Construction of S-scheme heterojunction via incorporating g-C3N4 into Ce-based MOFs for promotion of charge-transfer in photocatalytic Cr(VI) detoxification

According to several theories on the properties of Ce-based metal-organic frameworks (MOFs), they are famed for their efficient light utilization in addition to great charge separation. The conjugation of this group of MOFs with graphitic carbon nitride (g-C3N4), as a metal-free visible light-activated photocatalyst, evolves a consistent structure that possesses the specifications of both MOF and semiconductor. The main objective of this study was the integration of four MOFs based on cerium with g-C3N4 through facile methods. Fortunately, the mentioned objective claimed by successfully synthesizing g-C3N4/Ce-UiO-66, g-C3N4/Ce-MOF-808, g-C3N4/Ce-BDC-NH2, g-C3N4/Ce-BDC and several characterization techniques such as XRD, IR, UV–vis DRS, SEM, EIS, and Mott–Schottky were employed to confirm completion synthesis. This study also provides new insights into the global concern for the excessive entrance of Cr(VI), a highly toxic heavy metal, into wastewater. To remove this ion, g-C3N4/Ce-BDC was chosen owing to its appealing photocatalytic features. The result of 98.5% toward photocatalytic Cr(VI) reduction in an aqueous system was attained within 90 min. Moreover, under acidic conditions, the catalyst kept its stability after four runs of reaction.