Fabrication of Si nanopowder and application to hydrogen generation and photoluminescent material

Abstract

Si nanopowder is fabricated using the simple beads milling method. Fabricated Si nanopowder reacts with water in the neutral pH region between 7 and 9 to generate hydrogen. The hydrogen generation rate greatly increases with pH, while pH does not change after the hydrogen generation reaction. In the case of the reactions of Si nanopowder with strong alkaline solutions (eg pH13.9), 1600 mL hydrogen is generated from 1 g Si nanopowder in a short time (eg 15 min). When Si nanopowder is etched with HF solutions and immersed in ethanol, green photoluminescence (PL) is observed, and it is attributed to band-to-band transition of Si nanopowder. The Si nanopowder without HF etching in hexane shows blue PL. The PL spectra possess peaked structure, and it is attributed to vibronic bands of 9,10-dimethylantracene (DMA) in hexane solutions. The PL intensity is increased by more than 3,000 times by adsorption of DMA on Si nanopowder.

Electrochemical Preparation of Water-Reactive Silicon with Potential Applications in Hydrogen Generation

“…In fact, many researchers have reported and investigated the generation of H 2 by the reaction of nano-sized Si and pure water. [6][7][8][9][10][11][12][13][14][15] A video of the electrolyzed Si immersed in water at different temperatures can be viewed in the supplementary file (XY_Si_14 s.mov). These results clearly demonstrate that the electrolyzed Si is water-reactive, and that the reactivity is sensitive to the water temperature.…”

“…On-site generation of H 2 is of great interest in fuel cell applications. Researchers [6][7][8][9][10][11][12][13][14][15] have demonstrated H 2 generation by reacting silicon nanoparticles (Si NPs) with water. Since this reaction is thermodynamically spontaneous, an extremely large surface area of the nanoparticles kinetically facilitates the H 2 generation.…”

“…Ball mill is a simple approach, but it takes an extremely long time and the products are easily oxidized. 13 Since the first report by Nohira et al, 18 electrochemical reduction of solid SiO 2 in molten salts has attracted considerable attention. [19][20][21][22][23] The approach is applicable to the synthesis of Sibased materials for various applications.…”

New functional material: spark plasma sintered Si/SiO2 nanoparticles – fabrication and properties

“…4,14,19 Considering Si nanoparticle powders, one could mention milling techniques and plasma torches; however, these methods are not oen used for applications in optics. [23][24][25][26] In the present paper, we report on the results of fabricating a bulk material consisting of Si nanoclusters in an SiO 2 matrix. The material was fabricated by a spark plasma sintering (SPS) technique using oxidized silicon nanopowder.…”