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2020 Volume 36 Issue 8
2020, 36(8): 1413-1420
doi: 10.11862/CJIC.2020.177
Abstract:
By using F doping, a series of BiOCl nanosheets with highly exposed (001) facets were synthesized by a solvothermal-calcination route. The fabricated bare BiOCl and F doped BiOCl nanosheets were characterized by some physicochemical methods, e.g. X-ray diffraction, N2 physical absorption, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, ultraviolet-visible diffuse reflectance spectroscopy, Fourier transform infrared spectroscopy, and photoelectrochemical measurement. The results show that F doping with moderate content can promote the growth of (110) crystal plane and suppress the crystal size, inducing the for-mation of highly exposed (001) facets. Moreover, an obvious increase in surface area and surface -OH groups were obtained after F-doping. Under simulated sunlight irradiation, F doping obtained significant enhancement in the degradation of rhodamine B, and about 1.67 times increase over F1.0-BiOCl than that of bare BiOCl. Moreover, the degradation rate of F1.0-BiOCl was 1.24 times that of commercial P25(TiO2) in removal of acid orange Ⅱ. The main reasons for the increase of activity are that the exposed (001) facets induced by F-doping promoted dyes adsorption, and the separation of photo-generated electron-hole pair was also accelerated. Therefore, F-BiOCl nanosheets display superior photocatalytic performance for organic dyes degradation.
By using F doping, a series of BiOCl nanosheets with highly exposed (001) facets were synthesized by a solvothermal-calcination route. The fabricated bare BiOCl and F doped BiOCl nanosheets were characterized by some physicochemical methods, e.g. X-ray diffraction, N2 physical absorption, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, ultraviolet-visible diffuse reflectance spectroscopy, Fourier transform infrared spectroscopy, and photoelectrochemical measurement. The results show that F doping with moderate content can promote the growth of (110) crystal plane and suppress the crystal size, inducing the for-mation of highly exposed (001) facets. Moreover, an obvious increase in surface area and surface -OH groups were obtained after F-doping. Under simulated sunlight irradiation, F doping obtained significant enhancement in the degradation of rhodamine B, and about 1.67 times increase over F1.0-BiOCl than that of bare BiOCl. Moreover, the degradation rate of F1.0-BiOCl was 1.24 times that of commercial P25(TiO2) in removal of acid orange Ⅱ. The main reasons for the increase of activity are that the exposed (001) facets induced by F-doping promoted dyes adsorption, and the separation of photo-generated electron-hole pair was also accelerated. Therefore, F-BiOCl nanosheets display superior photocatalytic performance for organic dyes degradation.
2020, 36(8): 1421-1429
doi: 10.11862/CJIC.2020.141
Abstract:
The solid liquid phase equilibria and species chemical equilibrium of Mg(BO2)2 dissociated in MgCl2 aqueous solution were studied by means of Raman spectroscopy and X ray diffraction (XRD). The results indicate that the MgCl2 concentration has a great influence Mg(BO2)2 dissociation. (1) With the increasing of MgCl2 concentration from 0 to saturated state, the apparent solubility of Mg(BO2)2 increased from 0.79% to 1.96%, and pH value decreased from 9.96 to 6.27; (2) Solid species are changed gradually from Mg2B6O11·15H2O and Mg(OH)2, to Mg2B6O11·15H2O and Mg3Cl2(OH)4·4H2O; (3) Main species of polylobate anions change from B4O5(OH)42- and B3O3(OH)4- with the accounts of 49.81% and 19.54%, to B3O3(OH)4- and B5O6OH)4- with accounts of 44.57% and 40.00%, respectively.
The solid liquid phase equilibria and species chemical equilibrium of Mg(BO2)2 dissociated in MgCl2 aqueous solution were studied by means of Raman spectroscopy and X ray diffraction (XRD). The results indicate that the MgCl2 concentration has a great influence Mg(BO2)2 dissociation. (1) With the increasing of MgCl2 concentration from 0 to saturated state, the apparent solubility of Mg(BO2)2 increased from 0.79% to 1.96%, and pH value decreased from 9.96 to 6.27; (2) Solid species are changed gradually from Mg2B6O11·15H2O and Mg(OH)2, to Mg2B6O11·15H2O and Mg3Cl2(OH)4·4H2O; (3) Main species of polylobate anions change from B4O5(OH)42- and B3O3(OH)4- with the accounts of 49.81% and 19.54%, to B3O3(OH)4- and B5O6OH)4- with accounts of 44.57% and 40.00%, respectively.
2020, 36(8): 1430-1436
doi: 10.11862/CJIC.2020.154
Abstract:
A pair of homochiral coordination polymers, {[Co((R)-CBA)(1, 3-BMIB)2]·H2O}n (1-D, (R)-H2CBA=(R)-4-(1-carboxyethoxy)benzoic acid, 1, 3-BMIB=1, 3-bis(2-methyl-1H-imidazol-1-yl)benzene) and {[Co((S)-CBA)(1, 3-BMIB)2]·H2O}n (1-L), were prepared by mixing Co2+, 1, 3-BMIB and lactic acid derivates (R)-H2CBA/(S)-H2CBA under hydrothermal condition, respectively. X-ray crystallography reveals there are three types of helical chains constructed by tetra-coordinated Co(Ⅱ) centers, 1, 3-BMIB and/or CBA2- ligands in complexes 1-D and 1-L. For unsaturated Co(Ⅱ) centers can act as catalytic active site, complex 1-D with high yield was further used for photo-catalytic research. Mott-Schottky measurements indicate that complex 1-D is a typical n-type semiconductor, while the UV-Vis spectrum confirmed that complex 1-D showed strong absorption in a range of 420~650 nm. Further more, complex 1-D has the small radius and the lowest resistance in charge transportation. Finally, complex 1-D realized photocatalytic reduction of CO2 to CO with an evolution rate of 577.8 μmol·g-1·h-1 in the course of the experiment.
