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The Orientation Dependence of the Photochemical Activity of α‐Fe 2 O 3
Author(s) -
Zhu Yisi,
Schultz Andrew M.,
Rohrer Gregory S.,
Salvador Paul A.
Publication year - 2016
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.14201
Subject(s) - crystallite , orientation (vector space) , hematite , plane (geometry) , kelvin probe force microscope , aqueous solution , materials science , chemistry , crystallography , atomic force microscopy , mineralogy , nanotechnology , geometry , mathematics
The orientation dependence of the visible‐light stimulated photochemical reduction of aqueous Ag + on polycrystalline hematite Fe 2 O 3 was determined by observing the relative amount of reduced Ag 0 on crystals of known surface orientation over all possible orientations. The results show that surfaces oriented within 20° of the ( 1 1 ¯ 02 ) plane are the most active and surfaces close to the (0001) plane are the least active. A strong correlation is observed between the orientation‐dependent activity and the orientation‐dependent surface potential measured by scanning Kelvin probe force microscopy. Surfaces near the most active ( 1 1 ¯ 02 ) plane and the least active (0001) plane are, respectively, at the most positive and the least positive ends of the potential range among all grains. The trends in activity are concluded to arise from a combination of internal fields associated with surface charges and bulk transport effects.