A facile and low-cost route was used to synthesize a novel catalyst of alkali-activated granulated blast furnace slag-based cementitious material (ASCM) coupled with Fe2O3 by a three-step reaction of polymerization, ion exchange and impregnation. The FESEM and XRD results revealed that a high compressive strength ASCM with mean particle size about 50 nm was synthesized and Fe2O3 covered on ASCM surface in the form of clusters. The photoluminescence peak sharply decreases with increase of Fe2O3 content due to the recombination probabilities of photogenerated electron-hole pairs to be inhibited. The photocatalytic activities for degradation of Congo red (CR) dye were evaluated and the sample of ASCM loaded about 5 wt% Fe2O3 showed the highest degradation efficiency under UV irradiation. The photocatalytic degradation of CR in solution obeys second order reaction kinetics and a possible reaction mechanism is proposed. (C) 2013 Elsevier B.V. All rights reserved.