A simple one-step thermal pyrolysis route has been developed to prepare carbon membrane from a na... more A simple one-step thermal pyrolysis route has been developed to prepare carbon membrane from a natural leaf. The carbonized leaf membrane possesses anisotropic surfaces and internal hierarchical porosity, exhibiting a high specific capacity of 360 mAh/g and a high initial Columbic efficiency of 74.8% as a binder-free, current collector-free anode for rechargeable sodium-ion batteries. Moreover, large area carbon membranes with low contact resistance are fabricated by simply stacking and carbonizing leaves, a promising strategy toward large-scale sodium-ion battery developments.
New model catalysts are important for studying the interface interaction and their influence on t... more New model catalysts are important for studying the interface interaction and their influence on the catalytic performance. In this paper, a novel Ag/C 60 nanocomposite catalyst (Ag/C 60 NCC) has been designed, prepared, and applied for the first time in the hydrogenation of aromatic nitro compounds. A new band at 1100 cm -1 appears in the Fourier transform infrared (FTIR) spectra of the Ag/C 60 NCC, and the peak of the A g (2) mode of C 60 shifts clearly from 1468 to 1464 cm -1 in the Raman spectrum. X-ray photoelectron (XPS) spectrum of Ag 3d electron can be curve fitted into two pairs of peaks, corresponding to neutral Ag and Ag + , and the half-peak breadth is also broadened. Ag/C 60 NCC exhibits excellent activity and selectivity in the hydrogenation of chloronitrobenzenes and nitrobenzaldehydes, whereas Ag nanocrystals (NCs), the mixture of Ag NCs, and C 60 NCs do worse. These results evidence the presence of the charge transfer from Ag to C 60 and clearly indicate the catalytic performance's dependence on the interface interaction between Ag NCs and support C 60 NCs.
ABSTRACT The research on the heterogeneous catalytic synthesis of tetrazoles has attracted great ... more ABSTRACT The research on the heterogeneous catalytic synthesis of tetrazoles has attracted great attention. In this paper, a tungsten atom-containing AlPO-5 microporous molecular sieve (termed as WAlPO-5) was designed and synthesized by the incorporation of tungsten atoms into the AlPO-5 skeleton with triethylamine as a structure template from pseudoboehmite, H3PO4 and tungstophosphoric acid. The incorporation of tungsten atoms into the AlPO-5 skeleton has been demonstrated by systematic characterizations. WAlPO-5 can be used as an efficient heterogeneous catalyst for the synthesis of 5-substituted 1H-tetrazoles by [3+2] cycloaddition from nitriles and sodium azide. As a novel heterogeneous catalyst, WAlPO-5 exhibits a high catalytic activity, a superior cycling stability and an excellent substrate applicability. The significant advantages of WAlPO-5, such as the simple procedure and the mild reaction conditions and as an alternative to those corrosive, hazardous and polluting homogeneous catalysts, warrant its potential application in industrial processes.
We have developed a method of controllable synthesis of MgO with various morphologies by adjustin... more We have developed a method of controllable synthesis of MgO with various morphologies by adjusting the composition and phase structure of magnesium carbonate hydrate (MCH). The phase structure of the MCH varied from monoclinic Mg 5 (CO 3 ) 4 (OH) 2 (H 2 O) 4 to hexagonal MgCO 3 by changing the concentration of Mg 2+ and HCO 3 -; the corresponding morphology of the MCH ranges from nanoflakes and flowerlike microspheres composed of nanoflakes to layer-like rhombohedra and microspheres composed of rhombohedra. After annealing, four kinds of mesoporous cubic MgO micronano structures were obtained with their original morphologies. Because of the high specific surface area, MgO mesoporous nanoflakes and flowerlike microsphers exhibited excellent absorption performance for common toxic heavy metal ions and organic pollutants and are expected to be a potential absorbent in wastewater treatment.
