1. The modification of surface basicity and its role in naphthalene oxidation: The effect of the basic sites introduced by Ce.
- Author
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Jiang, Boqiong, Hua, Hao, Lin, Jianxiang, Guchen, Yijing, Han, Jingyi, and Sun, Yuhai
- Subjects
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NAPHTHALENE , *BASICITY , *NAPHTHOL , *CATALYSTS , *OXIDATION-reduction reaction , *OXIDATION - Abstract
A series of V-xCe/Ti catalysts was prepared by a step impregnation method with gradual increased Ce amount. Compared to the commercial V–W/Ti catalysts, the V-xCe/Ti catalysts exhibited considerably higher CO x selectivity during the oxidation of naphthalene (Nap), and less intermediates or by-products were detected both in gas phase and on the surface of the catalysts. Through a series of characterizations, it was found that abundance of weak basic sites in the form of OH was introduced by Ce, as well as the oxygen vacancies caused by the redox cycle of V4++Ce4+↔V5++Ce3+. The weak basic sites introduced by Ce could greatly enhance the Nap adsorption, and the Nap adsorbed was quickly converted to naphthol on Ce–OH. Furthermore, V existed at a high valence with the interaction of V and Ce, and the oxygen vacancies also increased the O ads and O OH. It improved the redox ability and the regeneration of Ce–OH on V-xCe/Ti catalysts. The intermediates could be further oxidized, and the Ce–OH consumed in the reaction could recover quickly. Therefore, almost 100% Nap conversion and a high CO x selectivity was observed in the V-xCe/Ti catalysts system. [Display omitted] • Ce introduced a lot of weak basic sites in the form of Ce–OH. • More naphthalene could adsorb and convert to naphthol on the weak basic sites. • V was kept at high valence and oxygen vacancies were produce through the interaction of Ce and V. • The intermediates during the naphthalene oxidation were further oxidized to enhance the CO x selectivity. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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