Oxygen vacancy regulation strategy in V-Nb mixed oxides catalyst for enhanced aerobic oxidative desulfurization performance

• Published in: Journal of colloid and interface science 2023-07, Vol.641, p.289-298
• Main Authors: Chen, Haofeng, Liang, Chao, Xun, Suhang, Yu, Zhendong, Wu, Cancan, He, Minqiang, Li, Huaming, Zhu, Wenshuai
• Format: Article
• Language: English
• Subjects: Aerobic oxidation; catalysts; catalytic activity; density functional theory; desulfurization; DFT; energy; fuels; Oxidative desulfurization; oxygen; Oxygen vacancy; V-Nb mixed oxide
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2023.02.155

A strategy to regulate the concentration of oxygen vacancies in VNbOx by adjusting the crystal phase was proposed, which could effectively improve its catalytic activity on the oxidation of dibenzothiophene (DBT) in the oxidative desulfurization system. [Display omitted] •Different crystal phases of V-Nb mixed oxides were synthesized by one-pot method.•DFT results show that OVs generation energies are related to crystal phase.•The OVs concentration is adjusted by controlling crystal phase of V-Nb mixed oxides.•DBT, 4-MDBT and 4,6-DMDBT all can be fully oxidized under mild conditions.•The mechanism of ODS is studied by GC–MS, ESR and free radical scavenging experiments. Bimetallic oxide is a potential catalyst for oxidative desulfurization of fuel. Thus, an appropriate method is needed to improve its catalytic performance. Manufacturing defect is an effective means. In this contribution, an oxygen vacancies (OVs) regulation strategy for enhancing the catalytic activity of bimetallic oxide is proposed. Density functional theory (DFT) calculations show that the crystal phase has a huge influence on the generation energy of oxygen vacancies, so a series of V-Nb mixed oxide with different crystal phases are synthesized. Detailed characterizations show that the as-prepared tetragonal V-Nb mixed oxide (T-VNbOx) has lower OVs formation energy and larger OVs concentration (compared to orthorhombic V-Nb mixed oxides, O-VNbOx). Owing to the activation of OVs, the catalytic activity of T-VNbOx was significantly enhanced to form ultra-deep oxidative desulfurization. In addition, T-VNbOx can be cycled eight times without significantly degrading the desulfurization performance.