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.

Sulfur-Doped Graphene Oxide Quantum Dots as Photocatalysts for Hydrogen Generation in the Aqueous Phase.

Sulfur-doped graphene oxide quantum dots (S-GOQDs) were synthesized and investigated for efficient photocatalytic hydrogen generation application. The UV/Vis, FTIR, and photoluminescence spectra of the synthesized S-GOQDs exhibit three absorption bands at 333, 395, and 524 nm, characteristic of C=S and C-S stretching vibration signals at 1075 and 690 cm-1 , and two excitation-wavelength-independent emission signals with maxima at 451 and 520 nm, respectively, confirming the successful doping of S atom into the GOQDs. Electronic structural analysis suggested that the S-GOQDs exhibit conduction band minimum (CBM) and valence band maximum (VBM) levels suitable for water splitting. Under direct sunlight irradiation, an initial rate of 18 166 µmol h-1 g-1 in pure water and 30 519 µmol h-1 g-1 in 80 % ethanol aqueous solution were obtained. Therefore, metal-free and inexpensive S-GOQDs hold great potential in the development of sustainable and environmentally friendly photocatalysts for efficient hydrogen generation from water splitting.

A ruthenium-based biomimetic hydrogen cluster for efficient photocatalytic hydrogen generation from formic acid.

A ruthenium-based biomimetic hydrogen cluster, [Ru2 (CO)6 (µ-SCH2 CH2 CH2 S)] (1), has been synthesized and, in the presence of the P ligand tri(o-tolyl)phosphine, demonstrated efficient photocatalytic hydrogen generation from formic acid decomposition. Turnover frequencies (TOFs) of 5500 h(-1) and turnover numbers (TONs) over 24 700 were obtained with less than 50 ppm of the catalyst, thus representing the highest TOFs for ruthenium complexes as well as the best efficiency for photocatalytic hydrogen production from formic acid. Moreover, 1 showed high stability with no significant degradation of the photocatalyst observed after prolonged photoirradiation at 90 °C.