ALD of NiO and Pt on TiO₂ Nanotube Arrays Integrated into Titanium Porous Transport Layers for Dispersion Controlled Electrocatalysts

We present a tunable nanostructured material platform based on atomic layer deposition (ALD) of nickel oxide and platinum onto titania nanotube arrays (TiNT) embedded in a porous titanium web. The hierarchical architecture enables precise control over phase dispersion and interfacial chemistry, with NiO adopting predominantly Ni(OH)₂-like local environments and co-deposited Pt stabilized as highly dispersed species. ALD cycle tuning allows systematic modulation of oxide–metal interactions, providing a versatile framework for designing low-loading noble-metal catalysts. When applied to the hydrogen evolution reaction in alkaline media, these materials show enhanced activity driven by optimized NiOx coverage and improved Pt dispersion, achieving near-Pt performance at drastically reduced Pt loading. Tafel analysis confirms a Volmer–Heyrovsky pathway, with Ni(OH)₂ sites promoting proton transfer and facilitating hydrogen desorption at Pt. This work demonstrates how ALD-engineered embedded nanostructures can underpin next-generation electrocatalyst architectures.