Mg micro/nanoscale materials with sphere-like morphologies: Size-controlled synthesis and characterization

Abstract

Mg micro/nanoscale materials with sphere-like morphologies are prepared via a vapor-transport deposition process. The structure and morphology of the as-prepared products are characterized by powder X-ray diffraction and scanning electron microscopy. Vapor-liquid-solid mechanism is proposed to explain the formation of Mg micro/nanospheres on the basis of the experimental results. magnesium, micro/nanoscale spheres, growth mechanismThe search for clean and renewable energy sources is an urgent target because of energy crisis and environmental concerns [1][2][3][4][5] . As important parts of the renewable energy, hydrogen energy and fuel cells have attracted a lot of research interest all over the world [6][7][8][9][10][11] . Hydrogen storage materials are the key technology for the utilization of hydrogen energy, and they are made attractive in recent years [12][13][14] . For practical applications, hydrogen storage materials should exhibit high hydrogen capacity, low absorption/desorption temperatures and pressures, and fast kinetics and thermodynamics for the hydriding/ dehydriding process. To satisfy the requirement for the usage, many researches have focused on various hydrogen storage materials, including metal hydrides, complex hydrides, porous solids (such as carbon-based materials, and metal-organic frameworks (MOFs)) [15,16] . Among these materials, metallic Mg has a lot of merits for hydrogen storage: high storage capacity (7.6% by weight by forming MgH 2 ), low density (1.74 g/cm 3 ), abundance in the earth's crust, and low cost. However, the main disadvantage of traditional bulk Mg/MgH 2 is the slow kinetics of hydrogen uptake and release, and the relatively high operation temperature (approximately 300℃).Actually, magnesium resources are very abundant in China, making it meaningful to develop the utilization of magnesium. With regards to micro/nanoscale structures, magnesium materials are expected to display intriguing physical and chemical properties [17][18][19][20][21][22][23] , paving a good way for overcoming those drawbacks of bulk Mg. In our previous work, we have exploited the synthesis of magnesium nano/mesoscale materials with different shape and the investigation of properties in hydrogen storage and Mg/air batteries, in which nano/meso Mg shows an excellent performance for storage and conversion of energy [22,23] . In this work, sphere-like Mg micro/nanoscale structures have been further achieved via vaportransport approach by adjusting the experimental parameters on the basis of our reported results. The research on the Mg products with uniform morphologies may provide new opportunities for the controlled synthesis of these materials at a high yield and then promote the potential use in hydrogen storage and fuel cells.

Size Control in the Colloidal Synthesis of Plasmonic Magnesium Nanoparticles

“…These methods are often expensive, time consuming, and can result in poor crystallinity that degrades the plasmonic response. Alternatively, gas-phase methods provide good size and shape control − but with low yields and extensive aggregation . In contrast, colloidal NP syntheses are inexpensive, facile, scalable, and have the potential for substantial size and shape control, as has been demonstrated extensively for Au and Ag. − …”

Magnesium microspheres and nanospheres: Morphology-controlled synthesis and application in Mg/MnO2 batteries

“…For the preparation of Mg micro/nanoscale materials, the vapor-deposition apparatus the experimental procedures, and parameters were similar to that used in our previous work at an evaporation temperature of 825 o C in argon atmosphere [13], except for changing the deposition temperature at 240, 270, and 300 o C on the substrate, which was a stainless steel screen mesh (material: 316L) for collecting the depositing samples. Detailed experimental parameters are summarized in [11].…”