In this work, ultra-large sheet NiAl-layered double hydroxide(LDH)/reduced graphene oxide(RGO) nanocomposites were facilely synthesized via in situ growth of NiAl-LDH on a graphene surface without any surfactant or te...In this work, ultra-large sheet NiAl-layered double hydroxide(LDH)/reduced graphene oxide(RGO) nanocomposites were facilely synthesized via in situ growth of NiAl-LDH on a graphene surface without any surfactant or template. It was found that with a microwave-assisted method, NiAl-LDH nanosheets grew evenly on the surface of graphene. With this method, the formation of NiAl-LDH and reduction of graphene oxide were achieved in one step. The unique structure endows the electrode materials with a higher specific surface area, which is favorable for enhancing the capacity performance. The morphology and microstructure of the as-prepared composites were characterized by X-ray diffraction, Brunauer-EmmettTeller surface area measurement, and transmission electron microscopy. The specific surface area and pore volume of the RGO/LDH composite are 108.3 m^2 g^(-1) and 0.74 cm^3 g^(-1), respectively, which are much larger than those of pure LDHs(19.8 m^2 g^(-1) and 0.065 cm^3 g(-1), respectively). The capacitive properties of the synthesized electrodes were studied using cyclic voltammetry and electrochemical impedance spectroscopy in a three-electrode experimental setup. The specific capacitance of RGO/LDHs was calculated to be 1055 F g^(-1) at 1 Ag^(-1). It could be anticipated that the synthesized electrodes will find promising applications as novel electrode materials in supercapacitors and other devices because of their outstanding characteristics of controllable capacitance and facile synthesis.展开更多
This review covers the major reactions involved in the solution synthesis of nanomaterials.It was designed to classify the traditional strategies such as precipitation,reduction,seed growth,etching,and so on into two ...This review covers the major reactions involved in the solution synthesis of nanomaterials.It was designed to classify the traditional strategies such as precipitation,reduction,seed growth,etching,and so on into two basic processes which are termed as bottom-up and top-down routines.The discussion is focused on the basic mechanism and principles during the nudeation and growth of nanocrystals,especially in the solution system.This review also presents a prediction for how to utilize these intrinsic processes to artificially construct the desired specific and functional nanostructures.We try to describe the most directive and effective way to control the structures of nanocrystals for researchers who can master the major reaction mechanism and grasp the basic technologies in synthetic nanoscience.展开更多
A novel one-pot approach to synthesize the tiara-like Pd(II) thiolate complex compound, [Pd(SCH_3)_2]_6, was developed. In this strategy, dimethyl sulfoxide(DMSO) was used as a thiolate source instead of methyl mercap...A novel one-pot approach to synthesize the tiara-like Pd(II) thiolate complex compound, [Pd(SCH_3)_2]_6, was developed. In this strategy, dimethyl sulfoxide(DMSO) was used as a thiolate source instead of methyl mercaptan(CH_3SH). DMSO was first decomposed into CH_3SH and formaldehyde(HCHO); then, the in situ as-formed CH_3SH molecules reacted with palladium acetate, and formed [Pd(SCH_3)_2]_6. By tuning the reaction condition, the morphology of the [Pd(SCH_3)_2]_6 assemblies can change from microprism to nanosphere. The characterization of the pyrolysis product demonstrated that these two kinds of [Pd(SCH_3)_2]_6 assemblies with different shapes could further decompose into palladium or palladium sulfides through different pyrolysis conditions.展开更多
Tremendous efforts have been devoted to explore energy-efficient strategies of ammonia synthesis to replace Haber-Bosch process which accounts for 1.4% of the annual energy consumption. In this study, atomically dispe...Tremendous efforts have been devoted to explore energy-efficient strategies of ammonia synthesis to replace Haber-Bosch process which accounts for 1.4% of the annual energy consumption. In this study, atomically dispersed Au_1 catalyst is synthesized and applied in electrochemical synthesis of ammonia under ambient conditions. A high NH+4 Faradaic efficiency of 11.1 % achieved by our Au_1 catalyst surpasses most of reported catalysts under comparable conditions. Benefiting from efficient atom utilization, an NH+4 yield rate of 1,305 μg h-1 mg-1Au has been reached, which is roughly 22.5 times as high as that by sup- ported Au nanoparticles. We also demonstrate that by employing our Au_1 catalyst, NH+4 can be electro- chemically produced directly from N_2 and H_2 with an energy utilization rate of 4.02 mmol kJ-1. Our study provides a possibility of replacing the Haber-Bosch process with environmentally benign and energy-efficient electrochemical strategies.展开更多
