A series of silver deposited g-C3N4 (Ag/g-C3N4) plasmonic photocatalysts with Ag loading from 0.1 to 5 wt% are prepared by thermal polymerization of urea precursor combined with the photodeposition method. The phase and chemical structure, electronic and optical properties as well as morphologies of Ag/g-C3N4 heterostructures are well-characterized. Subsequently, the photocatalytic activity of Ag/g-C3N4 is evaluated by the degradation of methyl orange (MO) and p-nitrophenol (PNP) under visible-light irradiation. The enhanced photocatalytic activity of Ag/g-C3N4 compared with g-C3N4 itself is obtained and explained in terms of the efficient visible-light utilization efficiency due to the SPR absorption of silver nanoparticles as well as fast generation, separation and transportation of the photogenerated carriers, evidenced by photoelectrochemical tests, photoluminescence measurements and free radical and hole scavenging experiments. Finally, the reusability of the catalyst is evaluated by five consecutive catalytic runs. (c) 2013 Elsevier B.V. All rights reserved.