A pair of homochiral coordination polymers, {[Co((R)-CBA)(1, 3-BMIB)2]·H2O}n (1-D, (R)-H2CBA=(R)-4-(1-carboxyethoxy)benzoic acid, 1, 3-BMIB=1, 3-bis(2-methyl-1H-imidazol-1-yl)benzene) and {[Co((S)-CBA)(1, 3-BMIB)2]·H2O}n (1-L), were prepared by mixing Co2+, 1, 3-BMIB and lactic acid derivates (R)-H2CBA/(S)-H2CBA under hydrothermal condition, respectively. X-ray crystallography reveals there are three types of helical chains constructed by tetra-coordinated Co(Ⅱ) centers, 1, 3-BMIB and/or CBA2- ligands in complexes 1-D and 1-L. For unsaturated Co(Ⅱ) centers can act as catalytic active site, complex 1-D with high yield was further used for photo-catalytic research. Mott-Schottky measurements indicate that complex 1-D is a typical n-type semiconductor, while the UV-Vis spectrum confirmed that complex 1-D showed strong absorption in a range of 420~650 nm. Further more, complex 1-D has the small radius and the lowest resistance in charge transportation. Finally, complex 1-D realized photocatalytic reduction of CO2 to CO with an evolution rate of 577.8 μmol·g-1·h-1 in the course of the experiment.
2020, 36(8): 1437-1445
doi: 10.11862/CJIC.2020.164
Abstract:
The effects of four astragalus polysaccharides (ASP0, ASP1, ASP2 and ASP3) with carboxylic group (-COOH) content of 16.7%(w/w) but molecular weights of 11.0, 8.4, 4.7 and 2.6 kDa, respectively, on the formation of calcium oxalate (CaOx) crystals were comparatively studied. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM) results revealed that all the four ASPs inhibited COM growth, induced COD formation. The inductively coupled plasma emission spectra (ICP) revealed that these ASPs increased the concentration of soluble Ca2+ ions in the solution and reduced the amount of CaOx precipitation. Furthermore, ASPs increased the absolute value of ζ potential on the crystal surface, and thus inhibited crystal aggregation. The ability of ASPs to regulate CaOx crystal formation and induce COD formation is negatively related to its molecular weight, that is, ASP3 with the smallest molecular weight has the strongest regulatory ability. In addition, each ASPs is not only toxic to HK-2 cells, but also can repair oxalate-damaged HK-2 cells and decrease cellular ROS level, of which APS2 with moderate molecular weight showed the best repair ability.
The effects of four astragalus polysaccharides (ASP0, ASP1, ASP2 and ASP3) with carboxylic group (-COOH) content of 16.7%(w/w) but molecular weights of 11.0, 8.4, 4.7 and 2.6 kDa, respectively, on the formation of calcium oxalate (CaOx) crystals were comparatively studied. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM) results revealed that all the four ASPs inhibited COM growth, induced COD formation. The inductively coupled plasma emission spectra (ICP) revealed that these ASPs increased the concentration of soluble Ca2+ ions in the solution and reduced the amount of CaOx precipitation. Furthermore, ASPs increased the absolute value of ζ potential on the crystal surface, and thus inhibited crystal aggregation. The ability of ASPs to regulate CaOx crystal formation and induce COD formation is negatively related to its molecular weight, that is, ASP3 with the smallest molecular weight has the strongest regulatory ability. In addition, each ASPs is not only toxic to HK-2 cells, but also can repair oxalate-damaged HK-2 cells and decrease cellular ROS level, of which APS2 with moderate molecular weight showed the best repair ability.
2020, 36(8): 1446-1456
doi: 10.11862/CJIC.2020.162
Abstract:
Herein, Bi2MoO6/CoMoO4 embroidery ball structures were synthesized by a simple one-step hydrothermal method that using bismuth nitrate pentahydrate as the bismuth source. By X-ray powder diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), Fourier infrared spectroscopy (FT-IR), ultraviolet-visible diffuse reflection spectroscopy (UV-Vis DRS), fluorescence spectrum (PL), and electrochemical tests were performed to analyze the phase composition, micromorphology, optical properties, and recombination rate of photogenerated charge of the prepared catalyst. The results showed that when introducing Bi2MoO6, the light absorption range of the Bi2MoO6/CoMoO4 heterojunctions were significantly enhanced, and the separation of photogenerated charges were also improved. Methylene blue and ceftriaxone sodium were used as pollutants to simulate wastewater, and the photocatalytic degradation activity of the catalyst samples was evaluated under visible light. After irradiation for 60 min, the composite with Bi2MoO6 loading of 30%(w/w) composites has the best photocatalytic performance, and the degradation rate constant was twice that of pure CoMoO4. Based on all the experimental characterizations, the corresponding photocatalytic mechanism of the Bi2MoO6/CoMoO4 system was further studied.
Herein, Bi2MoO6/CoMoO4 embroidery ball structures were synthesized by a simple one-step hydrothermal method that using bismuth nitrate pentahydrate as the bismuth source. By X-ray powder diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), Fourier infrared spectroscopy (FT-IR), ultraviolet-visible diffuse reflection spectroscopy (UV-Vis DRS), fluorescence spectrum (PL), and electrochemical tests were performed to analyze the phase composition, micromorphology, optical properties, and recombination rate of photogenerated charge of the prepared catalyst. The results showed that when introducing Bi2MoO6, the light absorption range of the Bi2MoO6/CoMoO4 heterojunctions were significantly enhanced, and the separation of photogenerated charges were also improved. Methylene blue and ceftriaxone sodium were used as pollutants to simulate wastewater, and the photocatalytic degradation activity of the catalyst samples was evaluated under visible light. After irradiation for 60 min, the composite with Bi2MoO6 loading of 30%(w/w) composites has the best photocatalytic performance, and the degradation rate constant was twice that of pure CoMoO4. Based on all the experimental characterizations, the corresponding photocatalytic mechanism of the Bi2MoO6/CoMoO4 system was further studied.
2020, 36(8): 1457-1464
doi: 10.11862/CJIC.2020.160
Abstract:
In-situ chemical reaction and heat treatment were used to form a wire-like and petal-shaped three-dimensional inorganic substance array on the surface of copper foam, and then Ag nanoparticles (NPs) were deposited on its surface to successfully prepare Ag/CuO composite photothermal material. The composite material has high solar light absorption capacity due to the surface three-dimensional array structure and plasmonic effect caused by Ag NPs. This material combined with melamine foam as evaporation device can achieve highly efficient seawater desalination. In addition, to study the optical trap depth and the metal doping for enhancement of the photothermal conversion efficiency, solar steam generation test system was built to investigate the photothermal evaporation performance of the sample. Under one solar (1 kW·m-2) irradiation, evaporation rate of this device was as high as 1.097 6 kg·m-2· h-1, and its evaporation efficiency could reach 78.38%.