The ability to controlled introduction of defects, particularly twin defects in Pt-based nanocrystals (NCs) provides a possibility to regulate the performance of Pt-based nanocatalyst. However, because of the high i...The ability to controlled introduction of defects, particularly twin defects in Pt-based nanocrystals (NCs) provides a possibility to regulate the performance of Pt-based nanocatalyst. However, because of the high internal strain energy existed in twinned structures, the fabrication of defects in Pt-based NCs is sufficiently challenging. Here we demonstrate a "low-temperature interface-induced assembly" approach that provides precise control over Pt-Cu nanoparticles assembled at the hexadecylamine/water interface, yielding onion-like Pt-Cu NCs exposed a high density of twin defects. Moreover, a bending mechanism is proposed to elucidate the appearance of twin defects and lattice expanding (contraction) based on aberration corrected scanning transmission electron microscopy analysis. This work opens new routes to engineer defects in metal- based alloy NCs, enabling more opportunities in catalysis.展开更多
We have exploited a new and distinctive combination method that "disperses" elemental Pd into CuS nanoplates. Pd was successfully dispersed by means of the concomitant transformation of CuS into an amorphous sulfide...We have exploited a new and distinctive combination method that "disperses" elemental Pd into CuS nanoplates. Pd was successfully dispersed by means of the concomitant transformation of CuS into an amorphous sulfide, which formed an intimate metal-sulfide contact via cation exchange and underwent a subsequent reduction. A series of such Pd-dispersed CuS hetero-nanoplates were synthesized with tailored proportions and compositions. By efficient utilization of noble metal atoms and stable anchored active sites, the optimal catalytic performance for the semihydrogenation of phenylacetylene, a probe reaction, was achieved with high selectivity, activity, and stability. We believe that the synthetic strategy described in our study is a feasible means of developing effective metal-sulfide catalysts for organic reactions.展开更多
Two-dimensional nanomaterials (2DNMs) have attracted increasing attention due to their unique properties and promising applications. Unlike 2DNMs with lamellar structures, metal ultrathin 2DNMs are difficult to synt...Two-dimensional nanomaterials (2DNMs) have attracted increasing attention due to their unique properties and promising applications. Unlike 2DNMs with lamellar structures, metal ultrathin 2DNMs are difficult to synthesize and stabilize because they tend to form close-packed crystal structures. Most reported cases consist of monometallic and heterogeneous nanostructures. The synthesis of metal alloy 2DNMs has been rarely reported. Here, we report the synthesis of PdNi alloy wavy nanosheets (WNSs) using an enhanced CO-confinement strategy. This strategy is also suitable to the synthesis of other Pd-based alloy WNSs such as PdCu, PdFe, and even a trimetallic PdFeNi.展开更多
Since 7000 BCE,humans have fermented sugars into ethanol,and since work by Louis Pasteur in the 1850s,we have known that microorganisms are responsible for this miraculous feat of chemical synthesis[1].Since then,the ...Since 7000 BCE,humans have fermented sugars into ethanol,and since work by Louis Pasteur in the 1850s,we have known that microorganisms are responsible for this miraculous feat of chemical synthesis[1].Since then,the ability of biological organisms to cheaply and selectively transform chemicals into useful products has been exploited on a global scale from agriculture to biotechnological synthesis of pharmaceutical compounds.Recently,pho-展开更多
Electrocatalyst that converts carbon dioxide to useful fuels,using electricity generated from renewable sources,is generally regarded as a potentially'clean'strategy of turning trash into treasure under mild c...Electrocatalyst that converts carbon dioxide to useful fuels,using electricity generated from renewable sources,is generally regarded as a potentially'clean'strategy of turning trash into treasure under mild conditions[1,2].Lots of studies have demonstrated that electroreduction of CO2contains several elementary steps of adsorption,activation,dissociation and desorption,among which the most展开更多
