The photoreduction of CO_(2)to achieve high-value-added hydrocarbons under simulated sunlight irradiation is advantageous,but challenging.In this study,a series of MgO and Au nanoparticle-co-modified g-C_(3)N_(4)photo...The photoreduction of CO_(2)to achieve high-value-added hydrocarbons under simulated sunlight irradiation is advantageous,but challenging.In this study,a series of MgO and Au nanoparticle-co-modified g-C_(3)N_(4)photocatalysts were synthesized and subsequently applied for the photocatalytic reduction of CO_(2)with H2O under simulated solar irradiation.The best photocatalytic performance was demonstrated by the Au and 3%MgO-co-modified g-C_(3)N_(4)photocatalysts with CO,CH_(4),CH3OH,and CH3CHO yields of 423.9,83.2,47.2,and 130.4μmol/g,respectively,in a 3-h reaction.We investigated the effects of MgO and Au as cocatalysts on photocatalytic behaviors,respectively.The characterizations and experimental results showed that the enhanced photocatalytic activity was due to the synergistic effect among the components of the ternary photocatalyst.The cocatalyst MgO can activate CO_(2)(adsorbed at the interface between the MgO and Au particles),and the Mg-N bonds formed in the MgO-CN nanosheets played an important role in the charge transfer.Meanwhile,the Au particles that were modified into MgO/g-C_(3)N_(4)can increase the absorption of visible light via the surface plasmon resonance effect and further reduce the activation energies of the photoreduction of CO_(2)using H2O.This study provided an effective method for the modification of traditional primary photocatalysts with promising performance for photocatalytic CO_(2)reduction.展开更多
Au-Ag bimetallic nanoparticle‐supported microporous titanium silicalite‐1catalysts were prepared via a hydrothermal‐immersion method,and their structures were examined.These materials serve as efficient catalysts f...Au-Ag bimetallic nanoparticle‐supported microporous titanium silicalite‐1catalysts were prepared via a hydrothermal‐immersion method,and their structures were examined.These materials serve as efficient catalysts for the photosynthesis of propylene oxide via the epoxidation of propene.The Au/Ag mass ratio and reaction temperature were demonstrated to have significant effects on the catalytic activity and selectivity of propylene oxide.The optimal formation rate(68.3μmol/g·h)and selectivity(52.3%)toward propylene oxide were achieved with an Au:Ag mass ratio of4:1.Notably,the strong synergistic effect between Au and Ag resulted in superior photocatalysis of the bimetallic systems compared with those of the individual systems.A probable reaction mechanism was proposed based on the theoretical and experimental results.展开更多
Metal-free graphitic carbon nitride(g-C_(3)N_(4))has captured significant attention as a low-cost and efficient hydrogen production photocatalyst through.Effectively regulating the microstructure and accelerating the ...Metal-free graphitic carbon nitride(g-C_(3)N_(4))has captured significant attention as a low-cost and efficient hydrogen production photocatalyst through.Effectively regulating the microstructure and accelerating the separation of photogenerated carriers remain crucial strategies for promoting the photocatalytic performance of this material.Herein,a novel sulfur–carbon co-doped g-C_(3)N_(4)(SCCN)hierarchical microtubules filled with abundant nanosheets inside by thermal polymerization is reported.Numerous nanosheets create abundant pores and cavities inside the SCCN microtubes,thereby increasing the specific surface area of g-C_(3)N_(4)and providing sufficient reactant attachment sites.Besides,the hierarchical structure of SCCN microtubules strengthens the reflection and scattering of light,and the utilization of visible light is favorably affected.More importantly,co-doping S and C has greatly improved the photocatalytic performance of graphitic carbon nitride,optimized the band gap structure and enhanced the photogenerated carrier splitting.Consequently,the SCCN exhibits a remarkable photocatalytic H_(2)evolution rate of 4868μmol/(g·h).This work demonstrates the potential of multi-nonmetal doped g-C_(3)N_(4)as the ideal photocatalyst for H2 evolution.展开更多
