Insights into the intrinsic kinetics for efficient hydrodesulfurization of 4,6-dimethyldibenzothiophene over mesoporous CoMoS2/ZSM-5

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

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.

Single Mo Atoms Stabilized on High-Entropy Perovskite Oxide: A Frontier for Aerobic Oxidative Desulfurization

The design and preparation of catalysts with both excellent stability and maximum exposure of catalytic active sites is highly desirable; however, it remains challenging in heterogeneous catalysis. Herein, a entropy-stabilized single-site Mo catalyst via a high-entropy perovskite oxide LaMn_0.2Fe_0.2Co_0.2Ni_0.2Cu_0.2O₃ (HEPO) with abundant mesoporous structures was initiated by a sacrificial-template strategy. The presence of electrostatic interaction between graphene oxide and metal precursors effectively inhibits the agglomeration of precursor nanoparticles in a high-temperature calcination process, thereby endowing the atomically dispersed Mo⁶⁺ coordinated with four O atoms on the defective sites of HEPO. The unique structure of single-site Mo atoms' random distribution with an atomic scale greatly enriches the oxygen vacancy and increases surface exposure of the catalytic active sites on the Mo/HEPO-SAC catalyst. As a result, the obtained Mo/HEPO-SAC exhibits robust recycling stability and ultra-high oxidation activity (turnover frequency = 3.28 × 10^-2) for the catalytic removal of dibenzothiophene (DBT) with air as the oxidant, which represents the top level and is strikingly higher than the state-of-the-art oxidation desulfurization catalysts reported previously under the same or similar reaction conditions. Therefore, the finding here for the first time expands the application of single-atom Mo-supported HEPO materials into the field of ultra-deep oxidative desulfurization.