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Nb‐Doped Hematite Nanorods for Efficient Solar Water Splitting: Electronic Structure Evolution versus Morphology Alteration
Author(s) -
Fu Yanming,
Dong ChungLi,
Lee WanYi,
Chen Jie,
Guo Penghui,
Zhao Liang,
Shen Shaohua
Publication year - 2016
Publication title -
chemnanomat
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.947
H-Index - 32
ISSN - 2199-692X
DOI - 10.1002/cnma.201600024
Subject(s) - nanorod , photocurrent , dopant , materials science , doping , hematite , water splitting , aqueous solution , energy conversion efficiency , morphology (biology) , charge carrier , nanotechnology , chemical engineering , optoelectronics , photocatalysis , chemistry , metallurgy , biochemistry , engineering , catalysis , biology , genetics
In this study, Nb‐doped α‐Fe 2 O 3 nanorod photoanodes were prepared via a facile solution‐based process by directly adding NbCl 5 in the aqueous solution. The morphology and electronic structure of Nb‐doped α‐Fe 2 O 3 films depended strongly on the dopant concentrations. Compared with the undoped sample, the optimal Nb‐doped α‐Fe 2 O 3 film showed an approximately 4‐fold photocurrent increase under solar light at 1.0 V versus Ag/AgCl, and the incident photon‐to‐current conversion efficiency was increased by 2.5 times, reaching 13.7 % at 350 nm and 1.23 V versus RHE. The enhancement in PEC activity, as induced by moderate Nb doping, was attributed to the increased charge carrier density for promoted charge transfer ability as well as the smaller nanorod diameter for shortened charge transfer distance. However, superfluous Nb dopants would destroy the nanorod structure and greatly reduce the thickness of α‐Fe 2 O 3 films, leading to poor optical absorption and thus decreased photoelectrochemical performance.