MXene Ti3C2 derived Z–scheme photocatalyst of graphene layers anchored TiO2/g–C3N4 for visible light photocatalytic degradation of refractory organic pollutants

Highly photoactive Z–scheme of graphene layers anchored TiO2/g–C3N4 (GTOCN) photocatalyst was synthesized from MXene Ti3C2 through one–step in–situ calcination, and used for tetracycline (TC) and ciprofloxacin (CIP), bisphenol A (BPA) and rhodamine B (RhB) degradation under visible light irradiation. The crystal phases, chemical compositions, morphological structures and photoelectrochemical properties were characterized. The results demonstrated that hierarchical structured GTOCN photocatalysts exhibited significant improvement in visible light adsorption and photogenerated carriers separation. The GTOCN3 presented the best visible light photocatalytic synergism of degradation rate towards TC (0.02442 min−1), CIP (0.01675 min−1), BPA (0.01935 min−1) and RhB (0.05586 min−1), which was much higher than that of graphene layers anchored TiO2, g–C3N4 and g–C3N4/TiO2(P25), benefitting from solid interactions among graphene, TiO2 and g–C3N4 for separation and accumulation of g–C3N4 electrons with high reduction capability and TiO2 holes with high oxidation capability. Furthermore, the main species of O2− and OH for pollutants decomposition was confirmed by free radical capture and electron spin resonance experiments. Besides, the acceptable reusability and stability indicated the great application potential of GTOCN in pharmaceuticals, endocrine disruptors and colourants contained wastewater disposal and environmental protection.