Synchrotron radiation based combined technique can provide multiple structural information simultaneously,which is an important development direction of structural detection.In this study,a novel small-angle X-ray sca...Synchrotron radiation based combined technique can provide multiple structural information simultaneously,which is an important development direction of structural detection.In this study,a novel small-angle X-ray scattering/X-ray diffraction/X-ray absorption fine structure(SAXS/XRD/XAFS)combined setup was constructed,where an area detector,a curved detector,and a point detector are,respectively,used for the measurements of SAXS,XRD,and XAFS signals.A detailed description about the combined setup was given.A minitype diamond detector coupled to a SAXS beamstop was used to record the transmitted X-ray intensity,making the scattering(SAXS and XRD)signal measurement compatible with the absorption(XAFS)signal measurement,avoiding mechanical switching.The two-way sampling strategy was used to acquire XAFS signals,shortening the non-counting time.The two-way and one-way sampling strategies were discussed.High-frequency sampling scheme was used to collect experimental signals,improving the measurement efficiency and signal-to-noise ratio.A detailed description and discussion about the high-frequency scheme were also given in this paper.Except the rotation of monochromator,there is no mechanical movement in measurements,time resolution may reach the level of seconds.Using this SAXS/XRD/XAFS combined setup,SAXS,XRD,and XAFS signals can be acquired simultaneously.With some in-situ sample environment system,the newlydeveloped combined technique can be used to track the structure evolution in complex fluids.During the formation processes of(BiO)2CO3 and ZnAPO-34 particles,the changes of in-situ experimental data with reaction time demonstrate that SAXS/XRD/XAFS combined technique is feasible to track the dynamic process.展开更多
To develop high-performance metal-organic frameworks(MOFs)for catalysis is of great importance.Here,we synthesized the mesoporous Cu_(3−x)Zn_(x)(BTC)_(2)(BTC=benzene-1,3,5-tricarboxylate)nanocubes in a deep eutectic s...To develop high-performance metal-organic frameworks(MOFs)for catalysis is of great importance.Here,we synthesized the mesoporous Cu_(3−x)Zn_(x)(BTC)_(2)(BTC=benzene-1,3,5-tricarboxylate)nanocubes in a deep eutectic solvent of ZnCl_(2)/ethylene glycol solution.The route can proceed at room temperature and the reaction time needed is shortened to be 30 min,which is superior to the conventional solvothermal route that usually needs high temperature and long reaction time.The formation mechanism of the mesoporous Cu_(3−x)Zn_(x)(BTC)_(2)nanocubes in deep eutectic solvent(DES)was investigated by in situ synchrotron X-ray diffraction/small angle X-ray scattering/X-ray absorption fine structure conjunction technique.The mesoporous Cu_(3−x)Zn_(x)(BTC)_(2)nanocubes exhibit high catalytic activity and reusability for cyanosilylation reaction of benzaldehyde and aerobic oxidation reaction of benzylic alcohol.展开更多
Introduction Nanofiber orientation in suspensions determines the performance of nanoparticle suspensions which have potential applications in intelligent control.Material and method Na2Ti3O7 nanofibers were prepared w...Introduction Nanofiber orientation in suspensions determines the performance of nanoparticle suspensions which have potential applications in intelligent control.Material and method Na2Ti3O7 nanofibers were prepared with a hydrothermal method.The orientation degree of Na2Ti3O7 nanofibers in silicone oil has been studied by in situ small-angle X-ray scattering technique.Thünemann–Ruland method was used to extract the distribution widths of Na2Ti3O7 nanofibers in the suspensions.Conclution An empirical formula has been proposed to describe the dependence of nanofiber orientation degree on the external electric-field strength(E)and the nanofiber concentration(C).The results demonstrate that the response of nanofiber orientation to the electric field can be divided into exponential and linear stages before and after the inflection point of electric-field strength(Ec0.09 kV/mm).Low concentration of suspension is more sensitive to the external electric field.The increase in nanofiber concentration will decrease the response sensitivity of nanofiber orientation degree to the change of E.The critical concentration of Na2Ti3O7 nanofibers in the suspension is about 5 wt%.This study is expected to give new clue for the structurally responsive mechanism of anisotropic nanoparticles in suspensions to electric-field strength and particle concentration.展开更多
基金This work was supported by the National Key Research and Development Program of China(Nos.2017YFA0403000 and 2017YFA0403100).
