Vanadium anchored 3D nanoconfined KIT-6 silica walls for fast oxidative desulfurization of fuel: A detailed thermodynamic and kinetic examination

Abstract

Sulfur contamination in fuel contributes to severe environmental concerns, including acid rain. Conventional desulfurization techniques are often energy-intensive, making oxidative desulfurization (ODS) a promising alternative. However, the efficiency of ODS is hindered by the poor dispersion and stability of metal active sites. In this study, we present a novel, cost-effective, and solvent-free solid-state grinding (SSG) approach for anchoring vanadium nanoparticles (Vn-NPs) into the confined spaces of as-synthesized KIT-6 (AK) for enhanced metal dispersion. Unlike conventional synthesis methodologies, the current approach ensures uniform Vn-NPs dispersion within the AK framework, reduces synthesis steps, and effectively minimizes metal aggregation. A single-step calcination simultaneously facilitates the formation of Vn-NPs within the framework and removes the P123 template. Characterization confirmed the effective Vn-NP dispersion up to 10 wt% without noticeable aggregation, while higher loadings led to particle agglomeration and structural degradation. The optimal V10AK catalyst achieved 97 % DBT conversion in 30 min using 50 mg and an O/S ratio of 4. Kinetic analysis confirmed that the ODS of DBT over V10AK follows pseudo-first-order kinetics, with an activation energy of 37.71 kJ/mol. Thermodynamic parameters (∆H = +35.27 kJ/mol, ∆S = -484.90 J/K) suggest the reaction is endothermic, non-spontaneous, yet feasible under ambient conditions. Additionally, V10AK exhibited remarkable stability and recyclability, making it a promising candidate for real-world ODS applications.