A novel mixed-valent heterometallic pentanuclear CoⅢ3 CoⅡ Dy Ⅲ cluster has been rationally assembled taking advantage of a bifunctional ligand with o-vanillin and tripodal tris(hydroxymethyl)aminomethane units. This unique heterometallic cluster represents a rare example of T-shaped molecules exhibiting slow magnetic relaxation.
Supercapacitors(SCs) have attracted much attention as one of the alternative energy devices due to their high power performance,long cycle life,and low maintenance cost.Graphene is considered as an innovative and promising material due to its large theoretical specific surface area,high electrical conductivity,good mechanical properties and chemical stability.Herein,we report an effective strategy for elaborately constructing rationally functionalized self-standing graphene(SG) obtained from giant graphene oxide(GGO) paper followed by an ultrarapid thermal-processing.This treatment results in both the exfoliation of graphene sheets and the reduction of GGO by elimination of oxygencontaining groups.The as-prepared SG electrode materials without additive and conducting agent provide an excellent combination of the electrical double layer capacitor(EDLC) and pseudocapacitor(PC) functions and exhibit superior electrochemical performance,including high specific capacitance,good rate capability and excellent cycling stability when investigated in three-electrode electrochemical cells.
The effect of Ce/La misch metal addition on the microstructural evolution of as-cast and as-soluted Mg-5.3Zn-0.5Ca(wt.%) alloys was systematically investigated. It was found that Ce/La could effectively refine the as-cast alloy and restrain grain growth during solution treatment, which was derived from the constitutional supercooling during solidification process and the formation of stable intermetallic compounds Ce Mg12 and Mg17La2. Furthermore, Ce/La microalloying and solution treatment resulted in an evolution from the original lamellar Ca2Mg6Zn3/α-Mg to the divorced eutectic structure. The thermal stability of Mg-Zn-Ca alloy could be effectively improved by Ce/La addition, because the low-melting-point binary Mg-Zn phase was transformed to Mg x Zn y-Ca-(Ce/La) phase with higher thermal stability and the amount of Ca2Mg6Zn3/α-Mg eutectic structure was reduced.
