Electron donation from carbon support enhances the activity and stability of ultrasmall ruthenium dioxide...

Developing non-iridium (Ir)-based electrocatalysts with good stability and activity for acid oxygen evolution reaction (OER) is of great importance for electrocatalytic water splitting. Ruthenium dioxide (RuO₂), which has lower price and higher OER activity, has been recognized as an attractive alternative to Ir-based electrocatalyst for acidic OER. However, the stability of most Ru-based electrocatalysts faces a great challenge in acidic condition. Here, a highly stable and active RuO₂-based catalyst, tiny RuO₂ nanoparticles inlaid onto carbon support (RuO₂/C), is successfully prepared for acidic OER. Such a structure can efficiently inhibit the over-growth of RuO₂ nanoparticles and prevent the agglomeration of RuO₂ nanoparticles. Moreover, it is found that carbon support donate electron to RuO₂ nanoparticles, which enhances the OER activity and stability of RuO₂ during acidic OER. The RuO₂/C exhibits an impressive OER performance with a low overpotential (197 mV at 10 mA cm^-2) and low degradation rate (0.035 mV h^-1) over a 450-h stability test in 0.5 M H₂SO₄, which are much better than the commercial Ir/C, RuO₂ and the reported Ru-based electrocatalysts. This work provides an efficient strategy to simultaneously improve both stability and activity of Ru-based catalysts for acidic water oxidation.