Magnesium isotopic compositions are reported for twenty-four international geological reference materials including igneous, metamorphic and sedimentary rocks, as well as phlogopite and serpentine minerals. The longterm reproducibility of Mg isotopic determination, based on 4-year analyses of olivine and seawater samples, was ≤ 0.07‰ (2s) for d 26 Mg and ≤ 0.05‰ (2s) for d 25 Mg. Accuracy was tested by analysis of synthetic reference materials down to the quoted long-term reproducibility. This comprehensive dataset, plus seawater data produced in the same laboratory, serves as a reference for quality assurance and inter-laboratory comparison of high-precision Mg isotopic data.Significant advances have been made on Mg isotope geochemistry over the past decade. It was debated whether or not the Earth has a chondritic Mg isotopic composition. The most recent studies indicate that the Earth, as well as the Moon, have Mg isotopic composition similar to chondrites within 0.07‰ (2s) in 26 Mg/ 24 Mg ratio (Teng et al.
Reduced
graphene oxide (rGO) and NiO composites were prepared with
an environmentally friendly method, in which hydrogen gas was employed
as the reducing agent to convert reduced graphene oxides. Our study
indicates that the success of this new approach is because NiO not
only is an additive of the composites but also acts as a catalyst
to facilitate the reduction. Characterization with scanning electron
microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared
spectroscopy, and X-ray powder diffraction illustrates that the as-prepared
rGO/NiO composites have a three-dimensional flowerlike hierarchical
structure, which prevents graphene from taking face to face aggregation
and therefore greatly improves the stability of the composite materials.
A hybrid capacitor electrode made of the NiO/rGO composites shows
great performance, in which the maximum specific capacitance is close
to 428 F g–1 at a discharge current density of 0.38
A g–1 in a 6.0 M KOH electrolyte.
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