A facile microemulsion-assisted co-precipitation method was carried out to synthesize nano-sized Ag2CrO4 highly dispersed on the surface of porous g-C3N4 as high-efficiency visible-light-driven composite photocatalysts for the first time. The structure and morphology of the composites were systematically characterized by various techniques. Compared with Ag2CrO4 and g-C3N4, g-C3N4/Ag2CrO4 composites showed a dramatically increased photocatalytic activity in degradation of rhodamine B (RhB) and methylene blue (MB). The optimum mass ratio of the Ag2CrO4 to g-C3N4 was about 30 wM, the degradation rate of which were 6.1 (7.9) and 9.7 (15.2) times higher than pure Ag(2)Cra(4) and g-C3N4 in RhB (MB) degradation, respectively. The excellent photocatalytic activity and stability mainly benefited from the synergistic effect including smaller Ag2CrO4 particle size, high specific surface area of the composites and matched band potentials which not only promoted the separation of photon-generated charge carriers, but also inhibited the photocorrosion of Ag2CrO4. Further study revealed that the photocatalytic mechanism followed a Z-scheme which provided an efficient transfer pathway for charge carriers meanwhile endowed the composites with strong oxidation and reduction ability. Hence the porous g-C3N4/Ag2CrO4 composites are potential in environmental purification.(C) 2016 Elsevier B.V. All rights reserved.