ZnO can be made into many nanostructures that have unique properties for advanced applications, such as piezoelectric and pyroelectric materials. ZnOnanorod is one of the nanostructures that possess advanced propertie...ZnO can be made into many nanostructures that have unique properties for advanced applications, such as piezoelectric and pyroelectric materials. ZnOnanorod is one of the nanostructures that possess advanced properties. This paper reports a gas phase flame process to continuously synthesize aerosols of ZnOnanorods in large quantities. Unlike previous work, our process shows that pure ZnOnanorods can be made in a freestanding form rather than growing on a substrate surface. It was found that the ZnOnanorods preferentially grow in the thermodynamically stable direction [001] in the gas phase with different aspect ratios, depending on flame process conditions. The ZnOnanorod aerosols are highly crystalline and have a hexagonal geometry. Raman and photoluminescence spectroscopic studies showed that there are no structural defects in the nanorods, which have energy band gap of 3.27 eV in the near UV region. It was demonstrated that the gas phase flame reactor can provide a convenient means for continuous production of highly pure aerosols of ZnOnanorods.展开更多
Zirconium metal-organic frameworks（Zr-MOFs） represent the most promising candidates among MOFs for industrial utilizations owing to their high porosity and excellent stability. However, the efficient synthesis of Zr...Zirconium metal-organic frameworks（Zr-MOFs） represent the most promising candidates among MOFs for industrial utilizations owing to their high porosity and excellent stability. However, the efficient synthesis of Zr-MOFs combining with continuous production, high productivity and good product quality still remains a critical issue for practical applications. Herein, we report an efficient method of synthesizing a series of Zr-MOFs through a microdroplet flow reaction, which is more accommodate the requirements of industrial production. Four types of Zr-based MOFs with different ligands and topologies（MOF-801, MOF-804, DUT-67 and MOF-808） were produced as a pure phase of high quality crystalline with uniform morphologies. Furthermore, this series of Zr-MOFs were obtained in a continuous way and at a space-time yield（STY） highly up to 367.2 kg m-3 d-1. These MOFs exhibit the similar pore structure and thermal stability with that prepared from conventional solvothermal synthesis. CO2 sorption studies on these MOFs demonstrate that the hydroxyl groups on ligand can render MOFs with high CO2/N2 selectivity.展开更多
Over the past decades,there have been many synthesis methods on producing well-defined crystals,due to their enormous application potentials in industrial field.Among them,high temperature gas-phase reactions(HTGR)app...Over the past decades,there have been many synthesis methods on producing well-defined crystals,due to their enormous application potentials in industrial field.Among them,high temperature gas-phase reactions(HTGR)approach may be one of the most promising processes for fabrication of well-defined crystals with controllable structure,size,shape,and composition.This review is focused on the recent progresses in synthesizing well-defined crystalline TiO2dominated with,respectively,{001}facets and{105}facets,one-dimensional ZnO and SnO2nanorods/nanowires,MoS2nanosheets as well as GaP,InP,and GaAs nanowires via HTGR approach.Although these research works were currently carried out on experimental scale,it is worth to note that the industrial importance of this HTGR approach for design and fabrication of well-defined crystals in the future owing to its advantages of continuous and scalable production with controlled dimensions and low cost.展开更多
Carbonated hydroxyapatites(CHA) were rapidly and continuously synthesized in supercritical water by using a tubular reactor. The effects of reaction time and the ratio of PO43-/CO32-on the apatite structure were inves...Carbonated hydroxyapatites(CHA) were rapidly and continuously synthesized in supercritical water by using a tubular reactor. The effects of reaction time and the ratio of PO43-/CO32-on the apatite structure were investigated by using XRD, FTIR and TEM. Results showed that 30 seconds were enough to produce fully crystalline CHA nano-rods, ca. 20×70 nm in size, at 380 ℃ and 24 MPa. When the ratio of PO43-/CO32-was not less than 1, the CO32-ions mainly substituted for PO43-in apatite structure; but CO32-ions could react with Ca2+ to form CaCO3 phase when the ratio of PO43-/CO32-was less than 1.展开更多
文摘ZnO can be made into many nanostructures that have unique properties for advanced applications, such as piezoelectric and pyroelectric materials. ZnOnanorod is one of the nanostructures that possess advanced properties. This paper reports a gas phase flame process to continuously synthesize aerosols of ZnOnanorods in large quantities. Unlike previous work, our process shows that pure ZnOnanorods can be made in a freestanding form rather than growing on a substrate surface. It was found that the ZnOnanorods preferentially grow in the thermodynamically stable direction [001] in the gas phase with different aspect ratios, depending on flame process conditions. The ZnOnanorod aerosols are highly crystalline and have a hexagonal geometry. Raman and photoluminescence spectroscopic studies showed that there are no structural defects in the nanorods, which have energy band gap of 3.27 eV in the near UV region. It was demonstrated that the gas phase flame reactor can provide a convenient means for continuous production of highly pure aerosols of ZnOnanorods.
