Improving benzene catalytic oxidation on Ag/Co3O4 by regulating the chemical states of Co and Ag.
J Environ Sci (China)
; 143: 201-212, 2024 Sep.
Article
in En
| MEDLINE
| ID: mdl-38644017
ABSTRACT
Silver (9 wt.%) was loaded on Co3O4-nanofiber using reduction and impregnation methods, respectively. Due to the stronger electronegativity of silver, the ratios of surface Co3+/Co2+ on Ag/Co3O4 were higher than on Co3O4, which further led to more adsorbed oxygen species as a result of the charge compensation. Moreover, the introducing of silver also obviously improved the reducibility of Co3O4. Hence the Ag/Co3O4 showed better catalytic performance than Co3O4 in benzene oxidation. Compared with the Ag/Co3O4 synthesized via impregnation method, the one prepared using reduction method (named as AgCo-R) exhibited higher contents of surface Co3+ and adsorbed oxygen species, stronger reducibility, as well as more active surface lattice oxygen species. Consequently, AgCo-R showed lowest T90 value of 183°C, admirable catalytic stability, largest normalized reaction rate of 1.36 × 10-4 mol/(h·m2) (150°C), and lowest apparent activation energy (Ea) of 63.2 kJ/mol. The analyzing of in-situ DRIFTS indicated benzene molecules were successively oxidized to phenol, o-benzoquinone, small molecular intermediates, and finally to CO2 and water on the surface of AgCo-R. At last, potential reaction pathways including five detailed steps were proposed.
Key words
Full text:
1
Database:
MEDLINE
Main subject:
Oxidation-Reduction
/
Oxides
/
Silver
/
Benzene
/
Cobalt
Language:
En
Journal:
J Environ Sci (China)
Journal subject:
SAUDE AMBIENTAL
Year:
2024
Type:
Article