title: Surface engineered doping of hematite nanorod arrays for improved photoelectrochemical water splitting.
abstract: Given the narrow band gap enabling excellent optical absorption, increased charge carrier density and accelerated surface oxidation reaction kinetics become the key points for improved photoelectrochemical performances for water splitting over hematite (α-Fe2O3) photoanodes. In this study, a facile and inexpensive method was demonstrated to develop core/shell structured α-Fe2O3 nanorod arrays. A thin, Ag-doped overlayer of ~2-3 nm thickness was formed along α-Fe2O3 nanorods via ultrasonication treatment of solution-based β-FeOOH nanorods in Ag precursor solution followed by high temperature annealing. The obtained α-Fe2O3/AgxFe2-xO3 core/shell nanorod films demonstrated much higher photoelectrochemical performances as photoanodes than the pristine α-Fe2O3 nanorod film, especially in the visible light region; the incident photon-to-current efficiency (IPCE) at 400 nm was increased from 2.2% to 8.4% at 1.23 V vs. RHE (Reversible hydrogen electrode). Mott-Schottky analysis and X-ray absorption spectra revealed that the Ag-doped overlayer not only increased the carrier density in the near-surface region but also accelerated the surface oxidation reaction kinetics, synergistically contributing to the improved photoelectrochemical performances. These findings provide guidance for the design and optimization of nanostructured photoelectrodes for efficient solar water splitting.
authors.affiliation: 1] International Research Center for Renewable Energy, State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, Shaanxi 710049, China [2] Department of Mechanical Engineering, University of California at Berkeley, Berkeley, CA 94720, United States.
authors.forename: Shaohua
authors.initials: S
authors.lastname: Shen
authors.affiliation: Canadian Light Sources Inc., 44 Innovation Boulevard, Saskatoon, S7N2V3, Canada.
authors.forename: Jigang
authors.initials: J
authors.lastname: Zhou
authors.affiliation: National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu Science Park, Hsinchu 30076, Taiwan, China.
authors.forename: Chung-Li
authors.initials: CL
authors.lastname: Dong
authors.affiliation: Canadian Light Sources Inc., 44 Innovation Boulevard, Saskatoon, S7N2V3, Canada.
authors.forename: Yongfeng
authors.initials: Y
authors.lastname: Hu
authors.affiliation: National Synchrotron Radiation Research Center, 101 Hsin-Ann Road, Hsinchu Science Park, Hsinchu 30076, Taiwan, China.
authors.forename: Eric Nestor
authors.initials: EN
authors.lastname: Tseng
authors.affiliation: International Research Center for Renewable Energy, State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, Shaanxi 710049, China.
authors.forename: Penghui
authors.initials: P
authors.lastname: Guo
authors.affiliation: International Research Center for Renewable Energy, State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, Shaanxi 710049, China.
authors.forename: Liejin
authors.initials: L
authors.lastname: Guo
authors.affiliation: Department of Mechanical Engineering, University of California at Berkeley, Berkeley, CA 94720, United States.
authors.forename: Samuel S
authors.initials: SS
authors.lastname: Mao