Aqueous-phase ketonization possesses significant advantages over gas- or organic-phase ketonization for improved conversion efficiency of aqueous fraction accompanied by algal bio-oil production. In this study, synthetized ZrO2 and Zr/Mn oxides are used for aqueous-phase ketonization of acetic acid. ZrMn0.5Ox shows the highest ketonization activity at 340 degrees C for 12 h, achieving maximum acetone yield of 88.27%; and all catalysts exhibited selectivity higher than 96.75%. Apparent activation energy and acid reaction order are 161.2 kJ mol(-1) and 0.70, respectively. Results suggest high ketonization activity of poorly crystallized tetragonal ZrO2. Addition of Mn results in ZrO2/MnOx solid solution and improves active sites. Acid property and Mn4+ content are important factors, and oxygen vacancy demonstrates relationship with ketonization activity for ZrO2. Examination of recovered catalysts indicates that ZrMnyOx exhibits improved stability, and Mn leaching and crystal phase transformation are main causes of deactivation in aqueous-phase ketonization. (c) 2017 American Institute of Chemical Engineers AIChE J, 63: 2958-2967, 2017