In-situ chemical reaction and heat treatment were used to form a wire-like and petal-shaped three-dimensional inorganic substance array on the surface of copper foam, and then Ag nanoparticles (NPs) were deposited on its surface to successfully prepare Ag/CuO composite photothermal material. The composite material has high solar light absorption capacity due to the surface three-dimensional array structure and plasmonic effect caused by Ag NPs. This material combined with melamine foam as evaporation device can achieve highly efficient seawater desalination. In addition, to study the optical trap depth and the metal doping for enhancement of the photothermal conversion efficiency, solar steam generation test system was built to investigate the photothermal evaporation performance of the sample. Under one solar (1 kW·m-2) irradiation, evaporation rate of this device was as high as 1.097 6 kg·m-2· h-1, and its evaporation efficiency could reach 78.38%.
2020, 36(8): 1465-1474
doi: 10.11862/CJIC.2020.111
Abstract:
A uniform LiNi0.80Co0.15Al0.05O2 microsphere materials (NCA) with tap density of 1.86~2.07 g·cm-3 were successfully prepared using co-precipitation method assisted by surfactants polyethylene glycol (PEG) or polyvinylpyrrolidone (PVP). Crystal structure, particles morphology and electrochemical features were evaluated through X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscope (SEM), cyclic voltammogram (CV), electrochemical impedance spectra (EIS) and charge/discharge studies. The results showed that the atomic ratio of Ni, Co and Al could not be affected in the materials which were synthesized with PEG or PVP and the materials had high tap density. The result of XRD showed that all the diffraction peaks of NCA materials were indexed to the pure α-NaFeO2 layered structure which belonged to R3m space group. SEM images of precursors and NCA materials were obvious that the growth of primary grains was improved with the addition of PVP and PEG. The NCA obtained with the addition of PEG and PVP displayed a high discharge capacity of 210.8 and 188.9 mAh·g-1 at 0.2C, and showed good capacity retention of 78.8% and 93.2% after 100 cycles respectively, which were better than that of NCA obtained without surfactant (173.0 mAh·g-1 and 82.7%). EIS curves showed that electrochemical impedance of NCA-2 electrode least than NCA-1 and NCA-3 after 100 cycles. SEM images of positive plates after 200 cycles were obvious that positive plates synthesized by using PVP had least cracks and particle fragmentation. NCA-2 showed better capacity retention than NCA obtained with the addition of PEG and NCA obtained without surfactant.
A uniform LiNi0.80Co0.15Al0.05O2 microsphere materials (NCA) with tap density of 1.86~2.07 g·cm-3 were successfully prepared using co-precipitation method assisted by surfactants polyethylene glycol (PEG) or polyvinylpyrrolidone (PVP). Crystal structure, particles morphology and electrochemical features were evaluated through X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscope (SEM), cyclic voltammogram (CV), electrochemical impedance spectra (EIS) and charge/discharge studies. The results showed that the atomic ratio of Ni, Co and Al could not be affected in the materials which were synthesized with PEG or PVP and the materials had high tap density. The result of XRD showed that all the diffraction peaks of NCA materials were indexed to the pure α-NaFeO2 layered structure which belonged to R3m space group. SEM images of precursors and NCA materials were obvious that the growth of primary grains was improved with the addition of PVP and PEG. The NCA obtained with the addition of PEG and PVP displayed a high discharge capacity of 210.8 and 188.9 mAh·g-1 at 0.2C, and showed good capacity retention of 78.8% and 93.2% after 100 cycles respectively, which were better than that of NCA obtained without surfactant (173.0 mAh·g-1 and 82.7%). EIS curves showed that electrochemical impedance of NCA-2 electrode least than NCA-1 and NCA-3 after 100 cycles. SEM images of positive plates after 200 cycles were obvious that positive plates synthesized by using PVP had least cracks and particle fragmentation. NCA-2 showed better capacity retention than NCA obtained with the addition of PEG and NCA obtained without surfactant.
2020, 36(8): 1475-1484
doi: 10.11862/CJIC.2020.153
Abstract:
Carboxylated magnetic microsphere Fe3O4-COOH was firstly synthesized by solvothermal method. MIL-101(Cr) functionalized magnetic composite Fe3O4-COOH@MIL-101(Cr) was obtained next by one-pot method. Phosphotungstic acid was finally grafted on the Fe3O4-COOH@MIL-101(Cr) by ultrasonic impregnation method to obtain HPW@Fe3O4-COOH@MIL-101(Cr). Its composition and morphology were characterized by Fourier transform infrared spectrum (FT-IR), X-ray diffraction (XRD), X-ray photoelectron spectrometer (XPS), Vibrating sample magnetometer (VSM), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). It was used as catalyst with hydrogen peroxide as oxidant to catalyze the oxidation of n-octane simulated oil sample with dibenzothiophene as sulfur source. The effects of ultrasonic reaction time, oxidant dosage, reaction temperature, dosage of the phase transfer agent and the catalyst amount on the desulfurization rate were investigated by using single factor method. The presumed mechanism was discussed. The results showed that the optimized catalytic degradation rate reached when the reaction time was at 60℃, 5 mins, nH2O2/nS of 4, usage amount of the phase transfer agent CTAB at 0.2%(w/w), with the catalyst amount of 8 g·L-1. The catalytic degradation rate reached 73.15%. After used for 5 times, the catalytic degradation rate decreased by 7.8%, indicating that the material has good catalytic desulfurization performance and can be reused. Primary mechanism study showed that the active center for the catalytic desulfurization might be the heteropoly acid anion of the HPW@Fe3O4-COOH@MIL-101(Cr), in which the Fe3O4-COOH@MIL-101(Cr) may act as a supporter and cooperative absorbent.
