Insights into the Mechanism of a Covalently Linked Organic Dye-Cobaloxime Catalyst System for Dye-Sensitized Solar Fuel Devices.
A covalently linked organic dye-cobaloxime catalyst system based on mesoporous NiO is synthesized by a facile click reaction for mechanistic studies and application in a dye-sensitized solar fuel device. The system is systematically investigated by photoelectrochemical measurements, density functional theory, time-resolved fluorescence, transient absorption spectroscopy, and photoelectron spectroscopy. The results show that irradiation of the dye-catalyst on NiO leads to ultrafast hole injection into NiO from the excited dye, followed by a fast electron transfer process to reduce the catalyst. Moreover, the dye adopts different structures with different excited state energies, and excitation energy transfer occurs between neighboring molecules on the semiconductor surface. The photoelectrochemical experiments also show hydrogen production by this system. The axial chloride ligands of the catalyst are released during photocatalysis to create the active sites for proton reduction. A working mechanism of the dye-catalyst system on the photocathode is proposed on the basis of this study.
Department of Chemistry-Ångström Laboratory, Uppsala University, Box 523, SE 751 20, Uppsala, Sweden.
Palas Baran
PB
Pati
Department of Chemistry-Ångström Laboratory, Uppsala University, Box 523, SE 751 20, Uppsala, Sweden.
Lei
L
Zhang
Department of Physics and Astronomy, Uppsala University, Box 516, SE 751 20, Uppsala, Sweden.
Bertrand
B
Philippe
Department of Chemistry-Ångström Laboratory, Uppsala University, Box 523, SE 751 20, Uppsala, Sweden.
Ricardo
0000-0002-4665-3520
R
Fernández-Terán
Department of Physics and Astronomy, Uppsala University, Box 516, SE 751 20, Uppsala, Sweden.
Sareh
S
Ahmadi
Department of Chemistry-Ångström Laboratory, Uppsala University, Box 523, SE 751 20, Uppsala, Sweden.
Lei
L
Tian
Department of Physics and Astronomy, Uppsala University, Box 516, SE 751 20, Uppsala, Sweden.
Håkan
H
Rensmo
Department of Chemistry-Ångström Laboratory, Uppsala University, Box 523, SE 751 20, Uppsala, Sweden.
Leif
L
Hammarström
Department of Chemistry-Ångström Laboratory, Uppsala University, Box 523, SE 751 20, Uppsala, Sweden.
Haining
0000-0001-6897-2808
H
Tian
D002384:Catalysis; D004396:Coloring Agents / Q000737:chemistry*; D055664:Electrochemical Techniques; D004566:Electrodes; D004583:Electrons; D004735:Energy Transfer; D009532:Nickel; D009942:Organometallic Compounds / Q000737:chemistry*; D010084:Oxidation-Reduction; D012993:Solar Energy
D004396:Coloring Agents; D009942:Organometallic Compounds; C556179:cobaloxime; D009532:Nickel; C028007:nickel monoxide
click chemistry; dye-sensitized solar cells; hydrogen; photocatalysis; reaction mechanisms