ZnO was tested as possible methanol and - since formaldehyde is one of the key intermediates in methanol conversion reactions - also as formaldehyde steam reforming catalyst. Catalytic experiments in a batch as well as a flow reactor resulted in highly selective steam reforming, though at low specific activities, of formaldehyde and methanol over ZnO toward CO2 (selectivity of 95-99.6%). Comparison of the behavior of ZnPd near-surface intermetallic phases, unsupported intermetallic ZnPd and supported ZnPd/ZnO catalysts reveals that formaldehyde is formed from methanol in parallel with CO2 on the former, while on unsupported intermetallic ZnPd and ZnO-supported ZnPd, it is efficiently reacted toward CO2, thus, a beneficial role of ZnO in oxidizing formaldehyde-derived intermediates toward CO2 is evident. (c) 2012 Elsevier Inc. All rights reserved.