Hydriding Chemical Vapor Deposition of Metal Hydride Nano-Fibers

Abstract

Here we show a novel chemical vapor synthesis technique, which uses high-pressure hydrogen and produces needle-shaped single crystalline made of metal hydride of MgH₂. The principle of this method is based on the gas phase reaction of vaporized metal with high pressure hydrogen sublimating into solid metal hydride (Mg(g) + H₂(g) → MgH₂(s)). This can directly produce pure single-phased metal hydride of MgH₂, while the conventional solid-gas reaction (Mg(s) + H₂(g) → MgH₂(s)) can hardly produce high purity hydride. The X-ray spectrum of as-synthesized product was MgH₂ with rutile structure. The scanning electron micrographs showed the interesting figure of the product; needle-shaped nano fibers with diameter less than 500 nm and length larger than 100 μm. Transmission electron micrograph and related electron diffraction pattern provided that the needle-shaped product was single crystalline of MgH₂ growing into [1 0 1] direction, into which Mg-layers and H-layers are alternately stacked up. The results appealed a revolutionary productive route for metal hydride, which offers many benefits for simplifying the productive procedure, minimizing processing time, saving energy, and upgrading the product.