Methanol synthesis revisited: reaction mechanisms in CO/CO2 hydrogenation over Cu/ZnO and DFT analysis

One of the very long-standing controversies in CO/CO2 hydrogenation chemistry has been the following: What is the principal source of C in the methanol product, CO or CO2? In other words, do CO hydrogenation and CO2 hydrogenation proceed independently, in parallel, over the industrial Cu/ZnO/Al2O3 catalyst? Using state of the art experimental data and our analysis of prior studies and experimental techniques including isotopic labeling studies, including radioactive tracers, FTIR, XPS, and E-TEM, we discuss the experimental findings of the prior art and analyze the experimental and theoretical first-principles calculational data, to come up with a rational and cogent explanation for all controversial areas in methanol synthesis chemistry.