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Visible‐Light Photooxidation of Water to Oxygen at Hybrid TiO 2 –Polyheptazine Photoanodes with Photodeposited Co‐Pi (CoO x ) Cocatalyst
Author(s) -
Bledowski Michal,
Wang Lidong,
Ramakrishnan Ayyappan,
Bétard Angélique,
Khavryuchenko Oleksiy V.,
Beranek Radim
Publication year - 2012
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201200071
Subject(s) - visible spectrum , oxygen , oxygen evolution , catalysis , photochemistry , chemistry , irradiation , oxide , nanocrystalline material , water splitting , cobalt , layer (electronics) , kinetics , photocatalysis , inorganic chemistry , materials science , electrode , optoelectronics , electrochemistry , crystallography , biochemistry , physics , organic chemistry , quantum mechanics , nuclear physics
A cobalt oxide‐based oxygen‐evolving cocatalyst (Co‐Pi) is photodeposited by visible‐light irradiation onto nanocrystalline TiO 2 –polyheptazine (TiO 2 –PH) hybrid photoelectrodes in a phosphate buffer. The Co‐Pi cocatalyst couples effectively to photoholes generated in the surface polyheptazine layer of the TiO 2 –PH photoanode, as evidenced by complete photooxidation of water to oxygen under visible‐light ( λ >420 nm) irradiation at moderate bias potentials. In addition, the presence of the cocatalyst also reduces significantly the recombination of photogenerated charges, particularly at low bias potentials, which is ascribed to better photooxidation kinetics resulting in lower accumulation of holes. This suggests that further improvements of photoconversion efficiency can be achieved if more effective catalytic sites for water oxidation are introduced to the surface structure of the hybrid photoanodes.