Atomic scale g-C3N4/Bi2WO6 2D/2D heterojunction with enhanced photocatalytic degradation of ibuprofen under visible light irradiation

•A novel atomic scale g-C3N4/Bi2WO6 heterojunction (UTCB) was synthesized by a simple and efficient way.•Effective charge transfer across substantial heterojunction interface.•The large specific area of the ultrathin heterojunction providing more active sites.•Higher photocatalytic efficiency toward ibuprofen.•Four photodegradation pathways of ibuprofen under visible light irradiation were proposed.

Although photocatalytic degradation is an ideal strategy for cleaning environmental pollution, it remains challenging to construct a highly efficient photocatalytic system by steering the charge flow in a precise manner. In this study, a novel atomic scale g-C3N4/Bi2WO6 heterojunction (UTCB) constructed by ultrathin g-C3N4 nanosheets (ug-CN) and monolayer Bi2WO6 nanosheets (m-BWO) was successfully prepared by hydrothermal reaction. The UTCB heterojunctions were characterized by various techniques including XRD, TEM, AFM, BET measurements, UV-vis spectrometry, and XPS. The results indicated that UTCB heterojunctions were assembly of m-BWO on ug-CN and presented high separation efficiency of photogenerated carriers. Under visible light irradiation, the optimum molar ratio of ug-CN/m-BWO (1:4, UTCB-25) reached almost 96.1% removal efficiency of IBF within 1 h, which was about 2.7 times as that of pure m-BWO. The photocatalytic mechanisms of UTCB-25 were revealed, suggesting that the synergistic effect of UTCB-25 heterojunction with strong interfacial interaction promoted the photoinduced charge separation. According to the LC-MS/MS, five photodegradation pathways of IBF under visible light irradiation were proposed. This study could open new opportunities for the rational design and a better understanding of atomic scale two dimensions/two dimensions (2D/2D) heterojunctions in environmental or other applications.

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