Vital roles of hydroxyl groups and gold oxidation states in Au/ZrO2 catalysts for 1,3-butadiene hydrogenation

► Gold oxidation states and OH-groups in Au/ZrO2 catalysts for butadiene hydrogenation. ► Reaction sensitivities to the feed moisture and density of OH-groups on ZrO2. ► Effects of gold loading and Au3+/Au0 ratio on the activity of Au/ZrO2. ► Structural features of the active sites for H2 activation.