A core–shell TiON–C nanostructure as a self-supported and scalable electrode for fast oxygen evolution reaction in acidic media

Abstract A novel self-supported architecture, based on carbon nanofibers homogeneously coated by an ultrathin TiON layer and functionalized by a fine dispersion of Ir nanoparticles (NPs) with ultralow loading (60 μ g * cm ⁻² with particle size ≈1.5 nm), is presented as a potential anode for proton exchange membrane electrolysis cells. This structure serves as an ideal anode for rapid electrochemical oxygen evolution reaction in acidic conditions. It combines the high conductivity of the carbon-TiON core–shell structure, the chemical stability of the TiON thin layer to protect C against corrosion, and the enhanced mass activity of Ir NPs. Additionally, it offers excellent mechanical stability and a straightforward, scalable fabrication process. The electrochemical activity (80 mA cm ⁻² /1.2 mA * µ g _Ir ⁻¹ @ 1.6 V) outperforms C–Ir and Ir-black references. Preliminary long-term test are carried out and strategies for a potential improvement of the long-term stability are critically discussed.