Physical chemistry chemical physics : PCCP, Jan 12, 2016
Herein, we demonstrate experimentally the coexistence of photocatalytic dual opposite roles of Au... more Herein, we demonstrate experimentally the coexistence of photocatalytic dual opposite roles of Au nanoparticles in a UV-vis light irradiated Au/TiO2 system. We have investigated that the photocatalytic performance curves of Au/TiO2 and CdS/Au/TiO2 for degradation of methylene blue (MB) all present a V-shape with different radiation power ratios. However, through the comparison of photocatalytic activities of Au/TiO2 and CdS/Au/TiO2 by statistics and mathematical simulation, we propose qualitatively that the deposition of CdS used as a photosensitizer could extend the Au/TiO2 light absorption range and weaken the negative effect of Au/TiO2. Compared with Au/TiO2, it is proven indirectly that the photo-excited electrons of CdS/Au/TiO2 transfer from CdS to Au, and then to TiO2. Furthermore, we discuss the photocatalytic dual opposite roles of Au nanoparticles between CdS and TiO2, the positive effect includes localized surface plasmon resonance (LSPR) and Schottky barrier (SB), and the...
A high-performance α-MoO3/multiwalled carbon nanotube (MWCNT) nanocomposite material is synthesiz... more A high-performance α-MoO3/multiwalled carbon nanotube (MWCNT) nanocomposite material is synthesized via a novel surfactant-assisted solvothermal process followed by low-temperature calcination. Its structure, composition, and morphology are characterized by X-ray diffraction, X-ray photoelectron spectroscopy, energy-dispersive X-ray spectroscopy, carbon element analysis, nitrogen adsorption-desorption determination, scanning electron microscopy, and transmission electron microscopy techniques. Its electrochemical performance as a high-capacity lithium-ion-battery anode material is investigated by cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic discharge/recharge methods. This composite material exhibits not only high capacity but also excellent rate capability and cyclability. For example, when the discharge/charge current density is increased from 0.1 to 2 A g(-1), the reversible charge capacity is only decreased from 1138.3 to 941.4 mAh g(-1), giving ...
... Jiaqiang Xu a , Corresponding Author Contact Information , Qingyi Pan b , Yu'an ... more ... Jiaqiang Xu a , Corresponding Author Contact Information , Qingyi Pan b , Yu'an Shun a and Zhizhuang Tian a. ... But its particle size distribution is not homogeneous [4]. In this paper, the sensors made by microemulsion with surfactants show good application prospects. ...
Mesoporous SnO 2 is obtained through a simple hydrothermal process by using tin chloride as a raw... more Mesoporous SnO 2 is obtained through a simple hydrothermal process by using tin chloride as a raw material, urea as a pore-forming agent and pH regulator. X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET) nitrogen adsorption-desorption measurements are employed to characterize the obtained mesoporous structures. The results show that the as synthesized material after calcination can be well indexed to tetragonal phase SnO 2 with a mesoporous structure. The sensing properties of the sensor based on mesoporous SnO 2 are investigated. The results reveal that the response to dilute Cl 2 gas of the materials is very high and fast. The short recovery time mainly attributes to the bigger pore size of mesoporous SnO 2 . Finally, the reaction mechanism is proposed.
Semiconductor metal oxides as gas sensing materials have been extensively studied for a long time... more Semiconductor metal oxides as gas sensing materials have been extensively studied for a long time due to their advantageous features, such as good sensitivity to the ambient conditions and simplicity in fabrication [1], [2] and [3]. Nevertheless, there are still some critical limitations ...
Nanosized ZnO powder was synthesized by using a chemical precipitation method, and loaded with di... more Nanosized ZnO powder was synthesized by using a chemical precipitation method, and loaded with different dopants through impregnation. The as-prepared ZnO powder was characterized by XRD and TEM. The characterization results show that the as-prepared sample is wurtzite polycrystalline ZnO, the mean grain size is 30-40 nm, and there are three types of adsorbed oxygen (O 2 − , O 2 2− , and O 2− ) on the surface of the sample. The as-prepared ZnO powder shows excellent gas responses to alcohol and acetaldehyde, but no response to ethene. The sensing mechanism of ZnO was further studied with the help of gas chromatography (GC) associated with a fixed-bed reactor. The studies show that acetaldehyde, carbon dioxide and water are the only oxidation products of C 2 H 5 OH over ZnO. The gas response to C 2 H 5 OH is strongly dependent on the conversion ratio of C 2 H 5 OH to acetaldehyde. In addition, among all the dopants tested, Ru is the optimal dopant which can increase the response to C 2 H 5 OH, but cannot increase the conversion ratio of C 2 H 5 OH to acetaldehyde. Thus we suggest that the gas sensing mechanism of ZnO to C 2 H 5 OH is the mode controlled by chemisorption of negatively charged oxygen, and the sensitizing role of Ru in the ZnO sensor belongs to the electronic sensitization mechanism.
