Cu(II)-MOFs via Modulator Tuning for Tailored Cooperative Sulfur Dioxide Capture

Sulfur dioxide (SO₂) is a toxic pollutant generated from industrial emissions and the decomposition of insulating gas sulfur hexafluoride (SF₆) in electrical equipment under fault conditions, posing a serious threat to both the environment and equipment safety. Metal-organic frameworks (MOFs) have shown great potential for selective SO₂ adsorption due to their tunable pore structures and surface chemistry. However, the influence of synthesis conditions, particularly acidic modulators, on the morphology and performance of MOFs remains insufficiently explored. In this study, a copper-based MOF with accessible nitrogen sites and a three-dimensional pore system was synthesized using the nitrogen-rich ligand 5,5'-(pyrazine-2,6-diyl)diisophthalic acid (H₄L). By introducing formic acid (FA) and benzoic acid (BA) as synthesis modulators, the crystal morphology was systematically regulated and the chemical microenvironment within the pores was optimized. This strategy enabled fine control over crystal growth, resulting in a functionalized pore structure rich in nitrogen sites and adsorption active centers. Experimental results demonstrated that the optimized material, leveraging the coordinated action of modulators, achieved high SO₂ adsorption capacity and excellent selectivity, exhibiting efficient capture capability for SO₂ in SF₆ decomposition gases. This work not only provides a promising high-performance adsorbent candidate for the purification of SF₆ decomposition gases in power equipment but also offers important insights into the rational design of MOF-based materials for targeted gas capture applications by elucidating the regulatory mechanism of acidic modulators on MOF structure and performance.