Molybdenum disulfide (MoS2), a promising non-precious electrocatalyst for the hydrogen evolution reaction with two-dimensional layered structure, has received increasing attention in recent years. Its electrocatalyt...Molybdenum disulfide (MoS2), a promising non-precious electrocatalyst for the hydrogen evolution reaction with two-dimensional layered structure, has received increasing attention in recent years. Its electrocatalytic performance has been limited by the low active site content and poor conductivity. Herein, we report a facile and general ultrafast laser ablation method to synthesize MoS2 quantum dots (MS-QDs) for electrocatalytic HER with fully exposed active sites and highly enhanced conductivity. The MS-QDs were prepared by ultrafast laser ablation of the corresponding bulk material in aqueous solution, during which they were partially oxidized and formed defective structures. The as-prepared MS-QDs demonstrated high activity and stability in the electrocatalytic HER, owing to their very large surface area, defective structure, abundance of active sites, and high conductivity. The present MS-QDs can also find application in optics, sensing, energy storage, and conversion technologies.展开更多
Lower olefins refer to ethylene,propylene and butylene,which are vital building block in the chemical industry.They are fundamental chemicals of the greatest consumption among the organic chemicals all over the world....Lower olefins refer to ethylene,propylene and butylene,which are vital building block in the chemical industry.They are fundamental chemicals of the greatest consumption among the organic chemicals all over the world.Large amount of chemical products,such as packing materials,cosmetics,synthetic rubber,coatings are the derivatives of lower olefins.In traditional petrochemical industry,lower olefins are mainly derived from oil-based feedstocks.展开更多
Over the past decade, extensive collaborative experimental and theoretical researches have systematically elucidated the structures and chemical bonding of boron clusters as a function of size and have revealed an int...Over the past decade, extensive collaborative experimental and theoretical researches have systematically elucidated the structures and chemical bonding of boron clusters as a function of size and have revealed an intriguing set of structures, ranging from planar hydrocarbon-analogs to nanotubular and fullerenelike structures (borospherenes) [1-7]. Small boron clusters have the propensity for planarity with delocalized σ and π electrons over the whole molecular plane, giving rise to the concept of multiple aromatidty.展开更多
基金supported by the National Natural Science Foundation of China (21573119,21221062,21131004,21390393 and U1463202)the Postdoctoral Science Foundation of China (2014M550710)
文摘In this work, ultra-large sheet NiAl-layered double hydroxide(LDH)/reduced graphene oxide(RGO) nanocomposites were facilely synthesized via in situ growth of NiAl-LDH on a graphene surface without any surfactant or template. It was found that with a microwave-assisted method, NiAl-LDH nanosheets grew evenly on the surface of graphene. With this method, the formation of NiAl-LDH and reduction of graphene oxide were achieved in one step. The unique structure endows the electrode materials with a higher specific surface area, which is favorable for enhancing the capacity performance. The morphology and microstructure of the as-prepared composites were characterized by X-ray diffraction, Brunauer-EmmettTeller surface area measurement, and transmission electron microscopy. The specific surface area and pore volume of the RGO/LDH composite are 108.3 m^2 g^(-1) and 0.74 cm^3 g^(-1), respectively, which are much larger than those of pure LDHs(19.8 m^2 g^(-1) and 0.065 cm^3 g(-1), respectively). The capacitive properties of the synthesized electrodes were studied using cyclic voltammetry and electrochemical impedance spectroscopy in a three-electrode experimental setup. The specific capacitance of RGO/LDHs was calculated to be 1055 F g^(-1) at 1 Ag^(-1). It could be anticipated that the synthesized electrodes will find promising applications as novel electrode materials in supercapacitors and other devices because of their outstanding characteristics of controllable capacitance and facile synthesis.
