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Hematite Photoanode with Complex Nanoarchitecture Providing Tunable Gradient Doping and Low Onset Potential for Photoelectrochemical Water Splitting
Author(s) -
Ahn HyoJin,
Goswami Anandarup,
Riboni Francesca,
Kment Stepan,
Naldoni Alberto,
Mohajernia Shiva,
Zboril Radek,
Schmuki Patrik
Publication year - 2018
Publication title -
chemsuschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.412
H-Index - 157
eISSN - 1864-564X
pISSN - 1864-5631
DOI - 10.1002/cssc.201800256
Subject(s) - hematite , photocurrent , water splitting , nanorod , materials science , oxygen evolution , doping , hydroxide , nanotechnology , reversible hydrogen electrode , chemical engineering , anode , photoelectrochemistry , electrode , inorganic chemistry , electrochemistry , chemistry , catalysis , photocatalysis , optoelectronics , metallurgy , working electrode , biochemistry , engineering
Over the past years, α‐Fe 2 O 3 (hematite) has re‐emerged as a promising photoanode material in photoelectrochemical (PEC) water splitting. In spite of considerable success in obtaining relatively high solar conversion efficiency, the main drawbacks hindering practical application of hematite are its intrinsically hampered charge transport and sluggish oxygen evolution reaction (OER) kinetics on the photoelectrode surface. In the present work, we report a strategy that synergistically addresses both of these critical limitations. Our approach is based on three key features that are applied simultaneously: i) a careful nanostructuring of the hematite photoanode in the form of nanorods, ii) doping of hematite by Sn 4+ ions using a controlled gradient, and iii) surface decoration of hematite by a new class of layered double hydroxide (LDH) OER co‐catalysts based on Zn–Co LDH. All three interconnected forms of functionalization result in an extraordinary cathodic shift of the photocurrent onset potential by more than 300 mV and a PEC performance that reaches a photocurrent density of 2.00 mA cm −2 at 1.50 V vs. the reversible hydrogen electrode.