Developing highly efficient bifunctional cathode and anode electrocatalysts is very important for the large-scale application of direct formic acid fuel cells. However, the high-cost and poor CO-tolera nee ability of ...Developing highly efficient bifunctional cathode and anode electrocatalysts is very important for the large-scale application of direct formic acid fuel cells. However, the high-cost and poor CO-tolera nee ability of the most commonly used Pt greatly block this process. To in crease the utilizatio n efficie ncy and exte nd bifunctional properties of precious Pt, herei n, coral-like Pt3Ag nano crystals are developed as an excelle nt bifunctional electrocatalyst through a facile one-pot solvothermal method. The formation mechanism of Ptgg nanocorals has been elaborated well via a series of control experiments. It is proved that 1-naphthol serving as a guiding surfactant plays a key role in the formation of high-quality nano corals. Thanks to the unique coral-like structure and alloy effects, the developed Ptgg nano corals present sign ificantly enhanced electrocatalytic properties (including activity, stability and CO-toleranee ability) towards both the cathodic oxygen reduction and anodic formic acid oxidati on, as compared with those of commercial Pt black and Pt-based nan oparticles. The prese nt synthetic method can also be extended to fabricate other bimetallic electrocatalysts with unique morphology and structure.展开更多
The development of highly efficient and stable Pd-based catalysts is crucial to improve their sluggish oxygen reduction reaction(ORR)kinetics in acid media.To improve ORR activity and utilization efficiency of Pd,an i...The development of highly efficient and stable Pd-based catalysts is crucial to improve their sluggish oxygen reduction reaction(ORR)kinetics in acid media.To improve ORR activity and utilization efficiency of Pd,an ideal catalyst should have ORR-favorable chemical environment,optimized geometric structure,and long periods of operation.In this work,we first synthesize a novel trimetallic Au@PdPb core–shell catalyst consisting of PdPb alloy nano-layers grown on the surface of ultrathin Au nanowires(NWs)by a two-step water-bath method.The Au@PdPb NWs have the merits of anisotropic one-dimensional nanostructure,high utilization efficiency of Pd atoms and doping of Pb atoms.Because of the structural and multiple compositional advantages,Au@PdPb NWs exhibit remarkably enhanced ORR activity with a high haIf-wave potential(0.827 V),much better than those of commercial Pd black(0.788 V)and bimetallic Au@Pd NWs(0.803 V).Moreover,Au@PdPb NWs display better electrocatalytic stability for the ORR than those of Pd black and Au@Pd NWs.This study demonstrates the validity of our approach for deriving highly ORR-active Pd-based catalysts by modifying their structure and composition.展开更多
We fabricate a novel cellulose acetate （CA） ultrafiltration membrane modified by block copolymer F127-b- PDMAEMA, which is synthesized using F127 and DMAEMA via the ARGET ATRP method. Compared to conven- tional ultr...We fabricate a novel cellulose acetate （CA） ultrafiltration membrane modified by block copolymer F127-b- PDMAEMA, which is synthesized using F127 and DMAEMA via the ARGET ATRP method. Compared to conven- tional ultrafiltration membranes, the incorporation of both F 127 and PDMAEMA can not only readily increase the hydrophilicity of the membrane, but also exhibit stimuli-responsiveness to temperature and pH. Fourier transform infrared spectroscopy （FT-IR）, nuclear magnetic resonance spectroscopy （NMR）, and gel permeation chromatog- raphy （GPC） are employed to analyze the structure of the F 127-b-PDMAEMA. The membrane properties are eval- uated via scanning electron microscope （SEM） imaging, porosity test, automatic target recognition Fourier trans- form infrared spectroscopy （ATR-FTIR）, water contact angle test and permeation test. The results indicate that the F 127-b-PDMAEMA is an excellent pore agent, which contributes to an enhancement of the membrane in sensitivity to temperature and pH. The modified membrane also exhibits lower water contact angle （64.5~）, which is attributed to the good anti-fouling performance and high water permeation.展开更多
The large-scale industrial production of acetic acid (HAc) from carbonylation of methanol has enabled intense research interest from direct hydrogenation of HAc to acetaldehyde (AA).Herein,a series of cerium-iron oxid...The large-scale industrial production of acetic acid (HAc) from carbonylation of methanol has enabled intense research interest from direct hydrogenation of HAc to acetaldehyde (AA).Herein,a series of cerium-iron oxide solid solution supported metallic cobalt catalysts were prepared by modified sol-gel method and were applied in gas-phase hydrogenation of HAc to AA.A synergistic effect between the hydrogenation metal cobalt and Ce-Fe oxide solid solution is revealed.Specifically,oxygen vacancies provide the active sites for adsorption of HAc,while highly uniformly dispersed metallic Co adsorbs H2 and activates the reduction of HAc into AA.Moreover,the metallic Co can also assist the cyclical conversion between Fe3+/Fe2+ and Ce3+/Ce4+ on the surface of Ce1.xFexO2-δ supports.The unique effect substantially enhances the ability of the support material to rapidly capture oxygen atoms from HAc.It is found that the catalyst of 5% Co/Ce0.8Fe0.2O2-δ with the highest concentration of oxygen vacancy presents the best catalytic performance (i.e.acetaldehyde yield reaches 49.9%) under the optimal reaction conditions (i.e.623 K and H2 flow rate =10 mL/min).This work indicates that the Co/Ce-Fe oxide solid solution catalyst can be potentially used for the selective hydrogenation from HAc to AA.The synergy between the metallic Co and Ce1-xFexO2-δ revealed can be extended to the design of other composite catalysts.展开更多
