Carbonized polymer dots enabled the construction of Ru-RuO₂ Interface for efficient overall water splitting

Developing high-performance hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) electrocatalysts to accelerate water splitting kinetics is essential for advancing electrolytic hydrogen production. Herein, a Ru-RuO₂ heterostructure catalyst with stabilized active interfaces is developed by utilizing carbonized polymer dots (CPDs) as electron-modulating mediators. Specifically, CPDs serve as electron reservoir that dynamically regulate the valence state of Ru through coupling with Ru sites during the reduction-oxidation process, driving the oriented formation of small-sized, high-density Ru-RuO₂ nano-heterojunction structure. Simultaneously, CPDs' nanoscale template effect synergistically induces abundant nanoporous structures with Ru-RuO₂ species. The dual modification of geometric and electronic properties not only achieves efficient charge separation but also optimizes bifunctional active sites and significantly improves mass transfer performance. The resultant Ru-RuO₂/CPDs catalyst successfully integrates the advantages of HER and OER active components, achieving highly efficient and stable bifunctional catalytic activity. In overall water splitting devices, the Ru-RuO₂/CPDs catalyst exhibits cell voltages of merely 1.51 V in H₂SO₄ and 1.44 V in 1.0 M KOH to achieve 10 mA cm^-2, with both systems demonstrating stability exceeding 220 h. This work provides a facile strategy for designing efficient and stable catalysts for water splitting across a broad pH range.