Engineering Ru@Ir Core–Shell Nanoparticles on Titanium Oxynitride–Graphene Support for a Highly Active and Durable pH-Universal Hydrogen Evolution Reaction
Aleksandra Popović, Ivan Marić, Marjan Bele, Ervin Rems, Matej Huš, Luka Pavko, Francisco Ruiz‐Zepeda, Lazar Bijelić, Branimir Grgur, Nejc Hodnik, Milutin Smiljanić
Abstract
High Resolution Image Download MS PowerPoint Slide The rational design of electrocatalysts with high activity, durability, and low precious metal content is key to advancing hydrogen production via water electrolysis. Here, we present a multifunctional electrocatalyst based on Ru@Ir core–shell nanoparticles anchored on a conductive titanium oxynitride–graphene hybrid support (Ru@Ir/TiO x N y -C), achieving superior performance for the hydrogen evolution reaction (HER) in both acidic and alkaline media. The combination of the core–shell Ru@Ir architecture and the strong metal–support interaction (MSI) with TiO x N y optimizes hydrogen and hydroxide adsorption energies, as confirmed by X-ray photoelectron spectroscopy and density functional theory (DFT) calculations. In alkaline media, Ru@Ir/TiO x N y -C outperforms commercial Pt/C with a remarkably low overpotential of 13 mV at 10 mA cm –2 and high mass activity, while in acidic conditions, it rivals Pt/C and surpasses monometallic analogs. The long-term stability of the composite is attributed to the enhanced nanoparticle anchoring and structural integrity provided by the TiO x N y support. This work shows that combining core–shell nanostructures with engineered conductive supports can effectively replace platinum in HER applications. Such a nanocomposite strategy offers a versatile platform for the development of advanced electrocatalysts across a broad range of energy conversion reactions.