Enhanced plasma-driven H2S removal from natural gas via TiO2-coated dielectric surface modification.

The efficient removal of H2S impurities from natural gas is critical for improving gas quality and reducing maintenance costs. This study explores the integration of dielectric barrier discharge (DBD) plasma with TiO2 to decompose H2S effectively. Results show that the presence of TiO2 significantly improve H2S removal and energy efficiency compared with the plasma-only condition. However, the TiO2-coated system achieves a much higher H2S removal rate (5.4 mmol/h/gTiO2), which was 27 times that of TiO2-packed system, minimizing TiO2 usage. Moreover, coated TiO2 inhibits methane conversion, preserving the primary components of natural gas. Discharge analysis reveals that packing TiO2 increases the reduced electric field and enhances mean electron energy, while coating further promotes filamentary discharge. Density functional theory (DFT) calculations confirm that defect-rich TiO2, formed under plasma conditions, plays a crucial role in facilitating H2S decomposition. A plausible reaction pathway for plasma-driven H2S decomposition with coated TiO2 is proposed. This study demonstrates the potential of DBD-coupled coated catalyst technology for efficient H2S removal, offering a scalable solution for industrial gas purification.