Hierarchical porous wood-templated ZnO has been successfully synthesized using Lauan and Fir wood... more Hierarchical porous wood-templated ZnO has been successfully synthesized using Lauan and Fir woods as template through a simple hydrothermal bioinspired approach. The template type and calcination temperature in the preparation process have a large effect on the morphologies and porous structures of ZnO according to FESEM, TEM, mercury porosimetry and N 2 adsorption investigations. The gas sensing performances of wood-templated and non-templated ZnO were investigated using H 2 , CO, H 2 S, NH 3 , Formaldehyde, Methanol, Ethanol, Acetone, and Isobutene. The article studies the effects of wood template, calcination temperature, and working temperature of gas flow on the gas sensitivity and selectivity in detail. It is revealed that wood-templated ZnO has excellent sensitivity and selectivity to H 2 S due to inheritance of wood's hierarchical porous structure. The sensing response to H 2 S of Fir-templated ZnO is about 5.1 times higher than that of non-templated ZnO. Fir-templated ZnO calcined at 600 • C, has the best sensing properties including the highest gas sensing response, the highest selectivity coefficients of H 2 S and the shortest response and recovery time. The selective sensing mechanism has been discussed from some key aspects, such as gas properties, gas-solid reactions, grain size and hierarchical porous microstructures.
A simple and green technique has been developed to prepare hierarchical biomorphic ZnO, using egg... more A simple and green technique has been developed to prepare hierarchical biomorphic ZnO, using eggshell membrane (ESM) as the template. ESM was infiltrated with zinc nitrate solution and subsequently sintered at high temperatures to produce the final ZnO ...
The nanometer-size In 2 O 3 was synthesized via a reverse microemulsion. A new catalytic combusti... more The nanometer-size In 2 O 3 was synthesized via a reverse microemulsion. A new catalytic combustion-type In 2 O 3 -based H 2 gas sensor was developed based on the technology for fabricating the direct-heating-type sensor and a surface-modifying process. A dense SiO 2 layer near the surface of the sensor was formed by chemical vapor deposition (CVD) of hexamethyldisiloxane (HMDS). The SiO 2 layer, which acted as a molecular sieve, reduced the penetration of large molecular, such as C 2 H 5 OH, CH 4 , i-C 4 H 10 , into the sensing layer, resulting in the improvement of selectivity to H 2 . The sensitive properties and the working mechanism of the sensor were presented. The In 2 O 3 nanoparticles prepared by microemulsion were characterized by transmission electron microscopy and X-ray diffraction.
XU JIAQIANG∗ College of Materials and Chemical Engineering, Zhengzhou University of Light Industr... more XU JIAQIANG∗ College of Materials and Chemical Engineering, Zhengzhou University of Light Industry, He'nan, Zhengzhou 450002, People's Republic of China; Institute of Materials, Shanghai University, Shanghai 200072, People's Republic of China E-mail: [email protected]
The nanocomposite with polypyrrole (PPy) confined in ordered mesoporous silica SBA-15 channels wa... more The nanocomposite with polypyrrole (PPy) confined in ordered mesoporous silica SBA-15 channels was synthesized by in situ electropolymerization. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, N 2 adsorption/desorption, and FT-IR studies indicated that the nanocomposite has the well-ordered hexagonal structures and PPy was in situ polymerized into the channels instead of the outer surface of SBA-15. Furthermore, the PPy/SBA-15 nanocomposite was used as an electrode modifier. We found that the nanocomposite-modified electrode exhibited good electrocatalytic activities for hydroquinone oxidation where PPy chains could facilitate the electron transfer between molecular sieves and electrode surface. Three dihydroxybenzene isomers (hydroquinone, catechol and resorcinol) have been successfully detected at PPy/SBA-15 modified electrode by preconcentration of the analyte.