The oxidation-resistant acidic resins are of great importance for the catalytic oxidation systems... more The oxidation-resistant acidic resins are of great importance for the catalytic oxidation systems. In this paper, the oxidatively stable acidic resins are obtained from the cation ion exchange resins (CIERs) through the thermal treatment in N(2) atmosphere. The structure and properties of the thermally treated CIERs were characterized by chemical analysis, Fourier transform infrared (FT-IR) spectra, acid capacity measurement and scanning electron microscope (SEM). The thermally treated CIERs possess high acid capacity up to 4.09 mmol g(-1). A partial carbonization is observed in the thermal treatment process of CIERs, but the morphology of resin spheres maintains well. The as-prepared CIERs are used as solid acids to assist the hydrogen peroxide oxidation of cyclohexene to adipic acid (ADA) with tungstic acid as the catalyst precursor. The improved yields of ADA in the recycling reaction are obtained in the presence of acidic CIERs. Meanwhile, the unproductive decomposition of H(2)O(2) is effectively suppressed. The high yields of ADA (about 81%) are kept by the thermally treated CIERs even after the fifth cycle. The thermally treated CIERs exhibit excellent acid-catalytic performance and possess remarkable oxidation-resistant capability.
In this article, TiO(2)-Carbon-rGO (GCT) three-component composite material has been constructed ... more In this article, TiO(2)-Carbon-rGO (GCT) three-component composite material has been constructed by anchoring TiO(2) nanoparticles (NPs) encapsulated in carbon shells onto reduced graphene oxide (rGO) sheets. The structure of GCT was characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), N(2) adsorption-desorption isotherms, and transmission electron microscopy (TEM). This material shows a superior retention as the anode materials in lithium ion battery with a specific discharge capacity of 188 mA h g(-1) in the initial cycle and 158 mA h g(-1) after 100 cycles.
ABSTRACT Controlled synthesis of hierarchically assembled titanium dioxide (TiO2) nanostructures ... more ABSTRACT Controlled synthesis of hierarchically assembled titanium dioxide (TiO2) nanostructures is important for practical applications in environmental purification and solar energy conversion. We present here the fabrication of interconnected TiO2 nanotubes as a macroscopic bulk material by using a porous carbon nanotube (CNT) sponge as a template. The basic idea is to uniformly coat an amorphous titania layer onto the CNT surface by the infiltration of a TiO2 precursor into the sponge followed by a subsequent hydrolysis process. After calcination, the CNTs are completely removed and the titania is simultaneously crystallized, which results in a porous macrostructure composed of interconnected anatase TiO2 nanotubes. The TiO2 nanotube macrostructures show comparable photocatalytic activities to commercial products (AEROXIDE TiO2 P25) for the degradation of rhodamine B (RhB). Moreover, the TiO2 nanotube macrostructures can be settled and separated from water within 12 h after photocatalysis, whereas P25 remains suspended in solution after weeks. Thus the TiO2 nanotube macrostructures offer the advantage of easy catalyst separation and recycle and can be a promising candidate for wastewater treatment.
Advanced materials (Deerfield Beach, Fla.), Jan 26, 2014
Carbon nanotube sponges and aligned arrays are seamlessly integrated into numerous possible confi... more Carbon nanotube sponges and aligned arrays are seamlessly integrated into numerous possible configurations such as series, parallel, package, and sandwich complex structures, leading to significantly broadened stress plateau and enhanced energy dissipation.
A unique cage growth of graphene is developed by using carbon nanotube (CNT) spider webs as porou... more A unique cage growth of graphene is developed by using carbon nanotube (CNT) spider webs as porous templates, resulting in CNT/graphene hybrids with high conductivity and mechanical flexibility. Furthermore, monolithic all-carbon transistors with graphene as active elements and CNT/graphene hybrids as contacts and interconnects are directly formed by chemical synthesis, and flexible all-carbon bioelectronics are subsequently demonstrated for in vivo mapping of cardiac signals.
Chemical communications (Cambridge, England), Jan 14, 2010
Carbon nanotube sponges show effective filtration for nanoparticles and dye molecules with differ... more Carbon nanotube sponges show effective filtration for nanoparticles and dye molecules with different sizes and concentrations from water. The three-dimensional interconnected porous structure formed by entangled nanotubes can trap nanoparticles and molecules by physisorption without the need for chemical functionalization. The sponge filters are potential environmental materials for water treatment.
