Photocatalytic H2 production and transfer hydrogenation on hybrid catalyst system composed of inorganic semiconductor and molecular catalysts
Artificial photosynthetic H2 evolution and visible light driven organic synthesis have attracted much attention of scientists. Over past decades, the usually used photosensitizers were the organometallic complexes such as Ru complexes or organic compounds. However, this type of photosensitizers can only absorb a light of particular wavelength or a narrow region of light, and furthermore suffer the problem of instability or even degradation under photoirradiation condition. On the other hand, the spectral absorption range of semiconductors is usually broad and continuous, and this is potentially beneficial for the efficient collection of solar energy. Therefore, we wonder that whether we can use semiconductor to replace the traditional photosensitizer to combine with molecular catalyst for photocatalytic H2 evolution or visible light driven organic synthesis. If this strategy is feasible, the utilization ratio of light and stability for artificial photosynthetic system would be obviously enhanced.
The UV-Vis absorbance of semiconductor CdS and Ru complex photosensitizer
Herein we report an inexpensive and stable hybrid artificial photocatalytic system to mimic photosystem I (PSI) using semiconductor (CdS) as photosensitizer, cobaloximes (CoIII complexes, functional biomimetic hydrogenase) as the catalysts for H2 evolution. Under visible light irradiation (λ > 420 nm), photocatalytic H2 evolution with more than 171 turnover numbers (based on CoIII(dmgH)2pyCl 1) can be achieved, which is comparable with the highest TON obtained from homogeneous Co complexes based photocatalytic systems. The stability of this hybrid system is much superior to homogeneous system. The interfacial electron transfer from photoexcited CdS to CoIII complexes is very efficient through the weak adsorption of CoIII complexes on CdS. In fact, we found that the photocatalytic activity of CoIII(dmgH)2pyCl/CdS is even higher than that of Pt/CdS catalyst which has been considered as a highly active photocatalyst for H2 evolution. The present work demonstrates the feasibility of using semiconductors as photosensitizers and molecular complexes as H2 evolution catalysts. The combination of semiconductor with molecular catalyst may provide an alternative strategy in the design of novel stable and inexpensive artificial photosynthetic system. Corresponding research is published on J. Catal. (2011, 281, 318-324, Fuyu Wen, Jinhui Yang, Xu Zong, Baojun Ma, Donge Wang, Can Li*).
Photocatalytic H2 production on hybrid catalyst system composed of inorganic semiconductor and cobaloximes catalysts
Fuyu Wen, Jinhui Yang, Xu Zong, Baojun Ma, Donge Wang, Can Li*
J. Catal., 2011, DOI:10.1016/j.jcat.2011.05.015
A visible-light-driven transfer hydrogenation on CdS nanoparticles combined with iridium complexes
Jun Li, Jinhui Yang, Fuyu Wen, Can Li*
Chem. Commun., 2011, 47, 7080-7082
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