Conductive polymer fibers/wires(CPFs)are important materials in modern technologies due to their unique one-dimension geometry,electrical conductivity,and flexibility.However,the advanced applications of current CPFs ...Conductive polymer fibers/wires(CPFs)are important materials in modern technologies due to their unique one-dimension geometry,electrical conductivity,and flexibility.However,the advanced applications of current CPFs are limited by their low electrical conductivities(<500 S/m)and poor interfacial interactions between conductive fllers(e.g.,graphite)and polymers.Therefore,in current electrical applications,metal wires/foils like copper and aluminum are the most frequently utilized conductive fibers/wires instead of the inferior conductive CPFs.This work successfully addresses the heavy phase segregation between polymers and conductive inorganic materials to obtain semiliquid metal polymer fibers(SLMPFs)which exhibit an ultrahigh electrical conductivity(over 10^(6)S/m),remarkable thermal processability,and considerable mechanical performance(Young's modulus:~300 MPa).Semiliquid metal(gallium-tin alloy)with tunable viscosities is the key to achieve the excellent miscibility between metals and polymers.Both the rheological results and numerical simulations demonstrate the critical viscosity matching for the successfui preparation of the fibers.More importantly,the fibers are adapted with classic polymer melt-processing like melt injection,which indicates the scalable production of the highly conductive fibers.The SLMPFs are highly promising substitutes for metal wires/fbers in modern electrical applications such as electricity transmission,data communication,and underwater works.展开更多
Conductive polymer fibers/wires(CPFs)are important materials in modern technologies due to their unique one-dimension geometry,electrical conductivity,and flexibility.
文摘The photoreduction of CO_(2)to achieve high-value-added hydrocarbons under simulated sunlight irradiation is advantageous,but challenging.In this study,a series of MgO and Au nanoparticle-co-modified g-C_(3)N_(4)photocatalysts were synthesized and subsequently applied for the photocatalytic reduction of CO_(2)with H2O under simulated solar irradiation.The best photocatalytic performance was demonstrated by the Au and 3%MgO-co-modified g-C_(3)N_(4)photocatalysts with CO,CH_(4),CH3OH,and CH3CHO yields of 423.9,83.2,47.2,and 130.4μmol/g,respectively,in a 3-h reaction.We investigated the effects of MgO and Au as cocatalysts on photocatalytic behaviors,respectively.The characterizations and experimental results showed that the enhanced photocatalytic activity was due to the synergistic effect among the components of the ternary photocatalyst.The cocatalyst MgO can activate CO_(2)(adsorbed at the interface between the MgO and Au particles),and the Mg-N bonds formed in the MgO-CN nanosheets played an important role in the charge transfer.Meanwhile,the Au particles that were modified into MgO/g-C_(3)N_(4)can increase the absorption of visible light via the surface plasmon resonance effect and further reduce the activation energies of the photoreduction of CO_(2)using H2O.This study provided an effective method for the modification of traditional primary photocatalysts with promising performance for photocatalytic CO_(2)reduction.
基金supported by the National Natural Science Foundation of China(21576050)the Natural Science Foundation of Jiangsu Province(BK20150604)~~
文摘Au-Ag bimetallic nanoparticle‐supported microporous titanium silicalite‐1catalysts were prepared via a hydrothermal‐immersion method,and their structures were examined.These materials serve as efficient catalysts for the photosynthesis of propylene oxide via the epoxidation of propene.The Au/Ag mass ratio and reaction temperature were demonstrated to have significant effects on the catalytic activity and selectivity of propylene oxide.The optimal formation rate(68.3μmol/g·h)and selectivity(52.3%)toward propylene oxide were achieved with an Au:Ag mass ratio of4:1.Notably,the strong synergistic effect between Au and Ag resulted in superior photocatalysis of the bimetallic systems compared with those of the individual systems.A probable reaction mechanism was proposed based on the theoretical and experimental results.
基金supported by the National Natural Science Foundation of China(Grant No.22078057)the National Natural Science Foundation of China(Key Program of Joint Fund,Grant No.U22A20435)+1 种基金the Fundamental Research Funds for the Central Universities(Grant No.2242023K5001)the Scientific and Technological Innovation Project of Carbon Emission Peak and Carbon Neutrality of Jiangsu Province(Grant No.BK20220001).
