Interaction of hydrogen with model Cu-Zn methanol synthesis catalyst prepared by decomposition of mixed hydroxicarbonate is studied by inelastic neutron scattering, in situ FTIR/MS, and thermal analysis. Reduced (Cu _0.08,Zn_0.92)O mixed oxide accumulates 6H/Cu, mainly as hydride, hydroxyl and formate species. The reduction of copper in the (Cu,Zn)O mixed oxide occurs via a reversible redox interaction with H₂ and absorption of protons as OH^--groups with ν = 3250 cm^-1 and δ ≈ 1430-1480 cm^-1. Kinetic and thermodynamic parameters of this process are evaluated. The weight loss during the reduction is due to the decomposition of the residual carbonate groups to CO₂ via formate intermediates, which occurs in the presence of hydrogen. Exposure of (Cu,Zn)O to air prior to the reduction strongly affects the kinetic parameters of the reduction process.