Efficient hydrolytic desulfurization of carbon disulfide using palladium-anchored bipyridine and phenanthroline-based organic polymers under mild conditions

Abstract

The design and development of innovative catalysts have emerged as a significant research focus in the field of catalytic hydrolysis of sulfur-containing small molecules. In this study, two nitrogen-rich microporous polymer catalysts with anchored palladium (II) active sites were synthesized through a post-coordination modification technique applied to a two-dimensional organic porous polymer matrix. The amorphous morphology of these porous catalysts offers a wide range of pore sizes and adsorption capacity, facilitating the efficient adsorption of carbon disulfide (CS₂) molecules and subsequent catalytic desulfurization within confined spaces. The hydrolytic desulfurization efficiency of two Pd-containing organic polymer porous catalysts reached up to 12.69 μmol/g/h, which represents a 4.1-fold increase compared to the efficiency of small molecule complex catalysts with the same palladium content reported in earlier studies under the homogeneous condition. Through the incorporation of concentrated nitric acid (HNO₃) as a sacrificial agent, the efficiency of catalytic desulfurization increased by a factor of 23.2. Additionally, the catalyst was activated and reused multiple times. Density functional theory (DFT) calculation results have validated the mechanism and reaction pathway involved in the cleavage of C=S bond induced by the nucleophilic attack of hydroxide (OH^–) ions. These results offer novel perspectives and methods for the design and fabrication of heterogeneous supported metal–organic porous polymer catalysts.