Chemical surface modification for the improvement of the hydrogenation kinetics and poisoning resistance of TiFe

Hydrogen storage performance of the TiFe-based materials suffers from difficulties with hydrogenation and sensitivity towards impurities in hydrogen gas reducing hydrogen uptake rates and decreasing the cycle stability. In present work the surface modification of the sintered Ti1.1Fe0.9Ox and arc-melted TiFe was performed using autocatalytic deposition of the Pd-based catalytic layers in order to achieve improvement of the H storage characteristics. Pd deposition proved to be efficient in significant facilitation of the hydrogenation ability of the materials at moderate H2 pressures and room temperature, even after their long exposure to air. Activation performance of the sintered Ti1.1Fe0.9Ox is superior than that for the arc-melted TiFe. This effect was associated with the presence of the oxygen-containing suboxide Ti4Fe2O1−x in the sintered sample acting as a hydrogen transfer catalyst. γ-Aminopropyltriethoxysilane pre-functionalization and subsequent Pd–P autocatalytic deposition onto the sintered Ti1.1Fe0.9Ox intermetallic substrate resulted in a better hydrogenation kinetics compared to the samples prepared by the conventional Pd deposition.

Research highlights
► Chemical surface modification of TiFe yields discontinuous deposits of Pd nanoparticles.
► The Pd deposition improves activation and H2 absorption in TiFe pre-exposed to air.
► Sintered Ti1.1Fe0.9Ox is characterised by better activation than arc-melted TiFe.