Carboxylated magnetic microsphere Fe3O4-COOH was firstly synthesized by solvothermal method. MIL-101(Cr) functionalized magnetic composite Fe3O4-COOH@MIL-101(Cr) was obtained next by one-pot method. Phosphotungstic acid was finally grafted on the Fe3O4-COOH@MIL-101(Cr) by ultrasonic impregnation method to obtain HPW@Fe3O4-COOH@MIL-101(Cr). Its composition and morphology were characterized by Fourier transform infrared spectrum (FT-IR), X-ray diffraction (XRD), X-ray photoelectron spectrometer (XPS), Vibrating sample magnetometer (VSM), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). It was used as catalyst with hydrogen peroxide as oxidant to catalyze the oxidation of n-octane simulated oil sample with dibenzothiophene as sulfur source. The effects of ultrasonic reaction time, oxidant dosage, reaction temperature, dosage of the phase transfer agent and the catalyst amount on the desulfurization rate were investigated by using single factor method. The presumed mechanism was discussed. The results showed that the optimized catalytic degradation rate reached when the reaction time was at 60℃, 5 mins, nH2O2/nS of 4, usage amount of the phase transfer agent CTAB at 0.2%(w/w), with the catalyst amount of 8 g·L-1. The catalytic degradation rate reached 73.15%. After used for 5 times, the catalytic degradation rate decreased by 7.8%, indicating that the material has good catalytic desulfurization performance and can be reused. Primary mechanism study showed that the active center for the catalytic desulfurization might be the heteropoly acid anion of the HPW@Fe3O4-COOH@MIL-101(Cr), in which the Fe3O4-COOH@MIL-101(Cr) may act as a supporter and cooperative absorbent.
2020, 36(8): 1485-1491
doi: 10.11862/CJIC.2020.145
Abstract:
The different rare earth (Gd3+, La3+) doped Eu(p-MOBA)3phen probe molecules were prepared by using rare earth oxides (Eu2O3, Gd2O3, La2O3), p-methoxybenzoic acid (p-MOBA) and phenanthroline (phen). The different rare earth (Gd3+, La3+) doped Eu(p-MOBA)3phen/PMMA temperature sensitive paints (TSPs) were fabricated by mixing the probe molecules with methyl methacrylate (MMA) and initiating polymerization with benzoyl peroxide (BPO). The morphology, structure, luminescence properties of the probe molecules, and the fluorescence temperature quenching property of the TSPs were characterized by scanning electron microscopy, UV-Vis absorption spectra, infrared spectrometer and fluorescence spectra. The infrared spectrum, UV-Vis absorption spectra and scanning electron microscopy spectra show that Eu3+ was successfully coordinated with the ligands p-MOBA and phen, and the structure of Eu(p-MOBA)3phen was not changed when doped with rare earth ions (Gd3+, La3+), indicating that the doping of rare earth ions (Gd3+, La3+) partially replaced Eu3+. The fluorescence spectrum shows that the addition of rare earth ions (Gd3+, La3+) have a gain effect on the luminescence of Eu(p-MOBA)3phen, and the corresponding TSPs have good fluorescence temperature quenching property in the temperature range of 50~100℃. Compared with La3+ doped Eu(p-MOBA)3phen/PMMA, Gd3+ doped Eu(p-MOBA)3phen/PMMA has stronger fluorescence emission and higher temperature sensitivity. It can be seen that different rare earths (Gd3+, La3+) have different effects on the fluorescence and temperature sensitivity properties of Eu(p-MOBA)3phen/PMMA.
The different rare earth (Gd3+, La3+) doped Eu(p-MOBA)3phen probe molecules were prepared by using rare earth oxides (Eu2O3, Gd2O3, La2O3), p-methoxybenzoic acid (p-MOBA) and phenanthroline (phen). The different rare earth (Gd3+, La3+) doped Eu(p-MOBA)3phen/PMMA temperature sensitive paints (TSPs) were fabricated by mixing the probe molecules with methyl methacrylate (MMA) and initiating polymerization with benzoyl peroxide (BPO). The morphology, structure, luminescence properties of the probe molecules, and the fluorescence temperature quenching property of the TSPs were characterized by scanning electron microscopy, UV-Vis absorption spectra, infrared spectrometer and fluorescence spectra. The infrared spectrum, UV-Vis absorption spectra and scanning electron microscopy spectra show that Eu3+ was successfully coordinated with the ligands p-MOBA and phen, and the structure of Eu(p-MOBA)3phen was not changed when doped with rare earth ions (Gd3+, La3+), indicating that the doping of rare earth ions (Gd3+, La3+) partially replaced Eu3+. The fluorescence spectrum shows that the addition of rare earth ions (Gd3+, La3+) have a gain effect on the luminescence of Eu(p-MOBA)3phen, and the corresponding TSPs have good fluorescence temperature quenching property in the temperature range of 50~100℃. Compared with La3+ doped Eu(p-MOBA)3phen/PMMA, Gd3+ doped Eu(p-MOBA)3phen/PMMA has stronger fluorescence emission and higher temperature sensitivity. It can be seen that different rare earths (Gd3+, La3+) have different effects on the fluorescence and temperature sensitivity properties of Eu(p-MOBA)3phen/PMMA.
2020, 36(8): 1492-1498
doi: 10.11862/CJIC.2020.163
Abstract:
We utilize a simple one-step hydrothermal synthesis method to introduce trace amount of W6+ into Fe0.02Ni(OH)2 LDH, which grow on nickel foam in situ. The morphology, composition and structure of W0.03Fe0.2Ni(OH)2 LDH were characterized by means of field emission scanning electron microscope (FESEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectra, and so on. W0.03Fe0.2Ni(OH)2 LDH exhibited better electrochemical performance than others due to W6+ introduction. Electrochemical tests show that the lowest overpotentials for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) at the 25 mA·cm-2 were only 271 and 208 mV, respectively. The corresponding Tafel slopes were 61 and 181 mV·dec-1. In addition, there were no obvious decrease of electrocatalytic activity after more than 20-hours of chronopotentiometric test.
We utilize a simple one-step hydrothermal synthesis method to introduce trace amount of W6+ into Fe0.02Ni(OH)2 LDH, which grow on nickel foam in situ. The morphology, composition and structure of W0.03Fe0.2Ni(OH)2 LDH were characterized by means of field emission scanning electron microscope (FESEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectra, and so on. W0.03Fe0.2Ni(OH)2 LDH exhibited better electrochemical performance than others due to W6+ introduction. Electrochemical tests show that the lowest overpotentials for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) at the 25 mA·cm-2 were only 271 and 208 mV, respectively. The corresponding Tafel slopes were 61 and 181 mV·dec-1. In addition, there were no obvious decrease of electrocatalytic activity after more than 20-hours of chronopotentiometric test.