We have combined two planar nanostructures, graphene and CdSe nanobelts, to construct Schottky ju... more We have combined two planar nanostructures, graphene and CdSe nanobelts, to construct Schottky junction solar cells with open-circuit voltages of about 0.5 V and cell efficiencies on the order of 0.1%. By covering transparent graphene or carbon nanotube (CNT) films on selected positions along macroscopically long CdSe nanobelts, we have demonstrated the fabrication of active solar cells with many different configurations and parallel connections from individual or multiple assembled nanobelts. The graphene-CdSe nanobelt solar cells reported here show a great flexibility in creating diverse device architectures, and might be scaled up for cell integration based on assembled nanobelt arrays and patterned graphene (or CNT) films.
Semiconducting nanoparticles with lower bandgap (e.g., CdS) are alternative photocatalysts to TiO... more Semiconducting nanoparticles with lower bandgap (e.g., CdS) are alternative photocatalysts to TiO 2 , since they have a potentially wider range light of absorption and improved catalytic efficiency. However, they must be securely anchored on a porous substrate for practical applications. Here, we report a hybrid porous photocatalyst fabricated by grafting 4-6 nm diameter CdS nanoparticles uniformly throughout the entire macroporous structure of a three-dimensional carbon nanotube (CNT) sponge. The unique feature of our structure is that only the CdS nanoparticles grafted on the outside surface are active in photocatalysis, while other nanoparticles are stored inside the sponge in the fresh state for use when the catalyst is recycled. Our CdS-CNT hybrid sponges show high efficiency in removing organic contaminants from water. Spectroscopic measurements show that the hybrid sponges are multifunctional, simultaneously performing organic molecular adsorption (using the inter-CNT spacing), and photocatalytic decomposition (by the CdS nanoparticles grafted on the surface), both of which contribute to water purification. Furthermore, the surface part of the sponges can be stripped off to expose inner nanoparticles for use when the catalyst is recycled, without performance degradation.
A simple one-step thermal pyrolysis route has been developed to prepare carbon membrane from a na... more A simple one-step thermal pyrolysis route has been developed to prepare carbon membrane from a natural leaf. The carbonized leaf membrane possesses anisotropic surfaces and internal hierarchical porosity, exhibiting a high specific capacity of 360 mAh/g and a high initial Columbic efficiency of 74.8% as a binder-free, current collector-free anode for rechargeable sodium-ion batteries. Moreover, large area carbon membranes with low contact resistance are fabricated by simply stacking and carbonizing leaves, a promising strategy toward large-scale sodium-ion battery developments.
New model catalysts are important for studying the interface interaction and their influence on t... more New model catalysts are important for studying the interface interaction and their influence on the catalytic performance. In this paper, a novel Ag/C 60 nanocomposite catalyst (Ag/C 60 NCC) has been designed, prepared, and applied for the first time in the hydrogenation of aromatic nitro compounds. A new band at 1100 cm -1 appears in the Fourier transform infrared (FTIR) spectra of the Ag/C 60 NCC, and the peak of the A g (2) mode of C 60 shifts clearly from 1468 to 1464 cm -1 in the Raman spectrum. X-ray photoelectron (XPS) spectrum of Ag 3d electron can be curve fitted into two pairs of peaks, corresponding to neutral Ag and Ag + , and the half-peak breadth is also broadened. Ag/C 60 NCC exhibits excellent activity and selectivity in the hydrogenation of chloronitrobenzenes and nitrobenzaldehydes, whereas Ag nanocrystals (NCs), the mixture of Ag NCs, and C 60 NCs do worse. These results evidence the presence of the charge transfer from Ag to C 60 and clearly indicate the catalytic performance's dependence on the interface interaction between Ag NCs and support C 60 NCs.
