Highly efficient and stable bifunctional electrocatalysts that can be used for large-current-density electrolysis of alkaline seawater are highly desirable for carbon-neutral economies,but their facile and controllabl...Highly efficient and stable bifunctional electrocatalysts that can be used for large-current-density electrolysis of alkaline seawater are highly desirable for carbon-neutral economies,but their facile and controllable synthesis remains a challenge.Here,self-assembled ultralow Ru,Ni-doped Fe_(2)O_(3) with a lily shaped morphology was synthesized on iron foam(RuNi-Fe_(2)O_(3)/IF)via a facile one-step hydrothermal process,in which the intact lily shaped RuNi-Fe_(2)O_(3)/IF was obtained by adjusting the ratio of Ru/Ni.Benefitting from the Ru/Ni chemical substitution,the as-synthesized RuNi-Fe_(2)O_(3)/IF can act as free-standing dual-function electrodes that are applied to electrocatalysis for the hydrogen evolution(HER)and oxygen evolution reactions(OER)in 1.0 mol L^(-1) KOH,requiring an overpotential of 75.0 mV to drive 100 mA cm^(-2) for HER and 329.0 mV for OER.Moreover,the overall water splitting catalyzed by RuNi-Fe_(2)O_(3)/IF only demands ultralow cell voltages of 1.66 and 1.73 V to drive 100 mA cm^(-2) in 1.0 mol L^(-1) KOH and 1.0 mol L^(-1) KOH seawater electrolytes,respectively.The electrodes show remarkable long-term durability,maintaining current densities exceeding 100 mA cm^(-2) for more than 100 h and thus outperforming the two-electrode system composed of noble catalysts.This work provides an efficient,economical method to synthesize self-standing bifunctional electrodes for large-current-density alkaline seawater electrolysis,which is of significant importance for ecological protection and energy exploitation.展开更多
Highly active Ir‐La‐S/AC catalyst was successfully prepared by co‐impregnation of an activated carbon（AC） carrier with a sulfuric acid solution of Ir and La species and compared with a tradition‐ally prepared Ir...Highly active Ir‐La‐S/AC catalyst was successfully prepared by co‐impregnation of an activated carbon（AC） carrier with a sulfuric acid solution of Ir and La species and compared with a tradition‐ally prepared Ir‐La/AC catalyst. High angle annular dark‐field‐scanning transmission electron mi‐croscopy（HAADF‐STEM） measurement results show that most of the Ir species on Ir‐La‐S/AC exist as single atomic sites, while those on Ir‐La/AC exist as nanoparticles with an average diameter of 1.5 nm. Evaluation of Ir‐La‐S/AC as a catalyst for heterogeneous carbonylation of methanol to acetyl gave a maximum TOF （turn‐over‐frequency） of 2760 h^–1, which was distinctly higher than that achieved by the Ir‐La/AC catalyst（approximately 1000 h^-1）. Temperature‐programmed desorption of ammonia（NH3‐TPD） result shows that the addition of sulfuric acid during the preparation pro‐cedure results in significantly more acidic sites on Ir‐La‐S/AC than those on Ir‐La/AC, which plays a key role in the enhancement of CO insertion as the rate‐determining step. Tempera‐ture‐programmed reduction（TPR） and in situ X‐ray photoelectron spectroscopy reveal that Ir spe‐cies are more reducible, and that more Ir^＋ might be formed by activation of Ir‐La‐S/AC than those on the Ir‐La/AC catalyst, which is thought to be beneficial for reductive elimination of AcI from Ir^3＋ species as an essential step for CH3I regeneration and acetyl formation.展开更多
Signcryption, which was introduced by ZHEN~ is a cryptographic primitive that fulfils the functions of both digital signature and encryption and guarantees confidentiality, integrity and non-repudiation in a more effi...Signcryption, which was introduced by ZHEN~ is a cryptographic primitive that fulfils the functions of both digital signature and encryption and guarantees confidentiality, integrity and non-repudiation in a more effi- cient way. Certificateless signcryption and pro- xy signcryption in identity-based cryptography were proposed for different applications. Most of these schemes are constructed by bilinear pairings from elliptic curves. However, some schemes were recently presented without pai- rings. In this paper, we present a certificateless proxy identity-based signcryption scheme with- out bilinear pairings, which is efficient and secure.展开更多
The fast excitation system of a composite magnetic controllable reactor is introduced. In this excitation system, a bidirectional function （i.e. fast forward excitation and backward forcible demagnetization） is avai...The fast excitation system of a composite magnetic controllable reactor is introduced. In this excitation system, a bidirectional function （i.e. fast forward excitation and backward forcible demagnetization） is available, which can significantly improve the response speed, performances, and application scope of magnetic controllable reactor.展开更多
