Spillover of active oxygen intermediates of binary RuO/NbO nanowires for highly active and robust acidic oxygen evolution.

Over-oxidation of surface ruthenium active sites of RuO-based electrocatalysts leads to the formation of soluble high-valent Ru species and subsequent structural collapse of electrocatalysts, which results in their low stability for the acidic oxygen evolution reaction (OER). Herein, a binary RuO/NbO electrocatalyst with abundant and intimate interfaces has been rationally designed and synthesized to enhance its OER activity in acidic electrolyte, delivering a low overpotential of 179 mV at 10 mA cm, a small Tafel slope of 73 mV dec, and a stabilized catalytic durability over a period of 750 h. Extensive experiments have demonstrated that the spillover of active oxygen intermediates from RuO to NbO and the subsequent participation of lattice oxygen of NbO instead of RuO for the acidic OER suppressed the over-oxidation of surface ruthenium species and thereby improved the catalytic stability of the binary electrocatalysts.