Isolated\nOctahedral Pt-Induced Electron Transfer to\nUltralow-Content Ruthenium-Doped Spinel Co<sub>3</sub>O<sub>4</sub> for Enhanced Acidic Overall Water Splitting

The\ndevelopment of a highly active and stable oxygen evolution\nreaction (OER) electrocatalyst is desirable for sustainable and efficient\nhydrogen production via proton exchange membrane water electrolysis\n(PEMWE) powered by renewable electricity yet challenging. Herein,\nwe report a robust Pt/Ru-codoped spinel cobalt oxide (PtRu–Co<sub>3</sub>O<sub>4</sub>) electrocatalyst with an ultralow precious metal\nloading for acidic overall water splitting. PtRu–Co<sub>3</sub>O<sub>4</sub> exhibits excellent catalytic activity (1.63 V at 100\nmA cm<sup>–2</sup>) and outstanding stability without significant\nperformance degradation for 100 h operation. Experimental analysis\nand theoretical calculations indicate that Pt doping can induce electron\ntransfer to Ru-doped Co<sub>3</sub>O<sub>4</sub>, optimize the absorption\nenergy of oxygen intermediates, and stabilize metal–oxygen\nbonds, thus enhancing the catalytic performance through an adsorbate-evolving\nmechanism. As a consequence, the PEM electrolyzer featuring PtRu–Co<sub>3</sub>O<sub>4</sub> catalyst with low precious metal mass loading\nof 0.23 mg cm<sup>–2</sup> can drive a current density of 1.0\nA cm<sup>–2</sup> at 1.83 V, revealing great promise for the\napplication of noniridium-based catalysts with low contents of precious\nmetal for hydrogen production.