2020, 36(8): 1499-1505
doi: 10.11862/CJIC.2020.144
Abstract:
One-step hydrothermal synthesis was used to prepare spherical Bi2WO6 and Ag/Bi2WO6 photocatalysts, and the properties of the samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), ultravioletvisible spectrophotometry (UV-Vis) and other means. Under the condition of simulating sunlight, the catalytic activity and mechanism of Bi2WO6 and Ag/Bi2WO6 were studied using methyl orange (MO) as degradation product. The results show that compared with Bi2WO6, Ag/Bi2WO6 has a better degradation effect on MO under the same conditions. When the Ag doping amount was 1%(n/n), the degradation rate (180 min) reached 91.4%, and the degradation rate of the recovered sample was also obtained, which also reached 81%. In addition, a preliminary study of the degradation mechanism of Ag/Bi2WO6 composites was also performed.
One-step hydrothermal synthesis was used to prepare spherical Bi2WO6 and Ag/Bi2WO6 photocatalysts, and the properties of the samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), ultravioletvisible spectrophotometry (UV-Vis) and other means. Under the condition of simulating sunlight, the catalytic activity and mechanism of Bi2WO6 and Ag/Bi2WO6 were studied using methyl orange (MO) as degradation product. The results show that compared with Bi2WO6, Ag/Bi2WO6 has a better degradation effect on MO under the same conditions. When the Ag doping amount was 1%(n/n), the degradation rate (180 min) reached 91.4%, and the degradation rate of the recovered sample was also obtained, which also reached 81%. In addition, a preliminary study of the degradation mechanism of Ag/Bi2WO6 composites was also performed.
2020, 36(8): 1506-1514
doi: 10.11862/CJIC.2020.166
Abstract:
One-step carbonization method was used to prepare CoO rich porous carbon (PC(Co)) materials as carrier of tin oxide (SnO2). PC(Co) materials have rich porous structure which can efficiently carry SnO2. Furthermore, the CoO in the PC(Co) materials can act on the electrochemical reaction, effectively reducing the formation of LiO2. But cobalt oxide can consume a lot of lithium ions, so we chose to add lithium fluoride (LiF) which can while replenishing lithium and enhance the stability of the SEI film. By calculation, the loading of the active substance was as high as 1.51 mg·cm-2. Electrochemical tests show that at a current density of 100 mAh·g-1, the first discharge specific capacity reached 1 653.63 mAh·g-1, and the utilization rate of the active material was as high as 93.14%. After 100 cycles, the specific discharge capacity still reached 1 070.68 mAh·g-1, and the coulombic efficiency remained at 99.81%.
One-step carbonization method was used to prepare CoO rich porous carbon (PC(Co)) materials as carrier of tin oxide (SnO2). PC(Co) materials have rich porous structure which can efficiently carry SnO2. Furthermore, the CoO in the PC(Co) materials can act on the electrochemical reaction, effectively reducing the formation of LiO2. But cobalt oxide can consume a lot of lithium ions, so we chose to add lithium fluoride (LiF) which can while replenishing lithium and enhance the stability of the SEI film. By calculation, the loading of the active substance was as high as 1.51 mg·cm-2. Electrochemical tests show that at a current density of 100 mAh·g-1, the first discharge specific capacity reached 1 653.63 mAh·g-1, and the utilization rate of the active material was as high as 93.14%. After 100 cycles, the specific discharge capacity still reached 1 070.68 mAh·g-1, and the coulombic efficiency remained at 99.81%.
2020, 36(8): 1515-1523
doi: 10.11862/CJIC.2020.169
Abstract:
A solid composite electrolyte was prepared through a solution-casting method with polypropylene carbonate (PPC) and polyethylene oxide (PEO) as polymer blends, and Li6.4La3Zr1.4Ta0.6O12(LLZTO) particles as multifunctional fillers. The effects of LLZTO content and PPC/PEO mass ratio on the ionic conductivity of solid composite electrolyte were studied. Results show that the ionic conductivity at room temperature reached the highest value of 1.14×10-4 S·cm-1 when LLZTO content was 30%(w/w) and the mass ratio of PPC to PEO was 1:1. The incorporation of LLZTO and PPC into PEO repressed the crystallinity of polymer electrolyte, increased ionic conductivity, electrochemical stability window (4.7 V) and Li+ transference number (0.25), and reinforces interfacial stability between solid electrolyte and lithium anode. The capacity retention rates of the LiFePO4/Li cell with solid composite electrolyte remain 82% after 70 cycles at room temperature and 79% after 100 cycles at 60℃. The discharge capacity reaches 120.7 and 112.6 mAh·g-1 at 0.5C and 1C, respectively.
A solid composite electrolyte was prepared through a solution-casting method with polypropylene carbonate (PPC) and polyethylene oxide (PEO) as polymer blends, and Li6.4La3Zr1.4Ta0.6O12(LLZTO) particles as multifunctional fillers. The effects of LLZTO content and PPC/PEO mass ratio on the ionic conductivity of solid composite electrolyte were studied. Results show that the ionic conductivity at room temperature reached the highest value of 1.14×10-4 S·cm-1 when LLZTO content was 30%(w/w) and the mass ratio of PPC to PEO was 1:1. The incorporation of LLZTO and PPC into PEO repressed the crystallinity of polymer electrolyte, increased ionic conductivity, electrochemical stability window (4.7 V) and Li+ transference number (0.25), and reinforces interfacial stability between solid electrolyte and lithium anode. The capacity retention rates of the LiFePO4/Li cell with solid composite electrolyte remain 82% after 70 cycles at room temperature and 79% after 100 cycles at 60℃. The discharge capacity reaches 120.7 and 112.6 mAh·g-1 at 0.5C and 1C, respectively.
