Effect of surface morphology on initial hydrogen diffusion in vanadium alloys

The hydrogen absorption properties and diffusion behavior in V-3A alloys (V, V97Al3, V97Ru3) were studied by pressure-composition-temperature measurements and first-principles calculations. It was found that addition of Al and Ru could increase first plateau pressure. With the largest surface area among these alloy powders, V-3Ru achieved the highest hydrogen diffusivity at 433 K under an initial pressure of 1500 Pa. Hydrogen diffusion behaviors were examined by DFT calculations of barriers in both surface and internal cases of V-3A alloys. It revealed that initial diffusion rate was related to surface morphology. The results are expected to provide useful guidelines for understanding hydrogen absorption and diffusion properties of hydrogen storage materials. (C) 2019 Elsevier B.V. All rights reserved.