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.