文摘Synchrotron radiation based combined technique can provide multiple structural information simultaneously,which is an important development direction of structural detection.In this study,a novel small-angle X-ray scattering/X-ray diffraction/X-ray absorption fine structure(SAXS/XRD/XAFS)combined setup was constructed,where an area detector,a curved detector,and a point detector are,respectively,used for the measurements of SAXS,XRD,and XAFS signals.A detailed description about the combined setup was given.A minitype diamond detector coupled to a SAXS beamstop was used to record the transmitted X-ray intensity,making the scattering(SAXS and XRD)signal measurement compatible with the absorption(XAFS)signal measurement,avoiding mechanical switching.The two-way sampling strategy was used to acquire XAFS signals,shortening the non-counting time.The two-way and one-way sampling strategies were discussed.High-frequency sampling scheme was used to collect experimental signals,improving the measurement efficiency and signal-to-noise ratio.A detailed description and discussion about the high-frequency scheme were also given in this paper.Except the rotation of monochromator,there is no mechanical movement in measurements,time resolution may reach the level of seconds.Using this SAXS/XRD/XAFS combined setup,SAXS,XRD,and XAFS signals can be acquired simultaneously.With some in-situ sample environment system,the newlydeveloped combined technique can be used to track the structure evolution in complex fluids.During the formation processes of(BiO)2CO3 and ZnAPO-34 particles,the changes of in-situ experimental data with reaction time demonstrate that SAXS/XRD/XAFS combined technique is feasible to track the dynamic process.
基金support by Ministry of Science and Technology of China(No.2017YFA0403003)the National Natural Science Foundation of China(Nos.22033009 and 22121002).
文摘To develop high-performance metal-organic frameworks(MOFs)for catalysis is of great importance.Here,we synthesized the mesoporous Cu_(3−x)Zn_(x)(BTC)_(2)(BTC=benzene-1,3,5-tricarboxylate)nanocubes in a deep eutectic solvent of ZnCl_(2)/ethylene glycol solution.The route can proceed at room temperature and the reaction time needed is shortened to be 30 min,which is superior to the conventional solvothermal route that usually needs high temperature and long reaction time.The formation mechanism of the mesoporous Cu_(3−x)Zn_(x)(BTC)_(2)nanocubes in deep eutectic solvent(DES)was investigated by in situ synchrotron X-ray diffraction/small angle X-ray scattering/X-ray absorption fine structure conjunction technique.The mesoporous Cu_(3−x)Zn_(x)(BTC)_(2)nanocubes exhibit high catalytic activity and reusability for cyanosilylation reaction of benzaldehyde and aerobic oxidation reaction of benzylic alcohol.
基金the Ministry of Science and Technology of China(Grant No.2017YFA0403000)the National Natural Science Foundation of China(Grant No.11405199).
文摘Introduction Nanofiber orientation in suspensions determines the performance of nanoparticle suspensions which have potential applications in intelligent control.Material and method Na2Ti3O7 nanofibers were prepared with a hydrothermal method.The orientation degree of Na2Ti3O7 nanofibers in silicone oil has been studied by in situ small-angle X-ray scattering technique.Thünemann–Ruland method was used to extract the distribution widths of Na2Ti3O7 nanofibers in the suspensions.Conclution An empirical formula has been proposed to describe the dependence of nanofiber orientation degree on the external electric-field strength(E)and the nanofiber concentration(C).The results demonstrate that the response of nanofiber orientation to the electric field can be divided into exponential and linear stages before and after the inflection point of electric-field strength(Ec0.09 kV/mm).Low concentration of suspension is more sensitive to the external electric field.The increase in nanofiber concentration will decrease the response sensitivity of nanofiber orientation degree to the change of E.The critical concentration of Na2Ti3O7 nanofibers in the suspension is about 5 wt%.This study is expected to give new clue for the structurally responsive mechanism of anisotropic nanoparticles in suspensions to electric-field strength and particle concentration.
