In this paper, a photoelectrocatalytic (PEC) system consisting of gamma-Bi2MoO6 anode and Co3O4 loaded carbon fiber paper (Co3O4/CFP) cathode prepared by a hydrothermal method was established and used to degrade phenol. In order to enhance the PEC degradation efficiency of phenol, peroxymonosulfate (PMS) was introduced into this system. At an applied bias of 1.5 V, the removal efficiency of 10 mg/L phenol was increased from 6% to 100% with 2 mM PMS addition into the PEC process. The degradation rate constant of phenol was also increased to be 0.0496 min(-1). Effects of PMS concentration, applied bias and initial pH were investigated. Based on the ESR analysis, sulfate radicals (SO4.-) and hydroxyl radicals (Ho.) were proved to be the dominant oxidizing species for phenol degradation in the combined system. The PMS was activated to generate SO4.- by loaded Co3O4, in which photogenerated-electrons accelerated the cobalt cycle process on the cathode. As a result, Co leaching was largely inhibited. The stability of the PEC system for organics degradation was exhibited. (C) 2017 Elsevier Inc. All rights reserved.