Publications by authors named "Vasileios Kyriakou"
A novel oxygen evolution reaction (OER) electrocatalyst was prepared by a synthesis strategy consisting of the solvothermal growth of NiS nanostructures on Ni foam, followed by hydrothermal incorporation of Fe species (Fe-NiS/Ni foam). This electrocatalyst displayed a low OER overpotential of 230 mV at 100 mA·cm, a low Tafel slope of 43 mV·dec, and constant performance at an industrially relevant current density (500 mA·cm) over 100 h in a 1.0 M KOH electrolyte, despite a minor loss of Fe in the process.
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- - Perovskite oxides with dispersed nanoparticles are vital for energy conversion and catalysis, and redox exsolution offers a way to create nanostructures directly on these oxide supports through reduction methods.
- - A novel method using plasma exposure has been developed for nucleating nanoparticles on perovskite, which outperforms traditional hydrogen reduction by producing over ten times more nickel nanoparticles from lanthanum titanate.
- - Unlike electrochemical methods, plasma does not need a specialized cell setup and can be used on various materials, additionally, nitrogen plasma helps remove oxygen from the lattice, creating important chemical intermediates that enhance its effectiveness.
Understanding and controlling the formation of nanoparticles at the surface of functional oxide supports is critical for tuning activity and stability for catalytic and energy conversion applications. Here, we use a latest generation environmental transmission electron microscope to follow the exsolution of individual nanoparticles at the surface of perovskite oxides, with ultrahigh spatial and temporal resolution. Qualitative and quantitative analysis of the data reveals the atomic scale processes that underpin the formation of the socketed, strain-inducing interface that confers exsolved particles their exceptional stability and reactivity.
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