基金supported by the Fundamental Research Funds for the Central Universities(WK2060190043 and WK2060190053)the National Natural Science Foundation of China(21521091,21131004,21390393,U1463202 and 21522107)
文摘This review covers the major reactions involved in the solution synthesis of nanomaterials.It was designed to classify the traditional strategies such as precipitation,reduction,seed growth,etching,and so on into two basic processes which are termed as bottom-up and top-down routines.The discussion is focused on the basic mechanism and principles during the nudeation and growth of nanocrystals,especially in the solution system.This review also presents a prediction for how to utilize these intrinsic processes to artificially construct the desired specific and functional nanostructures.We try to describe the most directive and effective way to control the structures of nanocrystals for researchers who can master the major reaction mechanism and grasp the basic technologies in synthetic nanoscience.
基金supported by the State Key Project of Fundamental Research for Nanoscience and Nanotechnology (2012CB224802)the National Natural Science Foundation of China (21573119,21221062,21131004,21390393,U1463202 and 21325101)Beijing Municipal Commission of Science and Technology (Z141100003814017)
文摘A novel one-pot approach to synthesize the tiara-like Pd(II) thiolate complex compound, [Pd(SCH_3)_2]_6, was developed. In this strategy, dimethyl sulfoxide(DMSO) was used as a thiolate source instead of methyl mercaptan(CH_3SH). DMSO was first decomposed into CH_3SH and formaldehyde(HCHO); then, the in situ as-formed CH_3SH molecules reacted with palladium acetate, and formed [Pd(SCH_3)_2]_6. By tuning the reaction condition, the morphology of the [Pd(SCH_3)_2]_6 assemblies can change from microprism to nanosphere. The characterization of the pyrolysis product demonstrated that these two kinds of [Pd(SCH_3)_2]_6 assemblies with different shapes could further decompose into palladium or palladium sulfides through different pyrolysis conditions.
基金supported by the National Key R&D Program of China (2017YFA0208300)the National Natural Science Foundation of China (21522107, 21671180, 21521091, 21390393, U1463202, and 21522305)
文摘Tremendous efforts have been devoted to explore energy-efficient strategies of ammonia synthesis to replace Haber-Bosch process which accounts for 1.4% of the annual energy consumption. In this study, atomically dispersed Au_1 catalyst is synthesized and applied in electrochemical synthesis of ammonia under ambient conditions. A high NH+4 Faradaic efficiency of 11.1 % achieved by our Au_1 catalyst surpasses most of reported catalysts under comparable conditions. Benefiting from efficient atom utilization, an NH+4 yield rate of 1,305 μg h-1 mg-1Au has been reached, which is roughly 22.5 times as high as that by sup- ported Au nanoparticles. We also demonstrate that by employing our Au_1 catalyst, NH+4 can be electro- chemically produced directly from N_2 and H_2 with an energy utilization rate of 4.02 mmol kJ-1. Our study provides a possibility of replacing the Haber-Bosch process with environmentally benign and energy-efficient electrochemical strategies.
基金The authors wish to thank Mr. Chao Yang for valuable advices. This work was supported by the Foundation for the Author of National Excellent Doctoral Dissertation of P. R. China (No. 201321), the Specialized Research Fund for the Doctoral Program of Higher Education (No. 20130002120013), and the National Natural Science Foundation of China (Nos. 21521091, 21131004, 21390393, 21322107, 21325101, 21471089, and U1463202).
文摘The ability to controlled introduction of defects, particularly twin defects in Pt-based nanocrystals (NCs) provides a possibility to regulate the performance of Pt-based nanocatalyst. However, because of the high internal strain energy existed in twinned structures, the fabrication of defects in Pt-based NCs is sufficiently challenging. Here we demonstrate a "low-temperature interface-induced assembly" approach that provides precise control over Pt-Cu nanoparticles assembled at the hexadecylamine/water interface, yielding onion-like Pt-Cu NCs exposed a high density of twin defects. Moreover, a bending mechanism is proposed to elucidate the appearance of twin defects and lattice expanding (contraction) based on aberration corrected scanning transmission electron microscopy analysis. This work opens new routes to engineer defects in metal- based alloy NCs, enabling more opportunities in catalysis.
