(268c) On the Reaction Mechanism of Methanol Synthesis and the Water Gas Shift Reaction On Cu

Methanol is industrially produced from syngas, a mixture of CO, CO₂, and H₂, over Cu/ZnO/Al₂O₃ catalysts between 230 ? 280°C and 50 ? 120 atm, but despite the prevalent use of Cu-based catalysts in industrial methanol synthesis plants several fundamental aspects of the dominating surface reactions are yet to be addressed. Using a combination of first-principles DFT calculations, microkinetic modeling, and experimental data from the literature, we derive interesting insights regarding the nature of the active site and the relative contributions of CO and CO₂ hydrogenation during methanol synthesis at various pressures, temperatures, and feed compositions. Under typical conditions CO₂ hydrogenation contributes approximately 2/3 of total methanol production. The role of the simultaneously occurring low temperature WGS reaction is also evaluated.