Defect-rich ruthenium dioxide electrocatalyst enabled by electronic reservoir effect of carbonized polymer dot for remarkable pH-universal oxygen evolution

Designing highly active and durable electrocatalysts for oxygen evolution reaction (OER) over a wide pH range is of great significance, but it remains challenging. Herein, a defect-rich RuO2 electrocatalyst with pH-universal OER activity is developed by rationally utilizing the electronic reservoir effect of Mn-coordinated carbonized polymer dots (Mn-CPDs). Mn-CPDs as distinct electron acceptor/donor endows Ru-O sites of RuO2 with abundant defective structures (i.e., O-Ru-O-Ru-Ru sites and O-Ru-O-Mn units) via reduction-oxidation processes, with incorporated Mn atoms simultaneously feeding electron to Ru. The resultant Ru-O-Mn/CPD exhibits an ultralow OER potential of 196 mV, 194 mV and 251 mV at 10 mA·cm−2 under 0.5 M H2SO4, 1.0 M KOH, and 1.0 M PBS media, respectively, and long-term catalytic stability, which are among the best OER electrocatalysts. Surprisingly, Ru-O-Mn/CPD also shows great Pt-like hydrogen evolution activity. The theoretical simulation indicates that defective Ru-O-Mn structures produce electron-rich Ru region and near-optimal Ru-4d/O-2p band center, thus optimizing the adsorption/desorption kinetics of key intermediates.