Bi（0.76）Sb（1.24）S3 nanocrystals were synthesized by a rapid microwave-assisted hydrothermal method using bismuth nitrate, antimony pentoxide and thioacetamide as starting materials and characterized by X-ray diffr...Bi（0.76）Sb（1.24）S3 nanocrystals were synthesized by a rapid microwave-assisted hydrothermal method using bismuth nitrate, antimony pentoxide and thioacetamide as starting materials and characterized by X-ray diffraction（XRD）, scanning electron microscopy（SEM） and UV-vis diffuse reflectance spectroscopy（DRS）. The effects of the synthetic condition on the product composition were investigated. The photocatalytic activities of Bi（0.76）Sb（1.24）S3 nanocrystals for the degradation of methyl orange and p-hydroxyazobenzene under visible light irradiation were evaluated. Bi（0.76）Sb（1.24）S3 exhibited good and stable visible light photocatalytic activity.展开更多
Al-doped ZnO (ZAO) films were successfully deposited on the surface of common glasses by using low-temperature hydrothermal approach. In the reaction solution, the molar ratio of Al3+ to Zn2+ was 1∶100, the annealing...Al-doped ZnO (ZAO) films were successfully deposited on the surface of common glasses by using low-temperature hydrothermal approach. In the reaction solution, the molar ratio of Al3+ to Zn2+ was 1∶100, the annealing temperature and time were 200 ℃ and 2-6 h, respectively. The structure of the thin films was identified by X-ray diffraction (XRD), the surface morphology and thickness of the thin films were observed by scanning electron microscopy (SEM), and the electrical performance of the thin films was measured by four-point probes. It was shown that the films with an average particle size of 27.53 nm had a preferential orientation along (002), Al3+ had replaced the position of Zn2+ in the lattice without forming the Al2O3 phase and its thickness was 20-25 μm. With the increased annealing time, the intensity of diffraction peaks was decreased, the film exhibited irregular surface morphology gradually, and the resistivity of ZAO films was increased. The lowest resistivity obtained in this study was 3.45×10-5Ω·cm.展开更多
Economical water electrolysis requires highly active non-noble electrocatalysts to overcome the sluggish kinetics of the two half-cell reactions,oxygen evolution reaction,and hydrogen evolution reaction.Although inten...Economical water electrolysis requires highly active non-noble electrocatalysts to overcome the sluggish kinetics of the two half-cell reactions,oxygen evolution reaction,and hydrogen evolution reaction.Although intensive efforts have been committed to achieve a hydrogen economy,the expensive noble metal-based catalysts remain under consideration.Therefore,the engineering of self-supported electrocatalysts prepared using a direct growth strategy on three-dimensional(3D)nickel foam(NF)as a conductive substrate has garnered significant interest.This is due to the large active surface area and 3D porous network offered by these electrocatalysts,which can enhance the synergistic eff ect between the catalyst and the substrate,as well as improve electrocatalytic performance.Hydrothermal-assisted growth,microwave heating,electrodeposition,and other physical methods(i.e.,chemical vapor deposition and plasma treatment)have been applied to NF to fabricate competitive electrocatalysts with low overpotential and high stability.In this review,recent advancements in the development of self-supported electrocatalysts on 3D NF are described.Finally,we provide future perspectives of self-supported electrode platforms in electrochemical water splitting.展开更多
Hydrothermal methods are widely used in chemical synthesis of target products with specific morphology and nanostructure.Those methods are very efficient for the preparation of well-controlled structures but the react...Hydrothermal methods are widely used in chemical synthesis of target products with specific morphology and nanostructure.Those methods are very efficient for the preparation of well-controlled structures but the reaction time is usually long.The assistance of microwave makes the reaction system heat up faster,more uniformly and reactions are accelerated,it also can be utilized to change the morphology or structure of materials,which improves the physic-chemical properties of synthesized products and influences its gas-sensing performance.Copper oxide(CuO)is widely applied in semiconductor gas sensors because of its good reactivity and stability.This review article briefly introduces the principle,mechanism and recent development of CuO nanostructures obtained by microwave-as sis ted hydrothermal synthesis(MWHS)process.It also discussed the relation between endopathic factors of material and its gas-sensitive performance.The technical challenges and prospective solutions for highperformance CuO-based gas-sensitive materials with unique nanostructure are proposed.It is pointed out that the hierarchical CuO-based nanostructures and their composite materials prepared by MWHS process are efficacious methods to improve the gas-sensitive performance of the materials.On the basis of the morphology,the materials are divided into nanorods,nanoflowers,nanosheets,nanospheres and other nanostructures.The influence of microwave parameters on the properties of synthetic products is analyzed.The influence followed by metal element loading on the structure and properties of CuO-based materials by MWHS process is further discussed.Then this review summarizes the research progress of graphene-CuO and metal oxide-CuO composites prepared by MWHS process in recent years.展开更多