2020, 36(8): 1524-1534
doi: 10.11862/CJIC.2020.167
Abstract:
In this work, a very simple and cost-effective two-step solid state reaction method for the preparation of NiSe nanocrystalline restricted within N, Se-codoped carbon scaffold was presented. By directly grinding nickel acetate tetrahydrate, o-vanillin and o-phenylenediamine together with a molar ratio of 1:2:1 at room temperature, a self -assembly solid state reaction took place to give rise to a bis-Schiff base complex with Ni(Ⅱ). After subsequent annealing at 700℃ in the presence of selenium powder, simultaneous carbonization and selenization occurred, resulting in the in -situ formation of NiSe nanocrystalline (~100 nm) confined within an irregular N, Se-codoped carbon scaffold (denoted as NiSe⊂NSeC). By means of X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA), the phase, morphology, composition and mass content for the NiSe ⊂ NSeC composite were identified. Its electrochemical sodium storage performance was tested by cyclic voltammetry, constant current charge and discharge cycling process, and electrochemical impedance spectrum. When tested as an anode material for sodium-ion batteries (SIBs), the NiSe⊂NSeC composite exhibited an impressive electrochemical sodium storage performance in terms of long-term cycling stability (291 mAh·g-1 of charging capacity after 100 cycles at 0.1 A·g-1, with a 88% of charging capacity retention compared with the first cycle) and excellent rate capability (197 mAh·g-1 of charging capacity at 5 A·g-1).
In this work, a very simple and cost-effective two-step solid state reaction method for the preparation of NiSe nanocrystalline restricted within N, Se-codoped carbon scaffold was presented. By directly grinding nickel acetate tetrahydrate, o-vanillin and o-phenylenediamine together with a molar ratio of 1:2:1 at room temperature, a self -assembly solid state reaction took place to give rise to a bis-Schiff base complex with Ni(Ⅱ). After subsequent annealing at 700℃ in the presence of selenium powder, simultaneous carbonization and selenization occurred, resulting in the in -situ formation of NiSe nanocrystalline (~100 nm) confined within an irregular N, Se-codoped carbon scaffold (denoted as NiSe⊂NSeC). By means of X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA), the phase, morphology, composition and mass content for the NiSe ⊂ NSeC composite were identified. Its electrochemical sodium storage performance was tested by cyclic voltammetry, constant current charge and discharge cycling process, and electrochemical impedance spectrum. When tested as an anode material for sodium-ion batteries (SIBs), the NiSe⊂NSeC composite exhibited an impressive electrochemical sodium storage performance in terms of long-term cycling stability (291 mAh·g-1 of charging capacity after 100 cycles at 0.1 A·g-1, with a 88% of charging capacity retention compared with the first cycle) and excellent rate capability (197 mAh·g-1 of charging capacity at 5 A·g-1).
2020, 36(8): 1535-1542
doi: 10.11862/CJIC.2020.174
Abstract:
Bi deposited Yb3+, Er3+ codped TiO2 nanofiber photocatalysts were synthesized from Yb3+ and Er3+ co-doped TiO2 substrate by combining electrospinning technique and hydrothermal method. Using triethanolamine as a sacrificial agent, we studied the ultraviolet, visible, near infrared and full spectrum photocatalytic hydrogen production over Bi/Yb3+, Er3+:TiO2. The results showed that the full-spectrum illumination for 5 h resulted in a hydrogen production rate of 1 650.3 μmol·g-1·h-1. As an emerging non-noble metal, Bi displays unique plasma photocatalytic or assisted photocatalytic properties. The advantages of Bi metal can be further combined with a rich energy level structure of rare earth elements and unique up-conversion luminescence properties. The double synergistic modification of TiO2 can effectively improve the photocatalytic activity of TiO2 nanofibers.
Bi deposited Yb3+, Er3+ codped TiO2 nanofiber photocatalysts were synthesized from Yb3+ and Er3+ co-doped TiO2 substrate by combining electrospinning technique and hydrothermal method. Using triethanolamine as a sacrificial agent, we studied the ultraviolet, visible, near infrared and full spectrum photocatalytic hydrogen production over Bi/Yb3+, Er3+:TiO2. The results showed that the full-spectrum illumination for 5 h resulted in a hydrogen production rate of 1 650.3 μmol·g-1·h-1. As an emerging non-noble metal, Bi displays unique plasma photocatalytic or assisted photocatalytic properties. The advantages of Bi metal can be further combined with a rich energy level structure of rare earth elements and unique up-conversion luminescence properties. The double synergistic modification of TiO2 can effectively improve the photocatalytic activity of TiO2 nanofibers.
Electrochemical Preparation of MoS2 Intercalated Compound with Micron Size for Magnesium-Ion Storage
2020, 36(8): 1543-1549
doi: 10.11862/CJIC.2020.173
Abstract:
The micro-sized MoS2 intercalated compound with the intercalant of 1-butyl-3-methyl-imidazolium cation (BMIM+) was prepared by a simple electrochemical method and used as cathode material of magnesium ion batteries. The MoS2 intercalated compound (denoted as MoS2-BMIM+) has an expanded interlayer spacing of 0.98 nm, which effectively reduced the insertion/extraction barrier of Mg2+ and provided abundant active sites for Mg2+ intercalation. Therefore, the MoS2-BMIM+ deliverd a significantly improved charging capacity (101.93 mAh·g-1 at 20 mA· g-1, about 4 times as much as bulk MoS2) and a good rate performance. We further show that this method can also be applied for the intercalation of 1-butyl-1-methylpyrrolidinium cation (Pyr14+), which showed an interlayer spacing of 1.04 nm.
The micro-sized MoS2 intercalated compound with the intercalant of 1-butyl-3-methyl-imidazolium cation (BMIM+) was prepared by a simple electrochemical method and used as cathode material of magnesium ion batteries. The MoS2 intercalated compound (denoted as MoS2-BMIM+) has an expanded interlayer spacing of 0.98 nm, which effectively reduced the insertion/extraction barrier of Mg2+ and provided abundant active sites for Mg2+ intercalation. Therefore, the MoS2-BMIM+ deliverd a significantly improved charging capacity (101.93 mAh·g-1 at 20 mA· g-1, about 4 times as much as bulk MoS2) and a good rate performance. We further show that this method can also be applied for the intercalation of 1-butyl-1-methylpyrrolidinium cation (Pyr14+), which showed an interlayer spacing of 1.04 nm.
