Iron-Based Metal-Organic Frameworks as Platform for H₂S Selective Conversion: Structure-Dependent Desulfurization...

Three classical Fe-MOFs, viz., MIL-100(Fe), MIL-101(Fe), and MIL-53(Fe), were synthesized to serve as platforms for the investigation of structure-activity relationship and catalytic mechanism in the selective conversion of H₂S to sulfur. The physicochemical properties of the Fe-MOFs were characterized by various techniques. It was disclosed that the desulfurization performances of Fe-MOFs with well-defined microstructures are obviously different. Among these, MIL-100(Fe) exhibits the highest catalytic performance (ca. 100% H₂S conversion and 100% S selectivity at 100-180 °C) that is superior to that of commercial Fe₂O₃. Furthermore, the results of systematic characterization and DFT calculation reveal that the difference in catalytic performance is mainly because of discrepancy in the amount of Lewis acid sites. A plausible catalytic mechanism has been proposed for H₂S selective conversion over Fe-MOFs. This work provides critical insights that are helpful for rational design of desulfurization catalysts.