Perovskite oxide ultrathin nanosheets/g-C3N4 2D-2D heterojunction photocatalysts with significantly enhanced photocatalytic activity towards the photodegradation of tetracycline

•2D-2D g-C3N4/K+Ca2Nb3O10− nanosheet heterojunctions were fabricated.•The g-C3N4/K+Ca2Nb3O10− heterojunctions have strong interfacial interaction.•The nanosheet heterojunctions showed enhanced visible light photocatalytic activity.•The enhanced activity was mainly due to the synergistic effect of heterojunctions.•The superoxide radicals and holes are the two main photoactive species.

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.

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