Creation of Heterogeneous Single-Site Catalysts for RWGS Reaction: Ruthenium Complex on Porous Ionic Polymers via...

Area of Science:

• Materials Science
• Catalysis
• Nanotechnology

Background:

• Heterogeneous single-metal-site catalysts (HSMSCs) offer advantages like uniform active sites, easy separation, and recyclability.
• Developing practical synthesis strategies for HSMSCs is crucial for their widespread application.

Purpose of the Study:

• To synthesize a novel heterogeneous single-site ruthenium catalyst (Ru/PIPs-IL3) on porous ionic polymers.
• To investigate the anchoring mechanism of ruthenium onto the polymer support via electrostatic interactions.
• To evaluate the catalytic performance of Ru/PIPs-IL3 in the low-temperature reverse water-gas shift reaction.

Main Methods:

• Synthesis of Ru/PIPs-IL3 via electrostatic interactions between quaternary phosphonium cations and cyclopentadienyl ligand anions.
• Characterization using X-ray photoelectron spectroscopy (XPS), attenuated total reflection infrared spectroscopy (ATR-IR), high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), and extended X-ray absorption fine structure (EXAFS).
• Density functional theory (DFT) calculations and X-ray crystallography to confirm strong electrostatic interactions.

Main Results:

• Ru/PIPs-IL3 was successfully synthesized, with ruthenium anchored via strong electrostatic interactions (ΔH = -73.4 to -83.5 kJ/mol).
• The catalyst exhibited twofold higher activity compared to homogeneous counterparts.
• Achieved a turnover number (TON) of up to 545 and 98.5% CO selectivity in the reverse water-gas shift reaction.

Conclusions:

• Porous ionic polymers (PIPs-IL3) effectively anchor Shvo's catalyst through electrostatic interactions, creating a stable heterogeneous single-site ruthenium catalyst.
• The Ru/PIPs-IL3 catalyst demonstrates superior performance in the low-temperature reverse water-gas shift reaction, highlighting its potential for industrial applications.