Nanoceria-Supported Ruthenium(0) Nanoparticles: Highly Active and Stable Catalysts for Hydrogen Evolution from Water.

Ruthenium(0) nanoparticles supported on nanoceria (Ru0 /CeO2 ) were prepared by reduction of Ru3+ ions on the surface of ceria using aqueous solution of NaBH4 . The Ru0 /CeO2 samples were characterized by advanced analytical tools and employed as electrocatalysts on the glassy carbon electrode (GCE) in hydrogen evolution from water. The GCE, modified by Ru0 /CeO2 (1.86 wt % Ru), provides an incredible electrocatalytic activity with a high exchange current density of 0.67 mA·cm-2 , low overpotential of 47 mV at j = 10 mA·cm-2 , and small Tafel slope of 41 mV·dec-1 . Moreover, this modified GCE provides an unprecedented long-term stability without changing the onset potential (33 mV) even after 10 000 scans in acidic water splitting at room temperature. The hydrogen gas, evolved during the water splitting using the Ru0 /CeO2 (1.86 wt % Ru) electrocatalyst, was also collected. The amount of the evolved H2 gas matches well with the calculated value, which indicates the achievement of nearly 100% Faradaic efficiency.