A Low‐Temperature Solid Chemistry to Ru Clusterrene for Scalable Hydrogen Production

Platinum-group-metal (PGM) nanomaterials are prominent in chemical and energy conversions. To date, their scalable manufacturing is confined by complex post-processing or high-temperature calcination (≥ 800°C), which are often required for conventional small-sized nanoparticles. Herein, we have successfully developed a thermal buffer-assisted low-temperature (250°C) calcination strategy to create a sub-nano Ru metallene called "Ru clusterrene" for anion exchange membrane water electrolysis (AEMWE). The rational use of NaCl is pivotal for successful synthesis, serving as a "buffer" to prevent thermal runaway. Consequently, the Ru clusterrene exhibits an ultra-thin, fluid-like structure that enables strong interaction with the substrate and ensures maximized active site exposure. Importantly, this strategy costs only US$39.42/g_Ru, which is substantially lower than that of commercial Ru/C (Premetek, US$1407.50/g_Ru). The Ru clusterrene delivers an outstanding activity of 1.73 V@2 A cm^‒2 and 2.0 V@5.4 A cm^‒2, as well as an unprecedented stability for 1000 h at 2 A cm^‒2 (80°C) and 3500 h at 1 A cm^‒2 (50°C). More significantly, it exhibits a high stack performance in AEMWE (3.6 V@1 A cm^‒2 and 2000 h@25 A), representing the most advanced level for AEMWE cathode catalyst.