文摘Metal-free graphitic carbon nitride(g-C_(3)N_(4))has captured significant attention as a low-cost and efficient hydrogen production photocatalyst through.Effectively regulating the microstructure and accelerating the separation of photogenerated carriers remain crucial strategies for promoting the photocatalytic performance of this material.Herein,a novel sulfur–carbon co-doped g-C_(3)N_(4)(SCCN)hierarchical microtubules filled with abundant nanosheets inside by thermal polymerization is reported.Numerous nanosheets create abundant pores and cavities inside the SCCN microtubes,thereby increasing the specific surface area of g-C_(3)N_(4)and providing sufficient reactant attachment sites.Besides,the hierarchical structure of SCCN microtubules strengthens the reflection and scattering of light,and the utilization of visible light is favorably affected.More importantly,co-doping S and C has greatly improved the photocatalytic performance of graphitic carbon nitride,optimized the band gap structure and enhanced the photogenerated carrier splitting.Consequently,the SCCN exhibits a remarkable photocatalytic H_(2)evolution rate of 4868μmol/(g·h).This work demonstrates the potential of multi-nonmetal doped g-C_(3)N_(4)as the ideal photocatalyst for H2 evolution.
基金the National Natural Science Foundation of China (Nos. 21576139, 21875112, 21576050 and 51602052)Jiangsu Provincial Natural Science Foundation of China (No. BK20150604)+1 种基金National and Local Joint Engineering Research Center of Biomedical Functional MaterialsPriority Academic Program Development of Jiangsu Higher Education Institutions.
文摘Developing highly efficient bifunctional cathode and anode electrocatalysts is very important for the large-scale application of direct formic acid fuel cells. However, the high-cost and poor CO-tolera nee ability of the most commonly used Pt greatly block this process. To in crease the utilizatio n efficie ncy and exte nd bifunctional properties of precious Pt, herei n, coral-like Pt3Ag nano crystals are developed as an excelle nt bifunctional electrocatalyst through a facile one-pot solvothermal method. The formation mechanism of Ptgg nanocorals has been elaborated well via a series of control experiments. It is proved that 1-naphthol serving as a guiding surfactant plays a key role in the formation of high-quality nano corals. Thanks to the unique coral-like structure and alloy effects, the developed Ptgg nano corals present sign ificantly enhanced electrocatalytic properties (including activity, stability and CO-toleranee ability) towards both the cathodic oxygen reduction and anodic formic acid oxidati on, as compared with those of commercial Pt black and Pt-based nan oparticles. The prese nt synthetic method can also be extended to fabricate other bimetallic electrocatalysts with unique morphology and structure.
基金supported by the Academic Research Fund(AcRF)Tier 1 Grant(No.RG105/19)from the Ministry of Education in Singapore,the National Natural Science Foundation of China(No.21875112)and the China Scholarship Council(No.201906090199).
文摘The development of highly efficient and stable Pd-based catalysts is crucial to improve their sluggish oxygen reduction reaction(ORR)kinetics in acid media.To improve ORR activity and utilization efficiency of Pd,an ideal catalyst should have ORR-favorable chemical environment,optimized geometric structure,and long periods of operation.In this work,we first synthesize a novel trimetallic Au@PdPb core–shell catalyst consisting of PdPb alloy nano-layers grown on the surface of ultrathin Au nanowires(NWs)by a two-step water-bath method.The Au@PdPb NWs have the merits of anisotropic one-dimensional nanostructure,high utilization efficiency of Pd atoms and doping of Pb atoms.Because of the structural and multiple compositional advantages,Au@PdPb NWs exhibit remarkably enhanced ORR activity with a high haIf-wave potential(0.827 V),much better than those of commercial Pd black(0.788 V)and bimetallic Au@Pd NWs(0.803 V).Moreover,Au@PdPb NWs display better electrocatalytic stability for the ORR than those of Pd black and Au@Pd NWs.This study demonstrates the validity of our approach for deriving highly ORR-active Pd-based catalysts by modifying their structure and composition.
基金This work was financially supported by the Funda- mental Research Funds for the Central Universities of China （Nos. 3207045403, 3207045409）, National Natu- ral Science Foundation of China （Nos. 21576050, 51602052）, Jiangsu Provincial Natural Science Founda- tion of China （No. BK20150604） and a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions （PAPD）.
