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Imaging Anisotropic Proton Intercalation in Photochromic MoO3
Zhihang Xu1, Ting Wai Lau1, Pei Xiong1
1Department of Applied Physics, Research Institute for Smart Energy, The Hong Kong Polytechnic University, Hong Kong 00000, China.
Nano Letters
|July 26, 2024
Summary
UV light drives proton intercalation in alpha-molybdenum trioxide (α-MoO3), creating a reversible photochromic material. This process, initiated by water splitting, shows anisotropic behavior along the c-axis.
Area of Science:
- Materials Science
- Solid-State Chemistry
- Photochemistry
Background:
- Protonation is crucial for energy, environmental, and memory applications.
- Observing proton intercalation mechanisms is challenging due to proton elusiveness.
Purpose of the Study:
- To directly image proton intercalation pathways in α-MoO3.
- To understand the anisotropic behavior of proton intercalation and deintercalation.
Main Methods:
- Utilizing changes in atomic and electronic structure.
- Imaging proton intercalation pathways induced by UV illumination in α-MoO3.
Main Results:
- Revealed anisotropic proton intercalation initiated by photocatalyzed water dissociation at (001) edges.
- Demonstrated transformation of α-MoO3 to HxMoO3, realizing photochromism.
- Observed anisotropic proton deintercalation upon heating, also along the c-axis.
Conclusions:
- Anisotropic behavior is attributed to low energy barriers for proton migration along the c-axis and water dissociation/formation at (001) edges.
- The study provides insights into photochromic mechanisms in transition metal oxides.
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