Ultrathin Carbon Coating and Defect Engineering Promote RuO2 as an Efficient Catalyst for Acidic Oxygen Evolution Reaction with Super-High Durability

Developing acid-stable electrocatalysts with high activity for the oxygen evolution reaction (OER) is of paramount importance for many energy-related technologies. This work reports that ultrathin nitrogen-doped carbon coated oxygen-vacancy (Vo center dot) rich RuO2 nanoparticles on carbon nanotubes (CNTs) (NC@Vo center dot-RuO2/CNTs-350), synthesized through the controlled calcination in air, is an efficient acid-stable electrocatalyst for the OER. It only needs an overpotential of 170.0 mV to drive 10.0 mA cm(-2) and shows excellent stability with no distinguishable activity loss observed for >900 h. Its mass activity is >110 times higher than the commercial RuO2. In particular, an electrolyzer assembled with this catalyst shows a record-low cell voltage of 1.45 V to deliver 10.0 mA cm(-2) and exhibits a low performance drop for >1000 h. The NC@Vo center dot-RuO2/CNTs-350 also shows super-high catalytic activities and excellent stabilities for OER in neutral and alkaline media. DFT calculations indicate that its high catalytic activity mainly arises from the strong electronic coupling between RuO2 and NC/CNTs, which increases the oxidation state and catalytic activity of Ru at the active site and improves the stabilities of lattice oxygen and surface Ru during the OER processes. The presence of Vo center dot can strengthen the electronic coupling between RuO2 and NC/CNTs.

Automated summary

This work reports the synthesis of ultrathin nitrogen-doped carbon coated oxygen-vacancy rich RuO2 nanoparticles on carbon nanotubes as an efficient and acid-stable electrocatalyst for the oxygen evolution reaction. It exhibits high activity and excellent stability, surpassing the commercial RuO2 catalyst. The presence of oxygen vacancies strengthens the electronic coupling and enhances catalytic activity.