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Characterization of Interfacial Charge‐Transfer Photoexcitation of Polychromium‐Oxo‐Electrodeposited TiO 2 as an Earth‐Abundant Photoanode for Water Oxidation Driven by Visible Light
Author(s) -
Chandra Debraj,
Tsuriya Ryougen,
Sato Tsubasa,
Takama Daisuke,
Abe Naoto,
Kajita Masashi,
Li Dong,
Togashi Takanari,
Kurihara Masato,
Saito Kenji,
Yui Tatsuto,
Yagi Masayuki
Publication year - 2016
Publication title -
chempluschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.801
H-Index - 61
ISSN - 2192-6506
DOI - 10.1002/cplu.201600288
Subject(s) - rutile , photocurrent , anatase , materials science , visible spectrum , photoelectrochemistry , water splitting , analytical chemistry (journal) , electrochemistry , photocatalysis , electrode , chemical engineering , chemistry , optoelectronics , biochemistry , chromatography , engineering , catalysis
Polychromium‐oxo‐deposited TiO 2 (Cr III x O y /TiO 2 ) electrodes were fabricated by a simple electrochemical technique by using different TiO 2 basal electrodes (anatase, rutile, and mixed polymorphic phases P25) as earth‐abundant photoanodes for visible‐light‐driven water oxidation. The high‐resolution transmission electron microscopy (HR‐TEM) observation illustrated that an Cr III x O y layer with approximately 2–3 nm thickness was formed on the surface of the crystalline TiO 2 particles. Upon visible‐light irradiation of the electrodes, the photoanodic current based on water oxidation was generated at the Cr III x O y /TiO 2 electrodes. However, the wavelength (below 620 nm) for photocurrent generation at Cr III x O y /TiO 2 ‐rutile was longer than that (below 560 nm) at Cr III x O y /TiO 2 ‐P25 by 60 nm, which is in agreement with the difference (0.2 eV) in the conduction band (CB) edge energy between rutile and anatase TiO 2 . This gives a quantitative account for the photocurrent generation based on interfacial charge transfer (IFCT) from Cr 3d of the deposited Cr III x O y layer to the TiO 2 CB. The photocurrent generated for Cr III x O y /TiO 2 ‐rutile was higher than that for Cr III x O y /TiO 2 ‐anatase, which is ascribed to 1) more effective Cr III x O y deposition on the rutile particles, 2) a larger electrolyte/Cr III x O y interface for water oxidation as a result of smaller rutile particles (ca. 30–40 nm) compared with larger P25 particles (ca. 40–80 nm), and 3) more effective use of visible light owing to the low energy IFCT transition of rutile.