A series of ammonium-bifunctionalized ionic liquid extractants （ammonium-Bif-ILEs） combined with a number of anions, in- cluding carboxylic acids and 1,3-diketonates, have been prepared and studied in this report. T...A series of ammonium-bifunctionalized ionic liquid extractants （ammonium-Bif-ILEs） combined with a number of anions, in- cluding carboxylic acids and 1,3-diketonates, have been prepared and studied in this report. Their extraction behavior and properties toward rare earth ions （REs（III）） are systematically investigated in chloride media as a function of important param- eters such as aqueous phase pH, salting-out agent concentrations, and extraction temperature. The separation performance of ammonium-Bif-ILEs toward REs（III） are systematically discussed. The results demonstrate that ammonium-Bif-ILEs have a synergistic effect between the cation and anions in separation of REs（III）. The influences of different anions on separation fac- tor （β） values are further studied. By comparison, ammonium-Bif-ILEs containing 1,3-diketonates have more potential appli- cations in La（III）/RE（III） separation than those containing carboxylic acids.展开更多
Design and development of efficient non-viral gene delivery systems is critical to overcome various barriers for effective intracellular gene delivery.Eight new spermine-based protonatable surfactants were designed,sy...Design and development of efficient non-viral gene delivery systems is critical to overcome various barriers for effective intracellular gene delivery.Eight new spermine-based protonatable surfactants were designed,synthesized and evaluated as non-viral pH-sensitive gene carriers.These carriers formed stable complexes with plasmid DNA at an N/P ratio as low as 2.The sizes of the carrier/pDNA nanoparticles (N/P = 12) were in the range of 90–130 nm,smaller than that of Lipofectamine2000/pDNA nanoparticles.The pDNA nanoparticles of the carriers exhibited substantially increased hemolysis when pH decreased from 7.4 to 5.5.The DNA nanoparticles had low cytotocixity,similar to that of Lipofectamine-2000/pDNA nanoparticles.The pH-sensitive gene carriers with no helper lipids resulted in much higher intracellular transfection and gene expression in U87 cells than Lipofectamine-2000.[N,N′-Bis(oleoylcysteinyl)(β-alanyl-α-lysyl)]-spermine monoamide (SKACO) resulted in the highest luciferase transfection efficiency,more than 400 times higher than that of Lipofectamine-2000,and GFP expression in 71% of transfected U87 cells.SKACO was identified as a promising lead carrier for efficient gene delivery.These spermine-based pH-sensitive amphiphilic carriers have a potential to be further developed as efficient non-viral multifunctional gene delivery systems.展开更多
Surface patterning is very useful in biomaterial studies, yet it is not easy to prepare a micropattern with cell-adhesion contrast that is stable in a wet environment. Recently, a platform technique of transfer photol...Surface patterning is very useful in biomaterial studies, yet it is not easy to prepare a micropattern with cell-adhesion contrast that is stable in a wet environment. Recently, a platform technique of transfer photolithography was invented to fabricate stable metal microarrays on the surface of a cell-adhesion resistant and mechanically biomimetic poly（ethylene glycol） hydrogel; the linker is the key chemical in such a transfer strategy. This article reports the design and synthesis of a hetero-bifunctional macromonomer linker with a thiol group at one end and an acryloyl group at the other end. The bifunctional linker was char- acterized by GPC and ~H NMR, and the average number of thiol groups in the bifunctional linker was detected by Ellman＇s reagent. The regent stability under wet conditions was also confirmed by the model reactants. The resultant micropatterned surfaces are meaningful for future studies of cell behaviors on mechanically biomimetic matrixes.展开更多
Developing high-performance bifunctional catalysts toward hydrogen evolution reaction(HER) and oxygen evolution reaction(OER) is essential to enhance water splitting efficiency for large-scale hydrogen production. Nei...Developing high-performance bifunctional catalysts toward hydrogen evolution reaction(HER) and oxygen evolution reaction(OER) is essential to enhance water splitting efficiency for large-scale hydrogen production. Neither noble metal Pt nor transition metal compounds show satisfactory performances for both HER and OER simultaneously. Here, we prepared a three-dimensional Pt-Ni3 Se2@NiOOH/NF(PNOF) hybrid catalyst via in-situ growth strategy. Benefitting from the self-supported structure and oxygen vacancies on the surface of NiOOH nanosheets, the PNOF electrode shows remarkably catalytic performance for dual HER and OER. The overall water electrolyzer using PNOF as anode and cathode can achieve a current density of10 mA cm^-2 at a low voltage of 1.52 V with excellent long-term stability, which is superior to precious metal catalysts of Pt/C and Ir/C. This study provides a promising strategy for preparing bifunctional catalysts with high performance.展开更多