ABSTRACT The research on the heterogeneous catalytic synthesis of tetrazoles has attracted great ... more ABSTRACT The research on the heterogeneous catalytic synthesis of tetrazoles has attracted great attention. In this paper, a tungsten atom-containing AlPO-5 microporous molecular sieve (termed as WAlPO-5) was designed and synthesized by the incorporation of tungsten atoms into the AlPO-5 skeleton with triethylamine as a structure template from pseudoboehmite, H3PO4 and tungstophosphoric acid. The incorporation of tungsten atoms into the AlPO-5 skeleton has been demonstrated by systematic characterizations. WAlPO-5 can be used as an efficient heterogeneous catalyst for the synthesis of 5-substituted 1H-tetrazoles by [3+2] cycloaddition from nitriles and sodium azide. As a novel heterogeneous catalyst, WAlPO-5 exhibits a high catalytic activity, a superior cycling stability and an excellent substrate applicability. The significant advantages of WAlPO-5, such as the simple procedure and the mild reaction conditions and as an alternative to those corrosive, hazardous and polluting homogeneous catalysts, warrant its potential application in industrial processes.
We have developed a method of controllable synthesis of MgO with various morphologies by adjustin... more We have developed a method of controllable synthesis of MgO with various morphologies by adjusting the composition and phase structure of magnesium carbonate hydrate (MCH). The phase structure of the MCH varied from monoclinic Mg 5 (CO 3 ) 4 (OH) 2 (H 2 O) 4 to hexagonal MgCO 3 by changing the concentration of Mg 2+ and HCO 3 -; the corresponding morphology of the MCH ranges from nanoflakes and flowerlike microspheres composed of nanoflakes to layer-like rhombohedra and microspheres composed of rhombohedra. After annealing, four kinds of mesoporous cubic MgO micronano structures were obtained with their original morphologies. Because of the high specific surface area, MgO mesoporous nanoflakes and flowerlike microsphers exhibited excellent absorption performance for common toxic heavy metal ions and organic pollutants and are expected to be a potential absorbent in wastewater treatment.
The oxidation-resistant acidic resins are of great importance for the catalytic oxidation systems... more The oxidation-resistant acidic resins are of great importance for the catalytic oxidation systems. In this paper, the oxidatively stable acidic resins are obtained from the cation ion exchange resins (CIERs) through the thermal treatment in N(2) atmosphere. The structure and properties of the thermally treated CIERs were characterized by chemical analysis, Fourier transform infrared (FT-IR) spectra, acid capacity measurement and scanning electron microscope (SEM). The thermally treated CIERs possess high acid capacity up to 4.09 mmol g(-1). A partial carbonization is observed in the thermal treatment process of CIERs, but the morphology of resin spheres maintains well. The as-prepared CIERs are used as solid acids to assist the hydrogen peroxide oxidation of cyclohexene to adipic acid (ADA) with tungstic acid as the catalyst precursor. The improved yields of ADA in the recycling reaction are obtained in the presence of acidic CIERs. Meanwhile, the unproductive decomposition of H(2)O(2) is effectively suppressed. The high yields of ADA (about 81%) are kept by the thermally treated CIERs even after the fifth cycle. The thermally treated CIERs exhibit excellent acid-catalytic performance and possess remarkable oxidation-resistant capability.
In this article, TiO(2)-Carbon-rGO (GCT) three-component composite material has been constructed ... more In this article, TiO(2)-Carbon-rGO (GCT) three-component composite material has been constructed by anchoring TiO(2) nanoparticles (NPs) encapsulated in carbon shells onto reduced graphene oxide (rGO) sheets. The structure of GCT was characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), N(2) adsorption-desorption isotherms, and transmission electron microscopy (TEM). This material shows a superior retention as the anode materials in lithium ion battery with a specific discharge capacity of 188 mA h g(-1) in the initial cycle and 158 mA h g(-1) after 100 cycles.