Physical chemistry chemical physics : PCCP, Jan 12, 2016
Herein, we demonstrate experimentally the coexistence of photocatalytic dual opposite roles of Au... more Herein, we demonstrate experimentally the coexistence of photocatalytic dual opposite roles of Au nanoparticles in a UV-vis light irradiated Au/TiO2 system. We have investigated that the photocatalytic performance curves of Au/TiO2 and CdS/Au/TiO2 for degradation of methylene blue (MB) all present a V-shape with different radiation power ratios. However, through the comparison of photocatalytic activities of Au/TiO2 and CdS/Au/TiO2 by statistics and mathematical simulation, we propose qualitatively that the deposition of CdS used as a photosensitizer could extend the Au/TiO2 light absorption range and weaken the negative effect of Au/TiO2. Compared with Au/TiO2, it is proven indirectly that the photo-excited electrons of CdS/Au/TiO2 transfer from CdS to Au, and then to TiO2. Furthermore, we discuss the photocatalytic dual opposite roles of Au nanoparticles between CdS and TiO2, the positive effect includes localized surface plasmon resonance (LSPR) and Schottky barrier (SB), and the...
A high-performance α-MoO3/multiwalled carbon nanotube (MWCNT) nanocomposite material is synthesiz... more A high-performance α-MoO3/multiwalled carbon nanotube (MWCNT) nanocomposite material is synthesized via a novel surfactant-assisted solvothermal process followed by low-temperature calcination. Its structure, composition, and morphology are characterized by X-ray diffraction, X-ray photoelectron spectroscopy, energy-dispersive X-ray spectroscopy, carbon element analysis, nitrogen adsorption-desorption determination, scanning electron microscopy, and transmission electron microscopy techniques. Its electrochemical performance as a high-capacity lithium-ion-battery anode material is investigated by cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic discharge/recharge methods. This composite material exhibits not only high capacity but also excellent rate capability and cyclability. For example, when the discharge/charge current density is increased from 0.1 to 2 A g(-1), the reversible charge capacity is only decreased from 1138.3 to 941.4 mAh g(-1), giving ...
... Jiaqiang Xu a , Corresponding Author Contact Information , Qingyi Pan b , Yu'an ... more ... Jiaqiang Xu a , Corresponding Author Contact Information , Qingyi Pan b , Yu'an Shun a and Zhizhuang Tian a. ... But its particle size distribution is not homogeneous [4]. In this paper, the sensors made by microemulsion with surfactants show good application prospects. ...
Mesoporous SnO 2 is obtained through a simple hydrothermal process by using tin chloride as a raw... more Mesoporous SnO 2 is obtained through a simple hydrothermal process by using tin chloride as a raw material, urea as a pore-forming agent and pH regulator. X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett-Teller (BET) nitrogen adsorption-desorption measurements are employed to characterize the obtained mesoporous structures. The results show that the as synthesized material after calcination can be well indexed to tetragonal phase SnO 2 with a mesoporous structure. The sensing properties of the sensor based on mesoporous SnO 2 are investigated. The results reveal that the response to dilute Cl 2 gas of the materials is very high and fast. The short recovery time mainly attributes to the bigger pore size of mesoporous SnO 2 . Finally, the reaction mechanism is proposed.
Semiconductor metal oxides as gas sensing materials have been extensively studied for a long time... more Semiconductor metal oxides as gas sensing materials have been extensively studied for a long time due to their advantageous features, such as good sensitivity to the ambient conditions and simplicity in fabrication [1], [2] and [3]. Nevertheless, there are still some critical limitations ...
Nanosized ZnO powder was synthesized by using a chemical precipitation method, and loaded with di... more Nanosized ZnO powder was synthesized by using a chemical precipitation method, and loaded with different dopants through impregnation. The as-prepared ZnO powder was characterized by XRD and TEM. The characterization results show that the as-prepared sample is wurtzite polycrystalline ZnO, the mean grain size is 30-40 nm, and there are three types of adsorbed oxygen (O 2 − , O 2 2− , and O 2− ) on the surface of the sample. The as-prepared ZnO powder shows excellent gas responses to alcohol and acetaldehyde, but no response to ethene. The sensing mechanism of ZnO was further studied with the help of gas chromatography (GC) associated with a fixed-bed reactor. The studies show that acetaldehyde, carbon dioxide and water are the only oxidation products of C 2 H 5 OH over ZnO. The gas response to C 2 H 5 OH is strongly dependent on the conversion ratio of C 2 H 5 OH to acetaldehyde. In addition, among all the dopants tested, Ru is the optimal dopant which can increase the response to C 2 H 5 OH, but cannot increase the conversion ratio of C 2 H 5 OH to acetaldehyde. Thus we suggest that the gas sensing mechanism of ZnO to C 2 H 5 OH is the mode controlled by chemisorption of negatively charged oxygen, and the sensitizing role of Ru in the ZnO sensor belongs to the electronic sensitization mechanism.
