X-ray Insights into Formation of -O Functional Groups on MXenes: Two-Step Dehydrogenation of Adsorbed Water.
Nano Lett
; 23(4): 1401-1408, 2023 Feb 22.
Article
in En
| MEDLINE
| ID: mdl-36715492
ABSTRACT
Engineered MXene surfaces with more -O functional groups are feasible for realizing higher energy density due to their higher theoretical capacitance. However, there have been only a few explorations of this regulation mechanism. Investigating the formation source and mechanism is conducive to expanding the adjustment method from the top-down perspective. Herein, for the first time, the formation dynamics of -O functional groups on Mo2CTx are discovered as a two-step dehydrogenation of adsorbed water through in situ near-ambient-pressure X-ray photoelectron spectroscopy, further confirmed by ab initio molecular dynamics simulations. From this, the controllable substitution of -F functional groups with -O functional groups is achieved on Mo2CTx during electrochemical cycling in an aqueous electrolyte. The obtained Mo2CTx with rich -O groups exhibits a high capacitance of 163.2 F g -1 at 50 mV s -1, together with excellent stability. These results offer new insights toward engineering surface functional groups of MXenes for many specific applications.
Full text:
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Database:
MEDLINE
Language:
En
Journal:
Nano Lett
Year:
2023
Type:
Article