文摘Highly efficient and stable bifunctional electrocatalysts that can be used for large-current-density electrolysis of alkaline seawater are highly desirable for carbon-neutral economies,but their facile and controllable synthesis remains a challenge.Here,self-assembled ultralow Ru,Ni-doped Fe_(2)O_(3) with a lily shaped morphology was synthesized on iron foam(RuNi-Fe_(2)O_(3)/IF)via a facile one-step hydrothermal process,in which the intact lily shaped RuNi-Fe_(2)O_(3)/IF was obtained by adjusting the ratio of Ru/Ni.Benefitting from the Ru/Ni chemical substitution,the as-synthesized RuNi-Fe_(2)O_(3)/IF can act as free-standing dual-function electrodes that are applied to electrocatalysis for the hydrogen evolution(HER)and oxygen evolution reactions(OER)in 1.0 mol L^(-1) KOH,requiring an overpotential of 75.0 mV to drive 100 mA cm^(-2) for HER and 329.0 mV for OER.Moreover,the overall water splitting catalyzed by RuNi-Fe_(2)O_(3)/IF only demands ultralow cell voltages of 1.66 and 1.73 V to drive 100 mA cm^(-2) in 1.0 mol L^(-1) KOH and 1.0 mol L^(-1) KOH seawater electrolytes,respectively.The electrodes show remarkable long-term durability,maintaining current densities exceeding 100 mA cm^(-2) for more than 100 h and thus outperforming the two-electrode system composed of noble catalysts.This work provides an efficient,economical method to synthesize self-standing bifunctional electrodes for large-current-density alkaline seawater electrolysis,which is of significant importance for ecological protection and energy exploitation.
基金supported by the National Key R&D Program of China (2017YFB0602203)~~
文摘Highly active Ir‐La‐S/AC catalyst was successfully prepared by co‐impregnation of an activated carbon（AC） carrier with a sulfuric acid solution of Ir and La species and compared with a tradition‐ally prepared Ir‐La/AC catalyst. High angle annular dark‐field‐scanning transmission electron mi‐croscopy（HAADF‐STEM） measurement results show that most of the Ir species on Ir‐La‐S/AC exist as single atomic sites, while those on Ir‐La/AC exist as nanoparticles with an average diameter of 1.5 nm. Evaluation of Ir‐La‐S/AC as a catalyst for heterogeneous carbonylation of methanol to acetyl gave a maximum TOF （turn‐over‐frequency） of 2760 h^–1, which was distinctly higher than that achieved by the Ir‐La/AC catalyst（approximately 1000 h^-1）. Temperature‐programmed desorption of ammonia（NH3‐TPD） result shows that the addition of sulfuric acid during the preparation pro‐cedure results in significantly more acidic sites on Ir‐La‐S/AC than those on Ir‐La/AC, which plays a key role in the enhancement of CO insertion as the rate‐determining step. Tempera‐ture‐programmed reduction（TPR） and in situ X‐ray photoelectron spectroscopy reveal that Ir spe‐cies are more reducible, and that more Ir^＋ might be formed by activation of Ir‐La‐S/AC than those on the Ir‐La/AC catalyst, which is thought to be beneficial for reductive elimination of AcI from Ir^3＋ species as an essential step for CH3I regeneration and acetyl formation.
基金supported by the National Natural Science Foundation of China under Grants No.61272499,No.10990011
文摘Signcryption, which was introduced by ZHEN~ is a cryptographic primitive that fulfils the functions of both digital signature and encryption and guarantees confidentiality, integrity and non-repudiation in a more effi- cient way. Certificateless signcryption and pro- xy signcryption in identity-based cryptography were proposed for different applications. Most of these schemes are constructed by bilinear pairings from elliptic curves. However, some schemes were recently presented without pai- rings. In this paper, we present a certificateless proxy identity-based signcryption scheme with- out bilinear pairings, which is efficient and secure.
文摘The fast excitation system of a composite magnetic controllable reactor is introduced. In this excitation system, a bidirectional function （i.e. fast forward excitation and backward forcible demagnetization） is available, which can significantly improve the response speed, performances, and application scope of magnetic controllable reactor.