ABSTRACT Controlled synthesis of hierarchically assembled titanium dioxide (TiO2) nanostructures ... more ABSTRACT Controlled synthesis of hierarchically assembled titanium dioxide (TiO2) nanostructures is important for practical applications in environmental purification and solar energy conversion. We present here the fabrication of interconnected TiO2 nanotubes as a macroscopic bulk material by using a porous carbon nanotube (CNT) sponge as a template. The basic idea is to uniformly coat an amorphous titania layer onto the CNT surface by the infiltration of a TiO2 precursor into the sponge followed by a subsequent hydrolysis process. After calcination, the CNTs are completely removed and the titania is simultaneously crystallized, which results in a porous macrostructure composed of interconnected anatase TiO2 nanotubes. The TiO2 nanotube macrostructures show comparable photocatalytic activities to commercial products (AEROXIDE TiO2 P25) for the degradation of rhodamine B (RhB). Moreover, the TiO2 nanotube macrostructures can be settled and separated from water within 12 h after photocatalysis, whereas P25 remains suspended in solution after weeks. Thus the TiO2 nanotube macrostructures offer the advantage of easy catalyst separation and recycle and can be a promising candidate for wastewater treatment.
Advanced materials (Deerfield Beach, Fla.), Jan 26, 2014
Carbon nanotube sponges and aligned arrays are seamlessly integrated into numerous possible confi... more Carbon nanotube sponges and aligned arrays are seamlessly integrated into numerous possible configurations such as series, parallel, package, and sandwich complex structures, leading to significantly broadened stress plateau and enhanced energy dissipation.
A unique cage growth of graphene is developed by using carbon nanotube (CNT) spider webs as porou... more A unique cage growth of graphene is developed by using carbon nanotube (CNT) spider webs as porous templates, resulting in CNT/graphene hybrids with high conductivity and mechanical flexibility. Furthermore, monolithic all-carbon transistors with graphene as active elements and CNT/graphene hybrids as contacts and interconnects are directly formed by chemical synthesis, and flexible all-carbon bioelectronics are subsequently demonstrated for in vivo mapping of cardiac signals.
Chemical communications (Cambridge, England), Jan 14, 2010
Carbon nanotube sponges show effective filtration for nanoparticles and dye molecules with differ... more Carbon nanotube sponges show effective filtration for nanoparticles and dye molecules with different sizes and concentrations from water. The three-dimensional interconnected porous structure formed by entangled nanotubes can trap nanoparticles and molecules by physisorption without the need for chemical functionalization. The sponge filters are potential environmental materials for water treatment.
We have combined two planar nanostructures, graphene and CdSe nanobelts, to construct Schottky ju... more We have combined two planar nanostructures, graphene and CdSe nanobelts, to construct Schottky junction solar cells with open-circuit voltages of about 0.5 V and cell efficiencies on the order of 0.1%. By covering transparent graphene or carbon nanotube (CNT) films on selected positions along macroscopically long CdSe nanobelts, we have demonstrated the fabrication of active solar cells with many different configurations and parallel connections from individual or multiple assembled nanobelts. The graphene-CdSe nanobelt solar cells reported here show a great flexibility in creating diverse device architectures, and might be scaled up for cell integration based on assembled nanobelt arrays and patterned graphene (or CNT) films.
Semiconducting nanoparticles with lower bandgap (e.g., CdS) are alternative photocatalysts to TiO... more Semiconducting nanoparticles with lower bandgap (e.g., CdS) are alternative photocatalysts to TiO 2 , since they have a potentially wider range light of absorption and improved catalytic efficiency. However, they must be securely anchored on a porous substrate for practical applications. Here, we report a hybrid porous photocatalyst fabricated by grafting 4-6 nm diameter CdS nanoparticles uniformly throughout the entire macroporous structure of a three-dimensional carbon nanotube (CNT) sponge. The unique feature of our structure is that only the CdS nanoparticles grafted on the outside surface are active in photocatalysis, while other nanoparticles are stored inside the sponge in the fresh state for use when the catalyst is recycled. Our CdS-CNT hybrid sponges show high efficiency in removing organic contaminants from water. Spectroscopic measurements show that the hybrid sponges are multifunctional, simultaneously performing organic molecular adsorption (using the inter-CNT spacing), and photocatalytic decomposition (by the CdS nanoparticles grafted on the surface), both of which contribute to water purification. Furthermore, the surface part of the sponges can be stripped off to expose inner nanoparticles for use when the catalyst is recycled, without performance degradation.
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Papers by Hongbian Li