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Surface Electronic Structure Reconfiguration of Hematite Nanorods for Efficient Photoanodic Water Oxidation
Author(s) -
Fu Yanming,
Lu Ying-Rui,
Ren Feng,
Xing Zhuo,
Chen Jie,
Guo Penghui,
Pong Way-Faung,
Dong Chung-Li,
Zhao Liang,
Shen Shaohua
Publication year - 2020
Publication title -
solar rrl
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.544
H-Index - 37
ISSN - 2367-198X
DOI - 10.1002/solr.201900349
Subject(s) - overlayer , materials science , electrolyte , hematite , photocurrent , nanorod , water splitting , chemical engineering , oxide , nanoparticle , reversible hydrogen electrode , electrode , inorganic chemistry , nanotechnology , photocatalysis , optoelectronics , chemistry , metallurgy , catalysis , biochemistry , engineering , reference electrode
Hematite (α‐Fe 2 O 3 ) is a promising candidate as a semiconducting photoanode for photoelectrochemical (PEC) water splitting. However, its PEC performance is much limited by the sluggish charge transfer kinetics at the α‐Fe 2 O 3 /electrolyte interface. Herein, an insulative metal oxide, hafnium dioxide (HfO 2 ), is deposited on the surface of α‐Fe 2 O 3 to engineer the photoelectrode/electrolyte interfacial electronic structure. With the conformal HfO 2 overlayer coating, the surface defects of α‐Fe 2 O 3 are effectively passivated, whereas the charge migration from α‐Fe 2 O 3 to the electrolyte is blocked by the continuous HfO 2 overlayer, leading to a moderate PEC enhancement. In contrast, with HfO 2 nanoparticles deposited, the photogenerated holes are not only effectively extracted from the bulk of α‐Fe 2 O 3 but are also promptly injected into the electrolyte for water oxidation, due to the reconfigurated surface electronic structure. Consequently, the HfO 2 nanoparticles‐decorated α‐Fe 2 O 3 photoanode achieves an onset potential cathodic shift by 180 mV and a 460% photocurrent density enhancement, reaching up to 1.20 mA cm −2 at 1.23 V versus reversible hydrogen electrode as compared with pristine α‐Fe 2 O 3 . An alternative approach to engineer the photoelectrode/electrolyte interfacial electronic structure to improve the PEC performance for water splitting is demonstrated herein.