Dynamic Interconversion of Ga(III) and GaH_x in Ga-MFI Zeolites for Efficient CO₂-Cyclohexane Coupling Conversion to...

The catalytic coupling conversion of naphtha and CO₂ to aromatics over metal-zeolites offers a fascinating route for aromatics production, yet, the exploitation of efficient metal-zeolite catalysts and CO₂ coupled naphtha to make CO₂ transformed into high-value-added chemicals remain great challenges. Herein, we synthesized a framework-anchored Ga-MFI catalyst synthesized via ligand-assisted hydrothermal crystallization, achieving 80.76% aromatic selectivity at 99.57% cyclohexane conversion (550 °C, 0.1 MPa, WHSV = 1 h^-1) with over 110 h stability for CO₂ and cyclohexane (as a model naphthenic compound) coupling reaction. Multimodal in situ characterization (XAFS, synchrotron XRD, and FTIR) reveals that isolated Ga(III) species undergo reversible coordination switching to GaH_x under reaction conditions, dynamically mediating CO₂ activation through Ga species transfer. Tetrahedrally coordinated Ga-O sites synergize with proximal Brønsted acid sites. Isotopic tracing (¹³CO₂) demonstrates 56.4% of aromatic carbon originates. The catalyst's self-recovery capability ensures structural integrity and suppresses deactivation. This work establishes a dynamic single-site catalysis framework for a CO₂ coupled alkane, advancing the design of zeolite-confined metal catalysts through precise microenvironment engineering.