Jahn–Teller Distortion in the Amino-Functionalized Metal–organic Framework Promotes CH4 Partial Oxidation with Enhanced in situ H2O2 Utilization Efficiency

The partial CH₄ oxidation by in situ generation of H₂O₂ from O₂ and H₂ offers a promising strategy to synthesize CH₃OH from affordable and sustainable substances. However, it remains a grand challenge to efficiently utilize H₂O₂ for the exclusive production of methanol. Herein, we report a tandem catalyst by encapsulating Pd nanoparticles in an amino-functionalized Fe-based metal-organic framework, delivering a CH₃OH productivity of 14.8 mmol·g_cat^-1·h^-1 with a selectivity of 98.6%. The spectroscopy characterizations suggest that the modification of the ligand by amino groups not only increases the electron density of the triiron motif through ligand-to-metal charge transfer but also induces the Jahn-Teller distortion of Fe²⁺ coordination, giving rise to the unpaired electrons at a high occupancy state, evidenced by theoretical calculations as well. Mechanism studies reveal that this unique electron configuration of Fe²⁺ facilitates H₂O₂ decomposition, resulting in an asymmetrical Fe-O octahedron with further enhanced Jahn-Teller distortion and more unpaired electrons in the σ* antibonding orbitals. This structural evolution promotes CH₄ activation with a reduced barrier of 0.35 eV for the amino-functionalized catalyst, compared to 0.47 eV for the nonfunctionalized counterpart, enabling selective formation of CH₃OH.