TY - JOUR
T1 - Understanding Surface Reactivity of Amorphous Transition-Metal-Incorporated Aluminum Oxide Thin Films
AU - Stoerzinger, Kelsey A.
AU - Enman, Lisa J.
AU - Cochran, Elizabeth A.
AU - Diulus, J. Trey
AU - Frederick, Ryan T.
AU - Artyushkova, Kateryna
AU - Crumlin, Ethan J.
AU - Herman, Gregory S.
AU - Boettcher, Shannon W.
N1 - Publisher Copyright:
© 2019 American Chemical Society.
PY - 2019/11/7
Y1 - 2019/11/7
N2 - The electronic structure of multimetal, amorphous oxides can be varied across a wide range of elemental compositions. Bulk properties such as conductivity, work function, and absorption can thus be tailored to suit a range of applications spanning from carrier-selective contacts to catalysis. Missing, however, is an understanding of how the surface reactivity is impacted in mixed metal-oxide amorphous films. Here we investigate the propensity of Al(1-x)M(x)Oy (M = Fe, Mn) amorphous oxide films to dissociate water into hydroxyl groups in a humid environment and find comparable hydroxylation at the low relative humidity (â0.3% RH) probed by ambient pressure X-ray photoelectron spectroscopy. In contrast, films with both Al and Fe show an increased formation of methoxy groups upon methanol exposure compared to pure Al- A nd Fe-oxide end members, indicating that the coordination environment of the amorphous oxide network impacts the acidity and redox character of surface metal and oxygen sites. These results provide guidance for the rational design of amorphous oxide layers with tailored chemical reactivity or passivity for a given application.
AB - The electronic structure of multimetal, amorphous oxides can be varied across a wide range of elemental compositions. Bulk properties such as conductivity, work function, and absorption can thus be tailored to suit a range of applications spanning from carrier-selective contacts to catalysis. Missing, however, is an understanding of how the surface reactivity is impacted in mixed metal-oxide amorphous films. Here we investigate the propensity of Al(1-x)M(x)Oy (M = Fe, Mn) amorphous oxide films to dissociate water into hydroxyl groups in a humid environment and find comparable hydroxylation at the low relative humidity (â0.3% RH) probed by ambient pressure X-ray photoelectron spectroscopy. In contrast, films with both Al and Fe show an increased formation of methoxy groups upon methanol exposure compared to pure Al- A nd Fe-oxide end members, indicating that the coordination environment of the amorphous oxide network impacts the acidity and redox character of surface metal and oxygen sites. These results provide guidance for the rational design of amorphous oxide layers with tailored chemical reactivity or passivity for a given application.
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U2 - 10.1021/acs.jpcc.9b08227
DO - 10.1021/acs.jpcc.9b08227
M3 - Article
AN - SCOPUS:85074734071
SN - 1932-7447
VL - 123
SP - 27048
EP - 27054
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
IS - 44
ER -