Hierarchical porous wood-templated ZnO has been successfully synthesized using Lauan and Fir wood... more Hierarchical porous wood-templated ZnO has been successfully synthesized using Lauan and Fir woods as template through a simple hydrothermal bioinspired approach. The template type and calcination temperature in the preparation process have a large effect on the morphologies and porous structures of ZnO according to FESEM, TEM, mercury porosimetry and N 2 adsorption investigations. The gas sensing performances of wood-templated and non-templated ZnO were investigated using H 2 , CO, H 2 S, NH 3 , Formaldehyde, Methanol, Ethanol, Acetone, and Isobutene. The article studies the effects of wood template, calcination temperature, and working temperature of gas flow on the gas sensitivity and selectivity in detail. It is revealed that wood-templated ZnO has excellent sensitivity and selectivity to H 2 S due to inheritance of wood's hierarchical porous structure. The sensing response to H 2 S of Fir-templated ZnO is about 5.1 times higher than that of non-templated ZnO. Fir-templated ZnO calcined at 600 • C, has the best sensing properties including the highest gas sensing response, the highest selectivity coefficients of H 2 S and the shortest response and recovery time. The selective sensing mechanism has been discussed from some key aspects, such as gas properties, gas-solid reactions, grain size and hierarchical porous microstructures.
A simple and green technique has been developed to prepare hierarchical biomorphic ZnO, using egg... more A simple and green technique has been developed to prepare hierarchical biomorphic ZnO, using eggshell membrane (ESM) as the template. ESM was infiltrated with zinc nitrate solution and subsequently sintered at high temperatures to produce the final ZnO ...
The nanometer-size In 2 O 3 was synthesized via a reverse microemulsion. A new catalytic combusti... more The nanometer-size In 2 O 3 was synthesized via a reverse microemulsion. A new catalytic combustion-type In 2 O 3 -based H 2 gas sensor was developed based on the technology for fabricating the direct-heating-type sensor and a surface-modifying process. A dense SiO 2 layer near the surface of the sensor was formed by chemical vapor deposition (CVD) of hexamethyldisiloxane (HMDS). The SiO 2 layer, which acted as a molecular sieve, reduced the penetration of large molecular, such as C 2 H 5 OH, CH 4 , i-C 4 H 10 , into the sensing layer, resulting in the improvement of selectivity to H 2 . The sensitive properties and the working mechanism of the sensor were presented. The In 2 O 3 nanoparticles prepared by microemulsion were characterized by transmission electron microscopy and X-ray diffraction.
XU JIAQIANG∗ College of Materials and Chemical Engineering, Zhengzhou University of Light Industr... more XU JIAQIANG∗ College of Materials and Chemical Engineering, Zhengzhou University of Light Industry, He'nan, Zhengzhou 450002, People's Republic of China; Institute of Materials, Shanghai University, Shanghai 200072, People's Republic of China E-mail: [email protected]
The nanocomposite with polypyrrole (PPy) confined in ordered mesoporous silica SBA-15 channels wa... more The nanocomposite with polypyrrole (PPy) confined in ordered mesoporous silica SBA-15 channels was synthesized by in situ electropolymerization. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, N 2 adsorption/desorption, and FT-IR studies indicated that the nanocomposite has the well-ordered hexagonal structures and PPy was in situ polymerized into the channels instead of the outer surface of SBA-15. Furthermore, the PPy/SBA-15 nanocomposite was used as an electrode modifier. We found that the nanocomposite-modified electrode exhibited good electrocatalytic activities for hydroquinone oxidation where PPy chains could facilitate the electron transfer between molecular sieves and electrode surface. Three dihydroxybenzene isomers (hydroquinone, catechol and resorcinol) have been successfully detected at PPy/SBA-15 modified electrode by preconcentration of the analyte.
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