Co/CuZnO is known as a base metal catalyst active for C2+ oxygenate synthesis. This study probed the interactions of the different components of Co/CuZnO catalysts on CO hydrogenation using Fischer-Tropsch synthesis (250 degrees C, H-2/CO = 2) and SSITKA. Only combination of all three metal components produced a catalyst with relatively high C2+ oxygenate selectivity, but with much lower activity compared to that for Co/Al2O3. In situ reaction characterizations, albeit at somewhat different conditions than alcohol synthesis, helped explain interaction of the components. SSITKA, under methanation conditions, indicated that the most striking feature for the combination of Co with ZnO and/or Cu was a much decreased amount of reaction intermediates. Ethane hydrogenolysis results suggested that the different components for these catalysts were in close contact and few or no large ensembles (n >= 12) of Co atoms existed, confirming that ZnO and/or Cu covered/blocked a substantial number of active sites on Co for CO hydrogenation. (C) 2011 Elsevier Inc. All rights reserved.