, etc. The results show that 1 belongs to the orthorhombic system with the Pna21 space group. The structure of 1 contains two NiⅡ ions, two ZnⅡ ions, two Cl- ions, four L- ligands, and two CH3O- anions. The magnetic properties and photocatalytic activity toward the degradation of dyes were investigated. Magnetic susceptibility measurements at 2-300 K for the microcrystals of 1 revealed antiferromagnetic NiⅡ⋯NiⅡ interactions. 1 exhibited excellent photocatalytic capability in the degradation of methyl orange (MO) and rhodamine B (RhB) within 180 min under ultraviolet radiation. The degradation efficiencies reached 83.9% and 71.1% respectively. The mechanism of photocatalytic dye degradation was further discussed.
2023, 39(11): 2231-2239
doi: 10.11862/CJIC.2023.184
Abstract:
In this work, by the reaction of salicylaldoxime (H2Saox), isobutyric acid (HiBuac), and Ti(OiPr)4 the hexanuclear titanium oxo cluster (TOC) of[Ti6(μ3-O)4(Saox)2(iBuac)4(OiPr)8] (1) was solvothermally synthesized, and by the reaction of acetohydroxamic acid (H2Ahox), phenylphosphonic acid (PhPO3H2) and Ti(OiPr)4 the octa-nuclear TOC of[Ti8(μ3-O)2(Ahox)2(PhPO3)4(OiPr)16] (2) was prepared. Both of them were characterized by IR, elemental analyses, and single-crystal X-ray diffraction. Spectral experiments indicate that the two complexes have absorptions in the visible region. The band gaps of complexes 1 and 2 were 2.43 and 2.61 eV respectively. Complex 2 is the first H2Ahox-based TOCs that showed photocatalytic H2 evolution activity with the rate of 140.2 μmol·g-1·h-1.
In this work, by the reaction of salicylaldoxime (H2Saox), isobutyric acid (HiBuac), and Ti(OiPr)4 the hexanuclear titanium oxo cluster (TOC) of[Ti6(μ3-O)4(Saox)2(iBuac)4(OiPr)8] (1) was solvothermally synthesized, and by the reaction of acetohydroxamic acid (H2Ahox), phenylphosphonic acid (PhPO3H2) and Ti(OiPr)4 the octa-nuclear TOC of[Ti8(μ3-O)2(Ahox)2(PhPO3)4(OiPr)16] (2) was prepared. Both of them were characterized by IR, elemental analyses, and single-crystal X-ray diffraction. Spectral experiments indicate that the two complexes have absorptions in the visible region. The band gaps of complexes 1 and 2 were 2.43 and 2.61 eV respectively. Complex 2 is the first H2Ahox-based TOCs that showed photocatalytic H2 evolution activity with the rate of 140.2 μmol·g-1·h-1.
