Theoretical insights into H2S desulfurization: Catalysis by binuclear cobalt phthalocyanine

The desulfurization process of H₂S catalyzed by binuclear cobalt phthalocyanine (bi-CoPc) has been explored theoretically. With the support of density functional theory (DFT) calculation, the desulfurization mechanism consists of active species and sulfur chain growing. Firstly, the active species has been identified, where the specific electron transfer occurs from HS⁻, traverses through the phthalocyanine ring, and culminates at O₂. This process leads to the formation of Co(I)-Co(I) complexes. Secondly, the sulfur chain growing to S₂ on bi-CoPc and detaching in the form of S₂²⁻ have been considered as the optimal path. Furthermore, a feasible and efficient bi-CoPc-based catalysts with larger π-conjugated system (naphthyl or anthracyl) has been proposed, seem to positively impact electron storage capacity and desulfurization efficiency.