Precursors for nanostructured SnO2 were synthesized via a microwave-assisted hydrothermal method under different conditions, using SnCI2.2H2 O, urea and citric acid as reactants. After calcination of the pre-cursors a...Precursors for nanostructured SnO2 were synthesized via a microwave-assisted hydrothermal method under different conditions, using SnCI2.2H2 O, urea and citric acid as reactants. After calcination of the pre-cursors at 700 ℃ for 2 h, nanostructured SnO2 with different morphologies were obtained, and were then characterized using X-ray powder diffraction （XRD）, and field-emission scanning electron microscopy （FESEM）. The results show that synthesis temperature and time play an important role in the formation of the 3D hierarchical morphology of the nanostructured SnO2. Gas sensing experiments demonstrate that the synthesized SnO2 materials, especially those with a 3D network structure, exhibit superb sensitivity to alcohol vaoors at 240 ℃.展开更多
SrWO4：Eu^3＋ nanowires were synthesized at 160 ℃ within 10 min via a microwave-assisted hydrothermal method. In examining the influences of synthesis temperature and reaction time on the morphology of nanowires, it ...SrWO4：Eu^3＋ nanowires were synthesized at 160 ℃ within 10 min via a microwave-assisted hydrothermal method. In examining the influences of synthesis temperature and reaction time on the morphology of nanowires, it was found that any temperatures and reaction time except 160 ℃ and 10 min gave rise to poorer morphologies under otherwise equal conditions. The synthesized nanowires were characterized by means of X-ray diffraction（XRD）, scanning electron microscopy（SEM）, transmission electron microscopy（TEM）, high-resolution transmission electron microscopy（HRTEM）, energy dispersive X-ray（EDX） and Raman spectrometry, respectively. The results suggest that the samples are homogenous and dispersive single phase nanowires. The photoluminescence properties of the nanowires were determined with a spectrofluorometer. Two obviously sharp peaks at 395 and 464 nm and a broad peak centered at 290 nm were found in their excitation spectrum. Under excitation at 395 and 464 nm, the ^5D0→^7F2 transition is the dominant process which means Eu^3＋ ion is located at a low symmetry site, while the ^5D0→^7F2 transition dominates under the excitation at 290 nm, showing a highly symmetric field around the Eu^3＋ ion, which indicates the presence of the two local Eu^3＋ environments.展开更多
Hierarchical microspheres of a graphene oxide（GO） coupled to N‐doped（BiO）2CO3 composite（N‐BOC‐GO） was synthesized by a simple hydrothermal approach. The N‐BOC‐GO composite gave enhancement in photocatalytic...Hierarchical microspheres of a graphene oxide（GO） coupled to N‐doped（BiO）2CO3 composite（N‐BOC‐GO） was synthesized by a simple hydrothermal approach. The N‐BOC‐GO composite gave enhancement in photocatalytic activity compared to the pure BOC and N‐BOC samples. With 1.0wt% GO, 62% NO removal was obtained with N‐BOC‐GO. The factors enhancing the photocatalytic performance were the high electron‐withdrawing ability and high conductivity of GO and improved visible light‐harvesting ability of N‐BOC‐GO with a 3D hierarchical architecture due to the surface scattering and reflecting（SSR） effect. An effective charge transfer from N‐BOC to GO was demonstrated by the much weakened photoluminescene intensity of the N‐BOC‐GO composite. This work highlights the potential application of GO‐based photocatalysts in air purification.展开更多
基金supported by the National Natural Science Foundation of China(21307012)Educational Commission of Fujian Province(JK2013007,2014J01035,JA15138)
文摘Bi（0.76）Sb（1.24）S3 nanocrystals were synthesized by a rapid microwave-assisted hydrothermal method using bismuth nitrate, antimony pentoxide and thioacetamide as starting materials and characterized by X-ray diffraction（XRD）, scanning electron microscopy（SEM） and UV-vis diffuse reflectance spectroscopy（DRS）. The effects of the synthetic condition on the product composition were investigated. The photocatalytic activities of Bi（0.76）Sb（1.24）S3 nanocrystals for the degradation of methyl orange and p-hydroxyazobenzene under visible light irradiation were evaluated. Bi（0.76）Sb（1.24）S3 exhibited good and stable visible light photocatalytic activity.
