Valence Electron and Coordination Structure Guided\nMetal Active Site Design for Hydrolytic Cleavage of Carbon–Sulfide\nDouble Bonds

The\ncatalytic cleavage of carbon–sulfur (CS) double\nbonds on the metal sites without deactivation has aroused great interest\nin both fundamental catalytic research and industrial chemistry. Herein,\nactivity descriptors are developed via machine learning and density\nfunctional theory (DFT) calculations to screen transition-metal single-site\ncatalysts, which quantify the effect of both atomic electronic properties\nand coordination configuration on the hydrolysis of CS double\nbonds. The valence electron number and electronegativity of active\nsites are found to be well related to CS activation and sulfur\npoisoning, where Fe demonstrates high catalytic potential among a\nseries of metal centers. On the other hand, the isolated Fe<sub>1</sub> and Fe<sub>2</sub> sites favor carbonyl sulfide (COS) adsorption\nand activation, while the COS easily dissociates into *S and *CO on\nFe<sub>3</sub> hollow site, thus resulting in the formation of robust\nFe–S bonds and catalyst deactivation. As anticipated, the as-designed\nFe<sub>1</sub>–N<sub>4</sub> site achieves a COS conversion\nof ca. 96% at 100 °C, slightly better than the Fe<sub>2</sub>–N<sub>4</sub> site, approximately 8 times higher than that\nof the Fe/C, which is also better than those of other monatomic catalysts\n(such as Co-NC, Ni-NC, Sn-NC, and Bi-NC). The combination of in situ\ncharacterizations and theoretical calculations suggests that *COS\nand *H<sub>2</sub>O/*OH have a competitive adsorption relationship\non Fe–N<sub>4</sub> sites, and two Fe–N<sub>4</sub> sites\ncan synergistically catalyze the COS hydrolysis through the spilled\nH and OH.