pH-Universal Electro-Splitting of Water Enabled by Pit-Rich Ultrathin Ru and RuO₂ Nanoplates

Electrochemical water splitting is a clean technology for hydrogen generation; however, the deliberate fabrication of exceptionally active and long-term stable electrocatalysts capable of operating under pH-universal conditions remains a formidable obstacle. In this work, we demonstrate a simple method to achieve ultrathin nanoplates (NPs) for enhanced water-splitting electrocatalysis. The as-prepared Ru NPs feature an ultrathin structure with abundant pits and exhibit excellent catalytic performance toward the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in pH-universal environments. The Ru NPs were heat-treated at 250 °C and denoted as Ru NPs-250 °C. With synthesized Ru NPs-250 °C as the anode and reference Ru NPs as the cathode, the electrolytic cell drives overall water splitting at 10 mA cm^-2, requiring applied cell potentials of 1.48 V (0.5 M H₂SO₄), 1.53 V (0.05 M H₂SO₄), 1.50 V (1 M KOH), and 1.51 V (0.1 M KOH). The values are considerably superior to those of the commercial IrO₂-Pt/C electrolyzer. Furthermore, the Ru NPs-250 °C-Ru NPs electrolyzer maintains robust stability during extended electrolysis, exhibiting its great potential for practical water-splitting applications.