Efficient Red-Light-Driven Hydrogen Evolution with an Anthraquinone Organic Dye

Abstract

The direct utilization of the full solar spectrum to obtain renewable fuels remains a challenge because the conversion of the low-energy light (red and near-infrared) is difficult. Current light-driven systems show activity for hydrogen generation with the high-energy part of sunlight. Here we report the use of a simple anthraquinone organic dye in an artificial photosynthetic system that promotes efficient red-light-driven production of hydrogen. The system contains no noble metal and exhibits a turnover number greater than 0.78 million and a quantum yield of 30.6% at 630 nm. A mechanistic study revealed that the excited-state and redox properties of the chromophore are critical to achieving high activity and stability.

Unlocking the potential of ketocoumarins: efficient photosensitizers for sustainable light driven hydrogen evolution

“…On average, the TONs with most dyes exceeded 1000, positioning them among the best performing photosensitizers for cobaloxime catalysts. 30,31 Moreover, their straightforward synthesis using readily available and inexpensive materials, scalability, and minimal purication requirements make ketocoumarins highly attractive for practical applications in photocatalytic hydrogen production.…”

“…There are only a handful of reports utilizing organic chromophores free of either heavy atom or metal as photosensitizers for cobaloxime, 27–29 but the reported TONs in these cases often do not exceed 200. However, in a few recent reports extraordinary Turnover Numbers have been achieved in organic solvents 30 (TON 780 000) and aqueous media 31 (TON 8950), providing compelling evidence that organic chromophores in homogeneous solutions can outperform the commonly used metal complexes ( e.g. [Ru(bpy) 3 ] 2+ ) or heavy atom containing photosensitizers ( e.g.…”

Cobaloxime-based homogeneous and metal-organic framework photocatalytic systems for selective reduction of acetylene to ethylene

“…Furthermore, molecular cobaloximes are known for their long-term instability due to only hydrogen bonds holding together the equatorial ligand framework. 38,40 To stabilize the cobaloxime motifs, the following strategies can be pursued: (i) excess ligand is often added to stabilize the cobaloximes in catalytic studies; 46,47 (ii) the internal hydrogen bonding of the oximes can be replaced by difluoroborylate (BF2) groups; 39,41 and (iii) cobaloximes can be stabilized by incorporation into a MOF. 29,40 Here, we report two novel photocatalytic systems for the semihydrogenation of acetylene to ethylene: one homogeneous system using a molecular cobaloxime and one heterogeneous system based on a metal-organic framework with a cobaloxime linker (Figure 1).…”

Dynamic aggregation of carbon dots self‐stabilizes symmetry breaking for exceptional hydrogen production with near‐infrared light

“…[ 3,4 ] The solar conversion efficiency at AM1.5G will have a 10% increase for every 100 nm unit in the 600–800 nm region, thus developing broad band red‐ and NIR‐light‐responsive photosystems would be of great value for practical applications. [ 5 ] However, only a few systems can be operative under low‐energy red/NIR photon radiation to date and their performances are far from satisfactory due to severe charge recombination. [ 6–8 ]…”