基金supported by grants from the National Natural Science Foundation of China (Nos. 21401215, 21473254)the Special Project Fund of "Taishan Scholars" of Shandong Province (No. ts201511017)
文摘Zirconium metal-organic frameworks（Zr-MOFs） represent the most promising candidates among MOFs for industrial utilizations owing to their high porosity and excellent stability. However, the efficient synthesis of Zr-MOFs combining with continuous production, high productivity and good product quality still remains a critical issue for practical applications. Herein, we report an efficient method of synthesizing a series of Zr-MOFs through a microdroplet flow reaction, which is more accommodate the requirements of industrial production. Four types of Zr-based MOFs with different ligands and topologies（MOF-801, MOF-804, DUT-67 and MOF-808） were produced as a pure phase of high quality crystalline with uniform morphologies. Furthermore, this series of Zr-MOFs were obtained in a continuous way and at a space-time yield（STY） highly up to 367.2 kg m-3 d-1. These MOFs exhibit the similar pore structure and thermal stability with that prepared from conventional solvothermal synthesis. CO2 sorption studies on these MOFs demonstrate that the hydroxyl groups on ligand can render MOFs with high CO2/N2 selectivity.
基金supported by the National Natural Science Foundation of China (91022023,21076076)the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry (SRF for ROCS,SEM)+2 种基金Programme for Professor of Special Appointment (Eastern Scholar) at Shanghai Institutions of Higher LearningMajor Basic Research Programme of Science and Technology Commission of Shanghai Municipality (10JC1403200)Shanghai Municipal Natural Science Foundation (12ZR1407500)
文摘Over the past decades,there have been many synthesis methods on producing well-defined crystals,due to their enormous application potentials in industrial field.Among them,high temperature gas-phase reactions(HTGR)approach may be one of the most promising processes for fabrication of well-defined crystals with controllable structure,size,shape,and composition.This review is focused on the recent progresses in synthesizing well-defined crystalline TiO2dominated with,respectively,{001}facets and{105}facets,one-dimensional ZnO and SnO2nanorods/nanowires,MoS2nanosheets as well as GaP,InP,and GaAs nanowires via HTGR approach.Although these research works were currently carried out on experimental scale,it is worth to note that the industrial importance of this HTGR approach for design and fabrication of well-defined crystals in the future owing to its advantages of continuous and scalable production with controlled dimensions and low cost.
文摘Carbonated hydroxyapatites(CHA) were rapidly and continuously synthesized in supercritical water by using a tubular reactor. The effects of reaction time and the ratio of PO43-/CO32-on the apatite structure were investigated by using XRD, FTIR and TEM. Results showed that 30 seconds were enough to produce fully crystalline CHA nano-rods, ca. 20×70 nm in size, at 380 ℃ and 24 MPa. When the ratio of PO43-/CO32-was not less than 1, the CO32-ions mainly substituted for PO43-in apatite structure; but CO32-ions could react with Ca2+ to form CaCO3 phase when the ratio of PO43-/CO32-was less than 1.
