Hydrogen Spillover-Mediated Spatial Decoupling Process Boosts Syngas Conversion to Higher Oxygenates.

Area of Science:

• Catalysis
• Chemical Engineering
• Materials Science

Background:

• Direct conversion of syngas to higher oxygenates is challenging due to difficulties in achieving high CO conversion, oxygenate selectivity, and low C1 byproduct formation.
• Existing catalysts often struggle to balance these competing requirements, limiting their industrial applicability.

Purpose of the Study:

• To develop a multifunctional catalyst system for the direct conversion of syngas to higher oxygenates.
• To overcome the limitations of existing catalysts by precisely controlling active site arrangement and intermediate transport.
• To optimize catalyst performance for high CO conversion, oxygenate selectivity, and minimal C1 byproducts.

Main Methods:

• Development of Cu_xPd_1/SiO2|CoMn catalysts with a granule stacking architecture.
• Systematic optimization of palladium (Pd) loading, revealing a volcano-shaped relationship.
• Utilizing mechanistic studies, including spectroscopic evidence and theoretical calculations, to elucidate catalytic pathways.

Main Results:

• The optimal catalyst, Cu28Pd1/SiO2|CoMn, achieved 44.4% oxygenate selectivity (95.4% C2+OH/ROH) with low C1 products (6.4% CO2, 5.7% CH4) at 27.3% CO conversion.
• Demonstrated a volcano-shaped relationship between Pd loading and catalytic performance.
• Identified isolated Pd atom-mediated hydrogen spillover and synergistic interactions between catalyst components as key factors.

Conclusions:

• The developed multifunctional catalyst effectively addresses the challenge of direct syngas conversion to higher oxygenates.
• Precise control over spatial arrangement of active sites and intermediate transport is crucial for optimizing catalytic performance.
• A synergistic catalytic mechanism involving PdCu single-atom alloys and Co0-Co2C interfaces facilitates efficient formation of higher oxygenates.