文摘Al-doped ZnO (ZAO) films were successfully deposited on the surface of common glasses by using low-temperature hydrothermal approach. In the reaction solution, the molar ratio of Al3+ to Zn2+ was 1∶100, the annealing temperature and time were 200 ℃ and 2-6 h, respectively. The structure of the thin films was identified by X-ray diffraction (XRD), the surface morphology and thickness of the thin films were observed by scanning electron microscopy (SEM), and the electrical performance of the thin films was measured by four-point probes. It was shown that the films with an average particle size of 27.53 nm had a preferential orientation along (002), Al3+ had replaced the position of Zn2+ in the lattice without forming the Al2O3 phase and its thickness was 20-25 μm. With the increased annealing time, the intensity of diffraction peaks was decreased, the film exhibited irregular surface morphology gradually, and the resistivity of ZAO films was increased. The lowest resistivity obtained in this study was 3.45×10-5Ω·cm.
基金supported by The Chinese Academy of Sciences (CAS) President’s International Fellowship Initiative (No. 2023VCB0014)The National Natural Science Foundation of China (No. 52203284)Shenzhen Science and Technology Program (Nos. GJHZ20220913143801003 and RCBS20221008093057026)
文摘Economical water electrolysis requires highly active non-noble electrocatalysts to overcome the sluggish kinetics of the two half-cell reactions,oxygen evolution reaction,and hydrogen evolution reaction.Although intensive efforts have been committed to achieve a hydrogen economy,the expensive noble metal-based catalysts remain under consideration.Therefore,the engineering of self-supported electrocatalysts prepared using a direct growth strategy on three-dimensional(3D)nickel foam(NF)as a conductive substrate has garnered significant interest.This is due to the large active surface area and 3D porous network offered by these electrocatalysts,which can enhance the synergistic eff ect between the catalyst and the substrate,as well as improve electrocatalytic performance.Hydrothermal-assisted growth,microwave heating,electrodeposition,and other physical methods(i.e.,chemical vapor deposition and plasma treatment)have been applied to NF to fabricate competitive electrocatalysts with low overpotential and high stability.In this review,recent advancements in the development of self-supported electrocatalysts on 3D NF are described.Finally,we provide future perspectives of self-supported electrode platforms in electrochemical water splitting.
基金financially supported by the National Key Research and Development Program of China(No.2017YFE0115900)the Natural Science Foundation of China(No.51872254)Yangzhou City-Yangzhou University Cooperation Foundation(No.YZU201801)。
文摘Hydrothermal methods are widely used in chemical synthesis of target products with specific morphology and nanostructure.Those methods are very efficient for the preparation of well-controlled structures but the reaction time is usually long.The assistance of microwave makes the reaction system heat up faster,more uniformly and reactions are accelerated,it also can be utilized to change the morphology or structure of materials,which improves the physic-chemical properties of synthesized products and influences its gas-sensing performance.Copper oxide(CuO)is widely applied in semiconductor gas sensors because of its good reactivity and stability.This review article briefly introduces the principle,mechanism and recent development of CuO nanostructures obtained by microwave-as sis ted hydrothermal synthesis(MWHS)process.It also discussed the relation between endopathic factors of material and its gas-sensitive performance.The technical challenges and prospective solutions for highperformance CuO-based gas-sensitive materials with unique nanostructure are proposed.It is pointed out that the hierarchical CuO-based nanostructures and their composite materials prepared by MWHS process are efficacious methods to improve the gas-sensitive performance of the materials.On the basis of the morphology,the materials are divided into nanorods,nanoflowers,nanosheets,nanospheres and other nanostructures.The influence of microwave parameters on the properties of synthetic products is analyzed.The influence followed by metal element loading on the structure and properties of CuO-based materials by MWHS process is further discussed.Then this review summarizes the research progress of graphene-CuO and metal oxide-CuO composites prepared by MWHS process in recent years.
