Phase engineering oriented defect-rich amorphous/crystalline RuO₂ nanoporous particles for boosting oxygen evolution reaction in acid media

Imposing phase engineering to porous materials is promising to realize outperforming electrocatalytic performances by taking advantages of the merits of porous nanoarchitecture and heterophase structure. In this work, amorphous/crystalline ruthenium oxide (RuO₂) porous particles with rationally regulated heterophases are successfully prepared by integrating the phase engineering into the porous material synthesis. The resultant defect-rich amorphous/crystalline RuO₂ porous particles exhibit excellent electrocatalytic performance toward the oxygen evolution reaction, achieving a low overpotential of 165 mV at a current density of 10 mA·cm⁻² and a high mass activity up to 133.8 mA·cm⁻² at a low overpotential of 200 mV. This work indicates that the synergistic effect of amorphous/crystalline heterophase and porous structural characteristics enables RuO₂ to trigger a superior electrocatalytic activity.