PROBING THE CATALYTIC PERFORMANCE IN 4-NITROPHENOL REDUCTION OF TWO LANTHANIDE METAL-ORGANIC FRAMEWORKS

Tóm tắt

The discharge of 4-nitrophenol (4-NP) into natural water has prompted scientific efforts for remediation. Many effective catalysts have been proposed to reduce 4-NP using sodium borohydride, highlighting factors like robust Lewis acidity, π-conjugate systems, and water stability to enhance 4-NP decomposition. To test whether these factors are sufficient to explain the catalytic performance of materials, two metal-organic frameworks (MOFs) that fulfilled these criteria were employed to catalyze the 4-NP reduction. We synthesized two Ln-MOF-589 (Ln = Ce, La) via a reported procedure and confirmed their identity using PXRD, SEM, IR, and TGA. Contrary to expectation, their catalytic performance in reducing 4-nitrophenol with sodium borohydride exhibited low efficiency, indicating that the presence of Lewis acid or π system is insufficient to predict the catalytic activities. Still, additional factors such as metal-linker collaboration, framework-embedded metal acidity, and structural porosity should also be considered. This result underscored the need to explore lanthanide-based MOFs and carbonized Ln-MOF-589 further to unravel the catalytic mechanisms involving metal-organic frameworks, particularly in 4-NP decomposition.