Synthesis of a g-C3N4-sensitized and NaNbO3-substrated II-type heterojunction with enhanced photocatalytic degradation activity

Abstract

The g-C₃N₄ (CN) sensitized and NaNbO₃ (NN) substrated II-type heterojunction (g-C₃N₄/NaNbO₃) is prepared by a solid phase calcination method with urea and NN. The layered CN is anchoring on the surface of the cubic NN. The samples are characterized by XPS, UV-vis spectroscopy, FE-SEM, XRD and FT-IR. The photodegradation mechanism of RhB solutions under visible light irradiation is investigated. Electron paramagnetic resonance (ESR) and radical scavenger experiments reveal that the main active species is O₂˙⁻ and OH˙ also plays a role in the photodegradation process. Compared with pure CN, the CN/NN hybrid materials display excellent photocatalytic activity for rhodamine b (RhB), methyl orange (MO) and tetracycline (TC) degradation under visible-light irradiation. The 8-CN/NN sample shows the highest degradation rate (1.888 h⁻¹) and it is 2.7 times higher than that of pure CN (0.697). The photodegradation of RhB, MO and TC by all the CN/NN photocatalysts fits to pseudo first order kinetics. The photocatalysts also possess great stability. The exploration of the CN/NN photocatalyst is significant for the further practical application of photocatalysis in wastewater treatment.