Direct selective oxidation of H2S to elemental sulfur using Ni, Co, V and W doped TiO2 nanorods

Hydrogen sulfide (H₂S) is a highly toxic gas commonly encountered in petroleum refining and natural gas processing. Its selective oxidation to elemental sulfur is a promising approach for mitigating environmental and operational hazards, but achieving high selectivity under mild conditions remains challenging. In this study, TiO₂ nanorods doped with transition metals (Ni, Co, V, W) were synthesized via a hydrothermal-calcination route and evaluated for direct H₂S oxidation at 190 °C. Comprehensive characterization using X-ray diffraction (XRD), transmission electron microscopy (TEM), field-emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller analysis (BET), and energy-dispersive X-ray spectroscopy (EDS) confirmed the successful incorporation of metal dopants. The 6 wt% V/TiO₂ catalyst exhibited the best performance, achieving > 97.3% H₂S conversion and > 97.1% elemental sulfur selectivity over 14 h of continuous operation. This work introduces a robust nanocatalyst platform for low-temperature sulfur recovery and establishes an optimal dopant loading strategy to balance performance, cost, and stability. The novelty of this work lies in establishing a correlation between mesostructural evolution and catalytic efficiency, demonstrating the potential of doped TiO₂ nanorods for scalable environmental applications.