Micro-Structure Engineering in Pd-InO_x Catalysts and Mechanism Studies for CO₂ Hydrogenation to Methanol

Area of Science:

• Catalysis
• Materials Science
• Chemical Engineering

Background:

• Palladium-Indium Oxide (Pd-InOx) catalysts show promise for CO2 hydrogenation to methanol.
• Controlling active sites and understanding reaction mechanisms are critical challenges.

Purpose of the Study:

• To synthesize and characterize Pd-InOx catalysts with controlled active sites.
• To investigate the influence of different active sites on CO2 hydrogenation performance and reaction pathways.

Main Methods:

• Synthesis of Pd-InOx catalysts with varying Palladium loadings.
• Characterization of active sites (In-O, Pd-O(H)-In, Pd2In3).
• In situ DRIFTS studies to analyze reaction intermediates and pathways.

Main Results:

• Identified three distinct active sites: In-O, Pd-O(H)-In, and Pd2In3.
• Pd-O(H)-In sites enhanced low-temperature activity; Pd2In3 sites improved high-temperature performance.
• Shift in reaction intermediates (*HCOO to *COOH) observed with different active sites, altering product distribution.

Conclusions:

• Active site engineering in Pd-InOx catalysts is crucial for optimizing CO2 hydrogenation.
• Understanding the relationship between active sites, intermediates, and performance guides rational catalyst design for CO2 conversion.