Performance of metal catalysts to decompose aqueous phenol was experimentally investigated. Comparison of the phenol decomposition rates within three-phase fluidized-bed reactors utilizing only O-3. TiO2 deposited on silica beads, metal catalyst (Ni or Co) impregnated on mesoporous carbon beads, or O-3 in combination with each catalyst was thoroughly examined. It was found that the use of Co catalyst with the presence of O-3 led to the best removal condition which aqueous phenol was completely decomposed within 10 min (k = 0.1944 min(-1)). In contrast, the use of TiO2 without O-3 resulted in the worst decomposition of phenol (k = 0.0066 min(-1)). Some intermediate products, such as hydroquinone and catechol, were also detected but their final concentrations were negligibly low. (C) 2010 Elsevier B.V. All rights reserved.