基金The presented research was financially supported by the National Natural Science Foundation of China (Nos. 21325101, 21231005, and 21171105).
文摘We have exploited a new and distinctive combination method that "disperses" elemental Pd into CuS nanoplates. Pd was successfully dispersed by means of the concomitant transformation of CuS into an amorphous sulfide, which formed an intimate metal-sulfide contact via cation exchange and underwent a subsequent reduction. A series of such Pd-dispersed CuS hetero-nanoplates were synthesized with tailored proportions and compositions. By efficient utilization of noble metal atoms and stable anchored active sites, the optimal catalytic performance for the semihydrogenation of phenylacetylene, a probe reaction, was achieved with high selectivity, activity, and stability. We believe that the synthetic strategy described in our study is a feasible means of developing effective metal-sulfide catalysts for organic reactions.
基金This work was supported by the National Natural Science Foundation of China (Nos. 21573119, 21590792, 21521091, 21131004, 21390393, and U1463202).
文摘Two-dimensional nanomaterials (2DNMs) have attracted increasing attention due to their unique properties and promising applications. Unlike 2DNMs with lamellar structures, metal ultrathin 2DNMs are difficult to synthesize and stabilize because they tend to form close-packed crystal structures. Most reported cases consist of monometallic and heterogeneous nanostructures. The synthesis of metal alloy 2DNMs has been rarely reported. Here, we report the synthesis of PdNi alloy wavy nanosheets (WNSs) using an enhanced CO-confinement strategy. This strategy is also suitable to the synthesis of other Pd-based alloy WNSs such as PdCu, PdFe, and even a trimetallic PdFeNi.
文摘Since 7000 BCE,humans have fermented sugars into ethanol,and since work by Louis Pasteur in the 1850s,we have known that microorganisms are responsible for this miraculous feat of chemical synthesis[1].Since then,the ability of biological organisms to cheaply and selectively transform chemicals into useful products has been exploited on a global scale from agriculture to biotechnological synthesis of pharmaceutical compounds.Recently,pho-
基金We thank the financial supports by the National Natural Science Foundation of China (Nos.21221062 and 21521091) and the National Basic Research Program of China (973 program,No.2013CB932800).
文摘Electrocatalyst that converts carbon dioxide to useful fuels,using electricity generated from renewable sources,is generally regarded as a potentially'clean'strategy of turning trash into treasure under mild conditions[1,2].Lots of studies have demonstrated that electroreduction of CO2contains several elementary steps of adsorption,activation,dissociation and desorption,among which the most
文摘Molybdenum disulfide (MoS2), a promising non-precious electrocatalyst for the hydrogen evolution reaction with two-dimensional layered structure, has received increasing attention in recent years. Its electrocatalytic performance has been limited by the low active site content and poor conductivity. Herein, we report a facile and general ultrafast laser ablation method to synthesize MoS2 quantum dots (MS-QDs) for electrocatalytic HER with fully exposed active sites and highly enhanced conductivity. The MS-QDs were prepared by ultrafast laser ablation of the corresponding bulk material in aqueous solution, during which they were partially oxidized and formed defective structures. The as-prepared MS-QDs demonstrated high activity and stability in the electrocatalytic HER, owing to their very large surface area, defective structure, abundance of active sites, and high conductivity. The present MS-QDs can also find application in optics, sensing, energy storage, and conversion technologies.
文摘Lower olefins refer to ethylene,propylene and butylene,which are vital building block in the chemical industry.They are fundamental chemicals of the greatest consumption among the organic chemicals all over the world.Large amount of chemical products,such as packing materials,cosmetics,synthetic rubber,coatings are the derivatives of lower olefins.In traditional petrochemical industry,lower olefins are mainly derived from oil-based feedstocks.
文摘Over the past decade, extensive collaborative experimental and theoretical researches have systematically elucidated the structures and chemical bonding of boron clusters as a function of size and have revealed an intriguing set of structures, ranging from planar hydrocarbon-analogs to nanotubular and fullerenelike structures (borospherenes) [1-7]. Small boron clusters have the propensity for planarity with delocalized σ and π electrons over the whole molecular plane, giving rise to the concept of multiple aromatidty.