A critical review towards the causes of the iron-based catalysts deactivation mechanisms in the selective oxidation of hydrogen sulfide to elemental sulfur from biogas

Hydrogen sulfide (H2S) not only presents significant environmental concerns but also induces severe corrosion in industrial equipment, even at low concentrations. Among various technologies, the selective oxidation of hydrogen sulfide (SOH2S) to elemental sulfur (S) has emerged as a sustainable and environmentally friendly solution. Due to its unique properties, iron oxide has been extensively investigated as a catalyst for SOH2S; however, rapid deactivation has remained a significant drawback. The causes of iron oxide-based catalysts deactivation mechanisms in SOH2S, including sulfur or sulfate deposition, the transformation of iron species, sintering and excessive oxygen vacancy formation, and active site loss, are thoroughly examined in this review. By focusing on the deactivation mechanisms, this review aims to provide valuable insights into enhancing the stability and efficiency of iron-based catalysts for SOH2S.