Synergistic Control and Resource Utilization of Carbonyl Sulfur (COS) and Hydrogen Sulfide (H ₂ S) over Oxidized K-Mo Materials

Carbonyl sulfide (COS) and hydrogen sulfide (H 2 S) coexist extensively in industrial waste gases, yet conventional technologies typically address them separately, leaving synergistic control and resource utilization as ongoing challenges. This study presents a novel approach for the synergistic catalytic transformation of COS/H 2 S into high-value-added methyl mercaptan (CH 3 SH). Activity results revealed that the oxidized K-Mo/Al-O catalyst, unexpectedly active, outperforms the common sulfided K-Mo/Al-S catalyst. Characterizations suggested that K-Mo/Al-O undergoes in situ reconstruction into the K-intercalated 1T-MoS 2 phase (K x MoS 2 ), subsequently transforming into the K-decorated 2H-MoS 2 phase (K/MoS 2 ). Structure–activity relationship confirmed K x MoS 2 as the key metastable active phase for the generation of CH 3 SH, where potassium species acted as the primary active site, while Mo oxide/sulfide species played an assistant role. Temperature-programmed surface reaction of reactants (COS/H 2 /H 2 S-TPSR) and in situ diffuse reflectance infrared spectroscopy (in situ DRIFTS) elucidated that the reaction mechanism strongly depends on both reaction temperature and the active phase types, i.e., K 2 MoO 4 precursor follows an Eley–Rideal (E-R)-type direct COS hydrogenation pathway, K x MoS 2 exhibits a dual-path E-R mechanism (direct COS hydrogenation at low temperature and indirect hydrogenation at medium temperature), and K/MoS 2 primarily follows indirect COS hydrogenation at medium temperatures. This work paves a new avenue for synergistic resource utilization of multicomponent sulfur pollutants.