MOF-Derived PdCo and PdMn Systems as Versatile Catalysts in Alkyne Semihydrogenation

Abstract

This study investigates the structure and catalytic properties of bimetallic nanocomposites derived from PdCo- and PdMn-based metal-organic frameworks. These materials, synthesized via chemical (Q) and thermal treatments (T), resulted in PdCo-QT and PdMn-QT catalysts containing Pd-based nanoparticles modified with Co or Mn and supported on N-doped carbon. Detailed characterization techniques confirm these complex structures, including high-resolution transmission electron microscopy, scanning transmission electron microscopy energy-dispersive X-ray spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and X-ray absorption spectroscopy. The catalytic performances of these materials were evaluated for the selective semihydrogenation of phenylacetylene and 4-octyne under soft conditions (1 H2 bar, room temperature) in batch reactors, demonstrating very high selectivity (≥95 mol %) toward alkenes at high conversion levels (≥94 mol %). Moreover, they displayed significant stability after five catalytic cycles with minimal leaching and highly competitive values of alkyne productivity in the semihydrogenation of phenylacetylene. The study also explored the potential of these catalysts in continuous gas-phase reactions, where PdCo-QT demonstrated remarkable catalytic activity and selectivity with a high gas hourly space velocity.