Electron transfer mediated by iron carbonyl clusters enhance light-driven hydrogen evolution in water by quantum dots

In the present study, assemblies consisting of CdSe quantum dots that are coupled with one of two molecular complexes/catalysts, viz . [Fe 2 S 2 (CO) 6 ] or [Fe 3 Te 2 (CO) 9 ], using an interface‐directed approach, have been tested as catalytic systems for hydrogen production in aqueous solution/organic solution.

In the presence of ascorbic acid as a sacrificial electron donor and proton source, these assemblies exhibit enhanced activities for the rate of hydrogen production under visible light irradiation for 8 hrs in aqueous solution at pH 4.0 with up to 110 μmol of H 2 per mg of assembly, almost 8.5 times that of pure CdSe quantum dots under the same conditions.

Transient absorption and time‐resolved photoluminescence spectroscopies have been used to investigate the charge carrier transfer dynamics in the quantum dot/iron carbonyl cluster assemblies. The spectroscopic results indicate that effective electron transfer from the molecular iron complex to the valence band of the excited CdSe quantum dots to the significantly inhibits the recombination of photogenerated charge carriers, boosting the photocatalytic activity for hydrogen generation; i.e . the iron clusters function as effective intermediaries for electron transfer from the sacrificial electron donor to the valence band of the quantum dots.