High-Rate Hydrogen Generation by Direct Sunlight Irradiation with a Triruthenium Complex

Herein we report a biomimetic triruthenium catalyst that, when under direct sunlight irradiation, facilitates high-rate H₂ production from formic acid (FA) dehydrogenation. The system consists of 2 μmol of catalyst and 6 μmol of tri- o-tolylphosphine in 1 mL of dimethylformamide (DMF) and 4 mL of FA/triethylamine (TEA; 5:2). With 0.4 mM catalyst loaded, a high turnover frequency of 1.15 × 10⁶ h^-1 was detected when under direct sunlight irradiation. In an experiment with 0.2 mM catalyst loaded, more than 140 L of H₂ (280 L of H₂ + CO₂) was produced, and a turnover number of approximately 2.78 × 10⁶ was obtained within 5 h without decline in H₂ generation activity, making it suitable for high-rate H₂ production.