Infrared spectroscopy has been used to study the possible adsorption and decomposition of CO2 on a copper containing methanol catalyst. It is demonstrated that the spectra from in situ infrared studies of the methanol synthesis can be complicated by many CO2 combination bands in the 2200-1900 cm(-1) region. A comparison with previously published DRIFTS spectra from studies of copper catalysts exposed to CO2 shows that nearly all of the bands assigned as CO adsorbed on copper originate from gas phase CO2.