文摘We fabricate a novel cellulose acetate （CA） ultrafiltration membrane modified by block copolymer F127-b- PDMAEMA, which is synthesized using F127 and DMAEMA via the ARGET ATRP method. Compared to conven- tional ultrafiltration membranes, the incorporation of both F 127 and PDMAEMA can not only readily increase the hydrophilicity of the membrane, but also exhibit stimuli-responsiveness to temperature and pH. Fourier transform infrared spectroscopy （FT-IR）, nuclear magnetic resonance spectroscopy （NMR）, and gel permeation chromatog- raphy （GPC） are employed to analyze the structure of the F 127-b-PDMAEMA. The membrane properties are eval- uated via scanning electron microscope （SEM） imaging, porosity test, automatic target recognition Fourier trans- form infrared spectroscopy （ATR-FTIR）, water contact angle test and permeation test. The results indicate that the F 127-b-PDMAEMA is an excellent pore agent, which contributes to an enhancement of the membrane in sensitivity to temperature and pH. The modified membrane also exhibits lower water contact angle （64.5~）, which is attributed to the good anti-fouling performance and high water permeation.
基金This work was financially supported by the National Natural Science Foundation of China (Nos. 21576050 and 51602052)the Jiangsu Provincial Natural Science Foundation of China (BK20150604)+2 种基金the Fundamental Research Funds for the Central Universities of China (Nos. 3207045403,3207045409, 3207046414)Foundation of Jiangsu Key Laboratory for Biomass Energy and Material (JSBEM201805)Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD) and Zhongying Young Scholars of Southeast University.
文摘The large-scale industrial production of acetic acid (HAc) from carbonylation of methanol has enabled intense research interest from direct hydrogenation of HAc to acetaldehyde (AA).Herein,a series of cerium-iron oxide solid solution supported metallic cobalt catalysts were prepared by modified sol-gel method and were applied in gas-phase hydrogenation of HAc to AA.A synergistic effect between the hydrogenation metal cobalt and Ce-Fe oxide solid solution is revealed.Specifically,oxygen vacancies provide the active sites for adsorption of HAc,while highly uniformly dispersed metallic Co adsorbs H2 and activates the reduction of HAc into AA.Moreover,the metallic Co can also assist the cyclical conversion between Fe3+/Fe2+ and Ce3+/Ce4+ on the surface of Ce1.xFexO2-δ supports.The unique effect substantially enhances the ability of the support material to rapidly capture oxygen atoms from HAc.It is found that the catalyst of 5% Co/Ce0.8Fe0.2O2-δ with the highest concentration of oxygen vacancy presents the best catalytic performance (i.e.acetaldehyde yield reaches 49.9%) under the optimal reaction conditions (i.e.623 K and H2 flow rate =10 mL/min).This work indicates that the Co/Ce-Fe oxide solid solution catalyst can be potentially used for the selective hydrogenation from HAc to AA.The synergy between the metallic Co and Ce1-xFexO2-δ revealed can be extended to the design of other composite catalysts.
基金supported by the National Natural Science Foundation of China(grant number 52173249,Jiuyang Zhang).
文摘Conductive polymer fibers/wires(CPFs)are important materials in modern technologies due to their unique one-dimension geometry,electrical conductivity,and flexibility.However,the advanced applications of current CPFs are limited by their low electrical conductivities(<500 S/m)and poor interfacial interactions between conductive fllers(e.g.,graphite)and polymers.Therefore,in current electrical applications,metal wires/foils like copper and aluminum are the most frequently utilized conductive fibers/wires instead of the inferior conductive CPFs.This work successfully addresses the heavy phase segregation between polymers and conductive inorganic materials to obtain semiliquid metal polymer fibers(SLMPFs)which exhibit an ultrahigh electrical conductivity(over 10^(6)S/m),remarkable thermal processability,and considerable mechanical performance(Young's modulus:~300 MPa).Semiliquid metal(gallium-tin alloy)with tunable viscosities is the key to achieve the excellent miscibility between metals and polymers.Both the rheological results and numerical simulations demonstrate the critical viscosity matching for the successfui preparation of the fibers.More importantly,the fibers are adapted with classic polymer melt-processing like melt injection,which indicates the scalable production of the highly conductive fibers.The SLMPFs are highly promising substitutes for metal wires/fbers in modern electrical applications such as electricity transmission,data communication,and underwater works.
基金This work was supported by the National Natural Science Foundation of China(grant number 52173249,Jiuyang Zhang).
文摘Conductive polymer fibers/wires(CPFs)are important materials in modern technologies due to their unique one-dimension geometry,electrical conductivity,and flexibility.
