The photocatalytic performances of water oxidation were usually carried out in two different systems,photosensitizer and non-photosensitizer systems.There is few report about the same catalyst used in two systems and ...The photocatalytic performances of water oxidation were usually carried out in two different systems,photosensitizer and non-photosensitizer systems.There is few report about the same catalyst used in two systems and therefore it is of great significant to compare its role of the same catalyst in two systems and explore its different reaction mechanisms.In this work,first 4 kinds of metallic Co microparticles were obtained by different reduction methods through hydrothermal processes,and Co@Co_(3)O_(4) coreshell microparticles(1-4)were obtained from these metallic Co microparticles oxidized in air or in the reacting solution in situ.The core-shell structure of 1 was characterized by a series of analytical techniques.1-4 exhibited excellent activities and stabilities in the[Ru(bpy)3]^(2+)/S_(2) O_(8)^(2-)/light system when they were used as catalysts for the photocata lytic water oxidation.The maximum O2 evolution of 1 after 20 min’s illumination was 98.2 pmol,the O_(2) yield was 65.5%,the initial turnover frequency was 6.6×10^(-3),the initial quantum efficiency(ΦQYinitial)was 15.0%higher than Co(8.3%),CoO(11.7%),Co_(2)O_(3)(1.2%),Co_(3)O_(4)(2.8%)and 5(2.2%).Even after the sixth run,the catalytic activity of recovered 1 still remained 85.1%of initial activity.In addition,the photocatalytic performances of 1 in the[Ru(bpy)_(3)]^(2+)/S_(2)O_(8)2-/light system and S_(2) O_(8)^(2-)/light system were compared for the first time.In the nonphotosensitizer system,1 shows bifunctional roles and acts as optical absorption center and active catalytic site,and oxygen evolution rate is lower and it takes longer time.In the photosensitizer system,1 only acts as a catalyst,the photosensitizer enhances the light absorption and promotes water oxidation reaction with higher O_(2) yield and QE,meanwhile the photosensitizer brings the defect of high cost and instability into the system.Based on the results the two different reaction mechanisms were deeply discussed.展开更多
In the present work, the sulfur doped bismuth-based catalysts were prepared by incipient wetness impregnation method and used for the hydrochlorination of acetylene to vinyl chloride monomer （VCM） in a fixed-bed rea...In the present work, the sulfur doped bismuth-based catalysts were prepared by incipient wetness impregnation method and used for the hydrochlorination of acetylene to vinyl chloride monomer （VCM） in a fixed-bed reactor. The effect of introduction of S was characterized by N2 adsorption-desorption, powder X-ray diffraction, transmission electron microscopy, thermogravimetric analysis, temperature-programmed reduction and X-ray photoelectron spectroscopy. The characterization results indicated that the doping of S resulted in the increase of Brunauer-Emmett-Teller （BET） surface areas and decrease of active species particle size for the Bi-based catalysts, which led to more accessible active sites, and consequently boosted the catalytic hydrochlorination activity. The effect of H2SO4 concentration on the activity of this type catalyst was examined, and the results showed that there is an optimal loading of H2SO4 （S/Bi=0.5 mol/mol）, at which the conversion of C2H2 was enhanced to 81% under the reaction condition and coke deposition is a main reason for the deactivation of catalyst.展开更多
In our previous study,polyurethane(PU)based multilayer films assembled with weak polyelectrolytes exhibited controllable loading and release properties,but would be decomposed in high salt solution.Herein,a strong pol...In our previous study,polyurethane(PU)based multilayer films assembled with weak polyelectrolytes exhibited controllable loading and release properties,but would be decomposed in high salt solution.Herein,a strong polyelectrolyte,poly(styrene sulfonic acid)sodium(PSS),was introduced to fabricate multilayer films.The salt tolerance of the film was investigated by evaluating the loading and release profiles towards model drug in salt solution with different concentrations.Results showed that the release behavior of the film,as well as its loading capacity,can be tuned by varying the salt concentrations.And the film showed a good salt tolerance that can remain integrity even after 6 cycles of drug loading and release in 600 mmol•L^(−1) NaCl solution.It showed that the salt tolerance of PU based films can be greatly improved through assembling with strong polyelectrolyte.展开更多
