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Stable Ta 2 O 5 Overlayers on Hematite for Enhanced Photoelectrochemical Water Splitting Efficiencies
Author(s) -
Forster Mark,
Potter Richard J.,
Yang Yi,
Li Yat,
Cowan Alexander J.
Publication year - 2018
Publication title -
chemphotochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.13
H-Index - 18
ISSN - 2367-0932
DOI - 10.1002/cptc.201700156
Subject(s) - hematite , passivation , atomic layer deposition , deposition (geology) , water splitting , materials science , chemical engineering , thin film , surface states , inorganic chemistry , layer (electronics) , chemistry , nanotechnology , catalysis , metallurgy , surface (topology) , photocatalysis , geology , paleontology , biochemistry , geometry , mathematics , sediment , engineering
Abstract Hematite (α‐Fe 2 O 3 ) is one of the most promising photoanodes for water oxidation, however the efficiencies of current hematite materials remain low. Surface trap states are often reported as one of the factors which limit the activity of hematite photoelectrodes, often leading to undesirable surface pinning and trap‐mediated recombination. The deposition of ultra‐thin Al 2 O 3 overlayers is known to enhance hematite activity through passivation of surface states, however Al 2 O 3 is rapidly degraded at normal hematite operating pH values (pH≈13). This study reports atomic layer deposition (ALD) of Ta 2 O 5 thin films as stable, passivating overlayers on a range of hematite photoelectrodes and demonstrates that enhanced activity correlates with observed changes in trap‐state dynamics.