Abstract：NaAlH4(2at.% CeH2) + x at.% Ti31Cr15.5V45Fe8.5Ce0.5 (x = 0, 5, 10, 20, 30) composites were prepared by high energy ball-milling. Hydrogen desorption kinetics properties at 423K were studied. The results show that at the first desorption with the increasing of Ti31Cr15.5V45Fe8.5Ce0.5 content, hydrogen released increases and desorption time decreases. The hydrogen released increases from 1.89 wt.% to 2.31 wt.% and the time decreases from 45 min to 27.6 min when 30 at.% Ti31Cr15.5V45Fe8.5Ce0.5 added. X-ray Diffraction and Scanning Electron Microscopy results show that Ti31Cr15.5V45Fe8.5Ce0.5 is embedded on the surface of NaAlH4 particle in the form of hydride. The first step of desorption curves match to 3-dimensional diffusion model, indicates the rate-controlled step is hydrogen diffusion, the reaction rate constant increases as the Ti31Cr15.5V45Fe8.5Ce0.5 alloy content increases. It reveals that Ti31Cr15.5V45Fe8.5Ce0.5 hydride improves the hydrogen desorption performance by increasing the diffusion rate of hydrogen through the product layer.
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2019, Vol. 26 