Enhancing the Interaction Between Pd Thin Films and Hydrogen via Atomic Stepped Interface Structures

Highly active interfaces are crucial to the hydrogen adsorption performance of nanomaterials. However, it remains challenging to conveniently and efficiently regulate atomic stacking characteristics. Here, we present a straightforward yet effective strategy for generating a high density of stepped atoms at the surface of thin films by controlling the migration behavior of sputtered atoms during deposition. Tuning sputtering power and substrate temperature yields wide-scale stepped interface structures, thus generating irregular conical columnar nanocrystals. Benefiting from the active and stable stepped atoms at the zigzag interface, the samples exhibit an excellent threshold pressure at 200 °C and a hydrogen adsorption of 110.06 cm3/g at 6 MPa, which is 2.2 times higher than that of conventional Pd thin films. Based on the control of nucleation and crystal growth during magnetron sputtering deposition, this method provides appropriate energy for surface atomic migration on columnar crystals, achieving high-density stepped interface structures. It can be readily extended to other substrates and noble metal systems, thus offering a novel strategy and guidance for the design of efficient and cost-effective hydrogen-interactive materials.