2020, 36(8): 1550-1556
doi: 10.11862/CJIC.2020.180
Abstract:
Three new complexes[Zn(2, 2'-oba) (bipy)2] ·2H2O (1), [Pb(2, 2'-oba) (phen)]n (2) and {[Pb(2, 2'-oba) (bimbp)]·H2O}n (3) (2, 2'-H2oba=2, 2'-oxybis(benzoic acid), bipy=2, 2'-bipyridine, phen=1, 10-phenanthroline, bimbp=4, 4'-bis(imidazolyl)biphenyl) were synthesized by hydrothermal reactions and characterized by single-crystal X-ray diffraction, thermogravimetric analyses, IR spectroscopy and elemental analysis. Complex 1 is a 0D structure, which is extended to a 2D supramolecular framework through aromatic π-π stacking interactions and strong intermolecular O-H…O hydrogen bonds. Complex 2 shows a 1D chain structure, which is expanded to a 2D layer structure through aromatic π-π stacking interactions. Complex 3 appears a 1D double chain structure, which is further extended to a 2D supramolecular framework through strong intermolecular O-H…O hydrogen bonds. Moreover, the solid-state fluorescent properties of 1~3 have also been investigated. According to the crystal structures, the TDDFT/6-31G(d) approach was applied to study the photoluminescence emission of 1, and the calculated results are in good agreement with the experimental results.
Three new complexes[Zn(2, 2'-oba) (bipy)2] ·2H2O (1), [Pb(2, 2'-oba) (phen)]n (2) and {[Pb(2, 2'-oba) (bimbp)]·H2O}n (3) (2, 2'-H2oba=2, 2'-oxybis(benzoic acid), bipy=2, 2'-bipyridine, phen=1, 10-phenanthroline, bimbp=4, 4'-bis(imidazolyl)biphenyl) were synthesized by hydrothermal reactions and characterized by single-crystal X-ray diffraction, thermogravimetric analyses, IR spectroscopy and elemental analysis. Complex 1 is a 0D structure, which is extended to a 2D supramolecular framework through aromatic π-π stacking interactions and strong intermolecular O-H…O hydrogen bonds. Complex 2 shows a 1D chain structure, which is expanded to a 2D layer structure through aromatic π-π stacking interactions. Complex 3 appears a 1D double chain structure, which is further extended to a 2D supramolecular framework through strong intermolecular O-H…O hydrogen bonds. Moreover, the solid-state fluorescent properties of 1~3 have also been investigated. According to the crystal structures, the TDDFT/6-31G(d) approach was applied to study the photoluminescence emission of 1, and the calculated results are in good agreement with the experimental results.
2020, 36(8): 1557-1566
doi: 10.11862/CJIC.2020.179
Abstract:
Carbon dots (CDs) with various chemical structures can be obtained under the condition of different heat treat temperatures. The morphology and phase of CaCO3 has been successfully controlled by the as-prepared CDs. Peanut-like, dumbbell-like and sphere-like particles were prepared in the presence of CDs. The CDs with changeable chemical structures, such as carboxyl group, aldehyde group, hydroxyl group, were deemed to be responsible for the variation in morphology. The as-obtained samples were characterized by scanning electron microscope (SEM), Fourier transform infrared spectrometer (FTIR), photoluminescence (PL) and X-ray diffraction (XRD). The growth mechanism of CaCO3 twin sphere particles was investigated in detail. Ostwald ripening and oriented aggregation mechanisms were proposed to be the drive power of the final morphology formation in the presence of CDs.
Carbon dots (CDs) with various chemical structures can be obtained under the condition of different heat treat temperatures. The morphology and phase of CaCO3 has been successfully controlled by the as-prepared CDs. Peanut-like, dumbbell-like and sphere-like particles were prepared in the presence of CDs. The CDs with changeable chemical structures, such as carboxyl group, aldehyde group, hydroxyl group, were deemed to be responsible for the variation in morphology. The as-obtained samples were characterized by scanning electron microscope (SEM), Fourier transform infrared spectrometer (FTIR), photoluminescence (PL) and X-ray diffraction (XRD). The growth mechanism of CaCO3 twin sphere particles was investigated in detail. Ostwald ripening and oriented aggregation mechanisms were proposed to be the drive power of the final morphology formation in the presence of CDs.
2020, 36(8): 1567-1572
doi: 10.11862/CJIC.2020.178
Abstract:
A pentanuclear Sn(Ⅱ) guanidinate complex[PhNC(NMe)2N(H)SnCl]2[PhNC(NMe)2NSnCl]2Sn (1) was synthesized via the reaction of PhN(Li)SiMe3 and anhydrous tin(Ⅱ) chloride. It was well structurally characterized by 1H NMR, 13C NMR, elemental analysis, and X-ray single crystal crystallography techniques. Complex 1 is an active catalyst in the addition reaction of arylamines into N, N'-diisopropylcarbodiimide giving guanidinates. CCDC:1954650.
A pentanuclear Sn(Ⅱ) guanidinate complex[PhNC(NMe)2N(H)SnCl]2[PhNC(NMe)2NSnCl]2Sn (1) was synthesized via the reaction of PhN(Li)SiMe3 and anhydrous tin(Ⅱ) chloride. It was well structurally characterized by 1H NMR, 13C NMR, elemental analysis, and X-ray single crystal crystallography techniques. Complex 1 is an active catalyst in the addition reaction of arylamines into N, N'-diisopropylcarbodiimide giving guanidinates. CCDC:1954650.
2020, 36(8): 1573-1581
doi: 10.11862/CJIC.2020.114
Abstract:
Shiitake-derived nitrogen-doped microporous carbon materials were prepared by a simple activation/carbonization process. It was found that the nitrogen content was enhanced owing to the consumption of carbon in the activation process, and that the pyridinic nitrogen groups were promoted after activation. The microporous carbons offered a high specific surface area of 1 930 m2·g-1 with a high micropore surface area of 1 594 m2·g-1. The high micropore surface area accompanied with rich nitrogen and oxygen groups contributed to a remarkable specific capacitance of 325 F·g-1 at 0.5 A·g-1 and high rate capability. In addition, shiitake-derived microporous carbons presented robust cycling stability with 2.3% capacitance loss during 5 000 cycles, and a high specific capacitance of 203 F·g-1 at 0.5 A·g-1 in symmetric supercapacitors. The high performance could be attributed to the high surface area, enhancing electric double layer capacitance, and numerous nitrogen groups.
