Novel visible-light-driven 2D-2D heterojunction photocatalysts was constructed, based on 2D g-C3N4 and exfoliated ultrathin K+Ca2Nb3O10- nanosheets, which is derived from Dion-Jacobson phase layer perovskites. The photocatalytic performance of the 2D-2D g-C3N4/K+Ca2Nb3O10- nanosheet heterojunctions was evaluated by the degradation of tetracycline hydrochloride under visible light irradiation. Compared with bare K+Ca2Nb3O10- and g-C3N4, the g-C3N4/K+Ca2Nb3O10- nanosheet heterojunctions exhibited considerably enhanced photocatalytic activity towards the degradation of tetracycline hydrochloride, which is about 6.6 and 1.8 times higher than that of pure K+Ca2Nb3O10- and g-C3N4, respectively. This enhanced activity can be mainly attributed to the synergistic effect of g-C3N4/K+Ca2Nb3O10-nanosheet heterojunctions with strong interfacial interaction and abundant 2D coupling interfaces, which could efficiently promote the photo-induced charge separation. The results of work demonstrated that construction of 2D-2D heterojunctions is an effective strategy to obtain the enhanced photocatalytic activity towards the degradation of tetracycline hydrochloride. (C) 2016 Published by Elsevier B.V.