Theoretical Study into Water Promoted CO₂ Hydrogenation to Methanol over PdMo Alloy

Area of Science:

• Catalysis
• Surface Science
• Computational Chemistry

Background:

• Carbon dioxide (CO2) hydrogenation to methanol is a key strategy for CO2 utilization.
• Developing highly efficient catalysts for this process remains a significant challenge.

Purpose of the Study:

• To investigate the reaction mechanism and catalytic performance of methanol formation over two PdMo bimetallic surface models (st_PdMo and fl_PdMo).
• To understand how catalyst surface structure influences CO2 adsorption, activation, and subsequent hydrogenation pathways.

Main Methods:

• Density functional theory (DFT) calculations.
• Microkinetic modeling.
• Analysis of electronic structure and reaction pathways.

Main Results:

• CO2 and H2 adsorption and activation behavior are strongly dependent on the catalyst surface.
• The st_PdMo surface exhibits higher catalytic activity and methanol selectivity than the fl_PdMo surface.
• Introducing H2O to the st_PdMo system further enhances catalytic performance by lowering the kinetic barrier of the O-H formation step.

Conclusions:

• The specific surface structure of bimetallic catalysts significantly impacts CO2 hydrogenation mechanisms and efficiency.
• The st_PdMo catalyst shows promising potential for efficient methanol synthesis.
• Water co-catalysis can be a viable strategy to improve catalyst performance through enhanced electron transfer.