Shiitake-derived nitrogen-doped microporous carbon materials were prepared by a simple activation/carbonization process. It was found that the nitrogen content was enhanced owing to the consumption of carbon in the activation process, and that the pyridinic nitrogen groups were promoted after activation. The microporous carbons offered a high specific surface area of 1 930 m2·g-1 with a high micropore surface area of 1 594 m2·g-1. The high micropore surface area accompanied with rich nitrogen and oxygen groups contributed to a remarkable specific capacitance of 325 F·g-1 at 0.5 A·g-1 and high rate capability. In addition, shiitake-derived microporous carbons presented robust cycling stability with 2.3% capacitance loss during 5 000 cycles, and a high specific capacitance of 203 F·g-1 at 0.5 A·g-1 in symmetric supercapacitors. The high performance could be attributed to the high surface area, enhancing electric double layer capacitance, and numerous nitrogen groups.
2020, 36(8): 1582-1592
doi: 10.11862/CJIC.2020.168
Abstract:
In this work, the development of efficient and stable photocatalyst has been the central topic of scientific research. Herein, MoS2 nanosheets/tubular-like g-C3N4 (MS/TCN) composite photocatalysts with two dimension/one dimension (2D/1D) nanostructure were fabricated through a facile solvothermal method for photocatalytic hydrogen production from seawater under visible light irradiation, exhibiting enhanced photocatalytic performance in comparison of single MS or TCN. Among of them, MS/TCN-0.5 sample (0.5%(w/w) MoS2) showed optimum H2 evolution rate of 85.1 μmol·h-1 and possessed outstanding stability (no significant decrease after 4 cycles). The enhanced photocatalytic activity of MS/TCN composite photocatalyst can be attributed to the fact that the loading of 2D MS, as a cocatalyst, promotes the transfer of photo-induced electron and improves the separation efficiency of electron-hole pairs of 1D TCN.
In this work, the development of efficient and stable photocatalyst has been the central topic of scientific research. Herein, MoS2 nanosheets/tubular-like g-C3N4 (MS/TCN) composite photocatalysts with two dimension/one dimension (2D/1D) nanostructure were fabricated through a facile solvothermal method for photocatalytic hydrogen production from seawater under visible light irradiation, exhibiting enhanced photocatalytic performance in comparison of single MS or TCN. Among of them, MS/TCN-0.5 sample (0.5%(w/w) MoS2) showed optimum H2 evolution rate of 85.1 μmol·h-1 and possessed outstanding stability (no significant decrease after 4 cycles). The enhanced photocatalytic activity of MS/TCN composite photocatalyst can be attributed to the fact that the loading of 2D MS, as a cocatalyst, promotes the transfer of photo-induced electron and improves the separation efficiency of electron-hole pairs of 1D TCN.
2020, 36(8): 1593-1604
doi: 10.11862/CJIC.2020.175
Abstract:
Two novel nano-materials M3SiW9 (M=Cu(Ⅱ), Co(Ⅱ)) based on polyoxometalate have been successfully synthesized by chemical precipitation method using trivacant Keggin-type silicotungstate as precursor. Cu3SiW9 exhibited extremely rare nanowhisker morphology in polyoxometalate-based nano-materials and Co3SiW9 simultaneously showed uniform nanosphere morphology. Control experiments were implemented to indicate the morphologies of M3SiW9 could be tuned by doping different transition metals. Furthermore, fluorescein sodium was employed as dopant to endow nanowhiskers with an emission peak at 510 nm. Moreover, the nanowhiskers were also used as carriers to combine with CdS quantum dots to improve the photocatalytic property. The results show that when the mass ratio of Cu3SiW9 to CdS was 1:1, the hydrogen production efficiency of the composite was about 10 times that of pure CdS quantum dots. This also confirms that the presence of polyoxometalate can effectively inhibit the recombination of CdS quantum dot photogenerated electrons and holes, thereby greatly improving the efficiency of photolysis of water to produce hydrogen.
Two novel nano-materials M3SiW9 (M=Cu(Ⅱ), Co(Ⅱ)) based on polyoxometalate have been successfully synthesized by chemical precipitation method using trivacant Keggin-type silicotungstate as precursor. Cu3SiW9 exhibited extremely rare nanowhisker morphology in polyoxometalate-based nano-materials and Co3SiW9 simultaneously showed uniform nanosphere morphology. Control experiments were implemented to indicate the morphologies of M3SiW9 could be tuned by doping different transition metals. Furthermore, fluorescein sodium was employed as dopant to endow nanowhiskers with an emission peak at 510 nm. Moreover, the nanowhiskers were also used as carriers to combine with CdS quantum dots to improve the photocatalytic property. The results show that when the mass ratio of Cu3SiW9 to CdS was 1:1, the hydrogen production efficiency of the composite was about 10 times that of pure CdS quantum dots. This also confirms that the presence of polyoxometalate can effectively inhibit the recombination of CdS quantum dot photogenerated electrons and holes, thereby greatly improving the efficiency of photolysis of water to produce hydrogen.
2020, 36(8): 1605-1612
doi: 10.11862/CJIC.2020.176
Abstract:
In this work, under the regulation of citric acid, SnO2 nanorods were synthesized by hydrothermal method. The structural characteristics of SnO 2 samples during the growth process was investigated by using high-resolution transmission electron microscope, X-ray diffraction, infrared spectra Fourier transform spectra, Brunauer-EmmettTeller nitrogen physisorption, UV-visible diffuse reflection spectrum, and photoluminescence spectra. The results reveal that the overall crystal growth can further be divided into two stages:the oriented attachment of SnO2 nanocrystals at the early stage and subsequently a slow crystal growth along the [001] direction following the Ostwald ripening mode. Photoluminescence property and photocatalytic activity of SnO2 nanoparticles at the different stages was also investigated, which show a similar changing trend with the crystal growing:greatly increased at the former stage and gradually decreased at the latter stage.
In this work, under the regulation of citric acid, SnO2 nanorods were synthesized by hydrothermal method. The structural characteristics of SnO 2 samples during the growth process was investigated by using high-resolution transmission electron microscope, X-ray diffraction, infrared spectra Fourier transform spectra, Brunauer-EmmettTeller nitrogen physisorption, UV-visible diffuse reflection spectrum, and photoluminescence spectra. The results reveal that the overall crystal growth can further be divided into two stages:the oriented attachment of SnO2 nanocrystals at the early stage and subsequently a slow crystal growth along the [001] direction following the Ostwald ripening mode. Photoluminescence property and photocatalytic activity of SnO2 nanoparticles at the different stages was also investigated, which show a similar changing trend with the crystal growing:greatly increased at the former stage and gradually decreased at the latter stage.
