Titanium oxynitride-supported Ru nanoparticles as exceptional electrocatalysts for alkaline hydrogen evolution reaction
Milutin Smiljanić, Marjan Bele, Luka Pavko, Armin Hrnjić, Francisco Ruiz‐Zepeda, Lazar Bijelić, Ana Rebeka Kamšek, Mejrema Nuhanović, Aleš Marsel, Lea Gašparič, Anton Kokalj, Nejc Hodnik
Abstract
We present a novel and highly efficient catalyst for the hydrogen evolution reaction (HER) consisting of low-loaded Ru nanoparticles dispersed on a titanium oxynitride-graphene oxide (Ru/TiON-C) support. Ru/TiON-C with a Ru loading of only 6 wt% is significantly more active for HER in alkaline media than the Ru/C analog. More importantly, Ru/TiON-C outperforms the Pt/C benchmark both intrinsically (2.5 times higher turnover frequency) and in terms of metal utilization (4.5 times higher mass activity). The exceptional HER activity of Ru/TiON-C is related to the metal-support interaction (MSI) induced by TiON, which was experimentally evidenced by X-ray photoelectron spectroscopy and further investigated by density functional theory calculations. It can be proposed that MSI enhances water dissociation properties and tunes hydrogen adsorption energy at Ru active sites, while stability is provided by the strong anchoring of the Ru nanoparticles on the TiON. The presented strategy to develop advanced electrocatalytic composites can be extended to other metallic active sites and electrochemical reactions.