基金supported by the National Basic Research Program of China (2012CBA01202)the National Natural Science Foundation of China (51174184, 21401110)+1 种基金the Key Research Program of the Chinese Academy of Sciences (KGZD-EW-201-1)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China (14KJB150019)
文摘A series of ammonium-bifunctionalized ionic liquid extractants （ammonium-Bif-ILEs） combined with a number of anions, in- cluding carboxylic acids and 1,3-diketonates, have been prepared and studied in this report. Their extraction behavior and properties toward rare earth ions （REs（III）） are systematically investigated in chloride media as a function of important param- eters such as aqueous phase pH, salting-out agent concentrations, and extraction temperature. The separation performance of ammonium-Bif-ILEs toward REs（III） are systematically discussed. The results demonstrate that ammonium-Bif-ILEs have a synergistic effect between the cation and anions in separation of REs（III）. The influences of different anions on separation fac- tor （β） values are further studied. By comparison, ammonium-Bif-ILEs containing 1,3-diketonates have more potential appli- cations in La（III）/RE（III） separation than those containing carboxylic acids.
文摘Design and development of efficient non-viral gene delivery systems is critical to overcome various barriers for effective intracellular gene delivery.Eight new spermine-based protonatable surfactants were designed,synthesized and evaluated as non-viral pH-sensitive gene carriers.These carriers formed stable complexes with plasmid DNA at an N/P ratio as low as 2.The sizes of the carrier/pDNA nanoparticles (N/P = 12) were in the range of 90–130 nm,smaller than that of Lipofectamine2000/pDNA nanoparticles.The pDNA nanoparticles of the carriers exhibited substantially increased hemolysis when pH decreased from 7.4 to 5.5.The DNA nanoparticles had low cytotocixity,similar to that of Lipofectamine-2000/pDNA nanoparticles.The pH-sensitive gene carriers with no helper lipids resulted in much higher intracellular transfection and gene expression in U87 cells than Lipofectamine-2000.[N,N′-Bis(oleoylcysteinyl)(β-alanyl-α-lysyl)]-spermine monoamide (SKACO) resulted in the highest luciferase transfection efficiency,more than 400 times higher than that of Lipofectamine-2000,and GFP expression in 71% of transfected U87 cells.SKACO was identified as a promising lead carrier for efficient gene delivery.These spermine-based pH-sensitive amphiphilic carriers have a potential to be further developed as efficient non-viral multifunctional gene delivery systems.
基金supported by the National Natural Science Foundation of China(21034002,91127028,51273046)the Ministry of Science and Technology of China(2011CB606203)the Science and Technology Development Foundation of Shanghai(13XD1401000)
文摘Surface patterning is very useful in biomaterial studies, yet it is not easy to prepare a micropattern with cell-adhesion contrast that is stable in a wet environment. Recently, a platform technique of transfer photolithography was invented to fabricate stable metal microarrays on the surface of a cell-adhesion resistant and mechanically biomimetic poly（ethylene glycol） hydrogel; the linker is the key chemical in such a transfer strategy. This article reports the design and synthesis of a hetero-bifunctional macromonomer linker with a thiol group at one end and an acryloyl group at the other end. The bifunctional linker was char- acterized by GPC and ~H NMR, and the average number of thiol groups in the bifunctional linker was detected by Ellman＇s reagent. The regent stability under wet conditions was also confirmed by the model reactants. The resultant micropatterned surfaces are meaningful for future studies of cell behaviors on mechanically biomimetic matrixes.
基金supported by the National Natural Science Foundation of China(51804216,51472178 and U1601216)Tianjin Natural Science Foundation(16JCYBJC17600)and Shen-zhen Science and Technology Foundation(JCYJ20170307145703486)
文摘Developing high-performance bifunctional catalysts toward hydrogen evolution reaction(HER) and oxygen evolution reaction(OER) is essential to enhance water splitting efficiency for large-scale hydrogen production. Neither noble metal Pt nor transition metal compounds show satisfactory performances for both HER and OER simultaneously. Here, we prepared a three-dimensional Pt-Ni3 Se2@NiOOH/NF(PNOF) hybrid catalyst via in-situ growth strategy. Benefitting from the self-supported structure and oxygen vacancies on the surface of NiOOH nanosheets, the PNOF electrode shows remarkably catalytic performance for dual HER and OER. The overall water electrolyzer using PNOF as anode and cathode can achieve a current density of10 mA cm^-2 at a low voltage of 1.52 V with excellent long-term stability, which is superior to precious metal catalysts of Pt/C and Ir/C. This study provides a promising strategy for preparing bifunctional catalysts with high performance.