基金supported by the Foundation for Excellent Middle-aged or Young Scientists from Shandong Province under Grants No.BS2009CL029 and No.BS2010CL007supported by National Natural Science Foundation of China(NSFC,No.60906008)the Scientific Research Foundation for Returned Overseas Chinese Scholars from State Education Ministry(SQT 1102)
文摘Precursors for nanostructured SnO2 were synthesized via a microwave-assisted hydrothermal method under different conditions, using SnCI2.2H2 O, urea and citric acid as reactants. After calcination of the pre-cursors at 700 ℃ for 2 h, nanostructured SnO2 with different morphologies were obtained, and were then characterized using X-ray powder diffraction （XRD）, and field-emission scanning electron microscopy （FESEM）. The results show that synthesis temperature and time play an important role in the formation of the 3D hierarchical morphology of the nanostructured SnO2. Gas sensing experiments demonstrate that the synthesized SnO2 materials, especially those with a 3D network structure, exhibit superb sensitivity to alcohol vaoors at 240 ℃.
基金Supported by the National Natural Science Foundation of China（Nos.21271082, 21371068） and the China Postdoctoral Science Foundation（No. 801141080411）.
文摘SrWO4：Eu^3＋ nanowires were synthesized at 160 ℃ within 10 min via a microwave-assisted hydrothermal method. In examining the influences of synthesis temperature and reaction time on the morphology of nanowires, it was found that any temperatures and reaction time except 160 ℃ and 10 min gave rise to poorer morphologies under otherwise equal conditions. The synthesized nanowires were characterized by means of X-ray diffraction（XRD）, scanning electron microscopy（SEM）, transmission electron microscopy（TEM）, high-resolution transmission electron microscopy（HRTEM）, energy dispersive X-ray（EDX） and Raman spectrometry, respectively. The results suggest that the samples are homogenous and dispersive single phase nanowires. The photoluminescence properties of the nanowires were determined with a spectrofluorometer. Two obviously sharp peaks at 395 and 464 nm and a broad peak centered at 290 nm were found in their excitation spectrum. Under excitation at 395 and 464 nm, the ^5D0→^7F2 transition is the dominant process which means Eu^3＋ ion is located at a low symmetry site, while the ^5D0→^7F2 transition dominates under the excitation at 290 nm, showing a highly symmetric field around the Eu^3＋ ion, which indicates the presence of the two local Eu^3＋ environments.
基金supported by the National Natural Science Foundation of China(21277097)the Key Projects in the National Science&Technology Pillar Program during the 12th Five-Year Plan Period(2012BAJ21B01)~~
文摘Hierarchical microspheres of a graphene oxide（GO） coupled to N‐doped（BiO）2CO3 composite（N‐BOC‐GO） was synthesized by a simple hydrothermal approach. The N‐BOC‐GO composite gave enhancement in photocatalytic activity compared to the pure BOC and N‐BOC samples. With 1.0wt% GO, 62% NO removal was obtained with N‐BOC‐GO. The factors enhancing the photocatalytic performance were the high electron‐withdrawing ability and high conductivity of GO and improved visible light‐harvesting ability of N‐BOC‐GO with a 3D hierarchical architecture due to the surface scattering and reflecting（SSR） effect. An effective charge transfer from N‐BOC to GO was demonstrated by the much weakened photoluminescene intensity of the N‐BOC‐GO composite. This work highlights the potential application of GO‐based photocatalysts in air purification.
