The utilization of nickel-based catalysts as alternatives to expensive platinum-based(Pt-based)materials for the hydrogen evolution reaction in acidic electrolytes has attracted considerable attention due to their pot...The utilization of nickel-based catalysts as alternatives to expensive platinum-based(Pt-based)materials for the hydrogen evolution reaction in acidic electrolytes has attracted considerable attention due to their potential for enabling cost-effective industrial applications.However,the unsatisfied cyclic stability and electrochemical activity limit their further application.In this work,nickel-molybdenum(Ni-Mo)alloy catalysts were successfully synthesized through a comprehensive process including electrodeposition,thermal annealing,and electrochemical activation.Owing to the synergistic interaction of molybdenum trinickelide(Ni_(3)Mo)and molybdenum dioxide(MoO_(2))in Ni-Mo alloy,the catalyst display superior overall electrochemical properties.A low overpotential of 86 mV at 10 mA/cm^(2)and a Tafel slope of 74.0 mV/dec in 0.5 mol/L H_(2)SO_(4)solution can be achieved.Notably,remarkable stability with negligible performance degradation even after 100 h could be maintained.This work presents a novel and effective strategy for the design and fabrication of high-performance,non-precious metal electrocatalysts for acidic water electrolysis.展开更多
Interfacial adhesion between carbon fibers(CF)and polyetherketoneketone(PEKK)is a key factor that affects the mechanical performances of their composites.It is therefore of great importance to impregnate the CF bundle...Interfacial adhesion between carbon fibers(CF)and polyetherketoneketone(PEKK)is a key factor that affects the mechanical performances of their composites.It is therefore of great importance to impregnate the CF bundles with PEKK as effi-ciently as possible.We report that PEKK with a good dispersion in a mixed solution of 4-chlorophenol and 1,2-dichloroethane can be introduced onto CF surfaces by solution impregnation and curing at 280,320,340 and 360℃.The excellent wettability or infiltra-tion of the PEKK solution guarantees a full covering and its tight binding to CFs,making it possible to evaluate the interfacial shear strength(IFSS)with the microdroplet method.The interior of the CF bundles is completely and uniformly filled with PEKK by solu-tion impregnation,leading to a high interlaminar shear strength(ILSS).The maximum IFSS and ILSS reached 107.8 and 99.3 MPa,respectively.Such superior shear properties are ascribed to the formation of amorphous PEKK in the small spaces between CFs.展开更多
Because of its high purity and excellent orientation, mesophase pitch is a superior precursor for high-performance car-bon materials. However, the preparation of top-notch mesophase pitch faces challenges. Catalytic p...Because of its high purity and excellent orientation, mesophase pitch is a superior precursor for high-performance car-bon materials. However, the preparation of top-notch mesophase pitch faces challenges. Catalytic polycondensation at low temperat-ures is more favorable for synthesizing mesophase pitch, because it circumvents the high-temperature free radical reaction of other thermal polycondensation approaches. The reaction is gentle and can be easily controlled. It has the potential to significantly im-prove the yield of mesophase pitch and easily introduce naphthenic characteristics into the molecules, catalytic polycondensation is therefore a preferred method of synthesizing highly spinnable mesophase pitch. This review provides a synopsis of the selective pre-treatment of the raw materials to prepare different mesophase pitches, and explains the reaction mechanism and associated research advances for different catalytic systems in recent years. Finally, how to manufacture high-quality mesophase pitch by using a cata-lyst-promoter system is summarized and proposed, which may provide a theoretical basis for the future design of high-quality pitch molecules.展开更多
基金supported by the National Natural Science Foundation of China(22179138).
文摘The utilization of nickel-based catalysts as alternatives to expensive platinum-based(Pt-based)materials for the hydrogen evolution reaction in acidic electrolytes has attracted considerable attention due to their potential for enabling cost-effective industrial applications.However,the unsatisfied cyclic stability and electrochemical activity limit their further application.In this work,nickel-molybdenum(Ni-Mo)alloy catalysts were successfully synthesized through a comprehensive process including electrodeposition,thermal annealing,and electrochemical activation.Owing to the synergistic interaction of molybdenum trinickelide(Ni_(3)Mo)and molybdenum dioxide(MoO_(2))in Ni-Mo alloy,the catalyst display superior overall electrochemical properties.A low overpotential of 86 mV at 10 mA/cm^(2)and a Tafel slope of 74.0 mV/dec in 0.5 mol/L H_(2)SO_(4)solution can be achieved.Notably,remarkable stability with negligible performance degradation even after 100 h could be maintained.This work presents a novel and effective strategy for the design and fabrication of high-performance,non-precious metal electrocatalysts for acidic water electrolysis.
文摘Interfacial adhesion between carbon fibers(CF)and polyetherketoneketone(PEKK)is a key factor that affects the mechanical performances of their composites.It is therefore of great importance to impregnate the CF bundles with PEKK as effi-ciently as possible.We report that PEKK with a good dispersion in a mixed solution of 4-chlorophenol and 1,2-dichloroethane can be introduced onto CF surfaces by solution impregnation and curing at 280,320,340 and 360℃.The excellent wettability or infiltra-tion of the PEKK solution guarantees a full covering and its tight binding to CFs,making it possible to evaluate the interfacial shear strength(IFSS)with the microdroplet method.The interior of the CF bundles is completely and uniformly filled with PEKK by solu-tion impregnation,leading to a high interlaminar shear strength(ILSS).The maximum IFSS and ILSS reached 107.8 and 99.3 MPa,respectively.Such superior shear properties are ascribed to the formation of amorphous PEKK in the small spaces between CFs.
文摘Because of its high purity and excellent orientation, mesophase pitch is a superior precursor for high-performance car-bon materials. However, the preparation of top-notch mesophase pitch faces challenges. Catalytic polycondensation at low temperat-ures is more favorable for synthesizing mesophase pitch, because it circumvents the high-temperature free radical reaction of other thermal polycondensation approaches. The reaction is gentle and can be easily controlled. It has the potential to significantly im-prove the yield of mesophase pitch and easily introduce naphthenic characteristics into the molecules, catalytic polycondensation is therefore a preferred method of synthesizing highly spinnable mesophase pitch. This review provides a synopsis of the selective pre-treatment of the raw materials to prepare different mesophase pitches, and explains the reaction mechanism and associated research advances for different catalytic systems in recent years. Finally, how to manufacture high-quality mesophase pitch by using a cata-lyst-promoter system is summarized and proposed, which may provide a theoretical basis for the future design of high-quality pitch molecules.