基金the funding support from the National Natural Science Foundation of China(No.21861035)the University Scientific Research Project of Xinjiang Uyghur Autonomous Region(No.XJEDU2017I001)。
文摘The photocatalytic performances of water oxidation were usually carried out in two different systems,photosensitizer and non-photosensitizer systems.There is few report about the same catalyst used in two systems and therefore it is of great significant to compare its role of the same catalyst in two systems and explore its different reaction mechanisms.In this work,first 4 kinds of metallic Co microparticles were obtained by different reduction methods through hydrothermal processes,and Co@Co_(3)O_(4) coreshell microparticles(1-4)were obtained from these metallic Co microparticles oxidized in air or in the reacting solution in situ.The core-shell structure of 1 was characterized by a series of analytical techniques.1-4 exhibited excellent activities and stabilities in the[Ru(bpy)3]^(2+)/S_(2) O_(8)^(2-)/light system when they were used as catalysts for the photocata lytic water oxidation.The maximum O2 evolution of 1 after 20 min’s illumination was 98.2 pmol,the O_(2) yield was 65.5%,the initial turnover frequency was 6.6×10^(-3),the initial quantum efficiency(ΦQYinitial)was 15.0%higher than Co(8.3%),CoO(11.7%),Co_(2)O_(3)(1.2%),Co_(3)O_(4)(2.8%)and 5(2.2%).Even after the sixth run,the catalytic activity of recovered 1 still remained 85.1%of initial activity.In addition,the photocatalytic performances of 1 in the[Ru(bpy)_(3)]^(2+)/S_(2)O_(8)2-/light system and S_(2) O_(8)^(2-)/light system were compared for the first time.In the nonphotosensitizer system,1 shows bifunctional roles and acts as optical absorption center and active catalytic site,and oxygen evolution rate is lower and it takes longer time.In the photosensitizer system,1 only acts as a catalyst,the photosensitizer enhances the light absorption and promotes water oxidation reaction with higher O_(2) yield and QE,meanwhile the photosensitizer brings the defect of high cost and instability into the system.Based on the results the two different reaction mechanisms were deeply discussed.
基金supported by the National Natural Science Foundation of China(Nos.U1403293,21263025)the Graduate Research and Innovation Program of Xinjiang(No.XJGRI2015010)
文摘In the present work, the sulfur doped bismuth-based catalysts were prepared by incipient wetness impregnation method and used for the hydrochlorination of acetylene to vinyl chloride monomer （VCM） in a fixed-bed reactor. The effect of introduction of S was characterized by N2 adsorption-desorption, powder X-ray diffraction, transmission electron microscopy, thermogravimetric analysis, temperature-programmed reduction and X-ray photoelectron spectroscopy. The characterization results indicated that the doping of S resulted in the increase of Brunauer-Emmett-Teller （BET） surface areas and decrease of active species particle size for the Bi-based catalysts, which led to more accessible active sites, and consequently boosted the catalytic hydrochlorination activity. The effect of H2SO4 concentration on the activity of this type catalyst was examined, and the results showed that there is an optimal loading of H2SO4 （S/Bi=0.5 mol/mol）, at which the conversion of C2H2 was enhanced to 81% under the reaction condition and coke deposition is a main reason for the deactivation of catalyst.
基金Financial supports for this work were provided from Natural Science Foundation of China(No.51163015)the Program for New Century Excellent Talents in University(NCET-11-1072)Graduate Student Research Innovation Project of Xinjiang(No.XJGRI2013019).
文摘In our previous study,polyurethane(PU)based multilayer films assembled with weak polyelectrolytes exhibited controllable loading and release properties,but would be decomposed in high salt solution.Herein,a strong polyelectrolyte,poly(styrene sulfonic acid)sodium(PSS),was introduced to fabricate multilayer films.The salt tolerance of the film was investigated by evaluating the loading and release profiles towards model drug in salt solution with different concentrations.Results showed that the release behavior of the film,as well as its loading capacity,can be tuned by varying the salt concentrations.And the film showed a good salt tolerance that can remain integrity even after 6 cycles of drug loading and release in 600 mmol•L^(−1) NaCl solution.It showed that the salt tolerance of PU based films can be greatly improved through assembling with strong polyelectrolyte.
