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Structured design of a hydrochar-supported LDH/MOF composite for improved photocatalytic applications

Abstract:

Semiconductor materials capable of absorbing visible light are of considerable importance in photocatalysis due to their energetic properties. This study presents the layered synthesis of a novel hybrid compound exhibiting enhanced photocatalytic properties. The composite led to the formation of a potential layered double hydroxide/metal–organic framework (LDH/MOF) heterojunction through the interaction of layered Mg/Al double hydroxide distributed over corn cob hydrochar (HC). Characterization techniques including XPS, XRD, SEM, and TEM corroborated this, demonstrating the presence of all three pristine materials. HC, in addition to serving as a support for nanoparticles, facilitates the distribution of LDH active sites, as evidenced by XRD, resulting in an initial composite with amorphous characteristics. XPS data indicate that Mg species derived from the LDH and dispersed over HC in the presence of the MOF ligand act as preferential binding sites during the deposition of MIL-53(Al) onto the HC/LDH surface. UV–Vis DRS results confirm that the final composite possesses a band gap (Eg) of approximately 1.55 eV, enabling activation under commercial LED light. Degradation results obtained through advanced oxidation processes (AOPs) demonstrate that pharmaceuticals (Tetracycline, Betamethasone, and Oxytetracycline) and pesticides (Metsulfuron-methyl and Nicosulfuron) achieved degradation rates exceeding 99 % within 1 h in all cases, even when the irradiation source was within the visible spectrum. Remarkably, only 20 mg of the material were required in 50 mL of solution, with each contaminant prepared at a concentration of 50 mg L-1. Consequently, we present a novel material that exhibits exceptional energy utilization efficiency for AOPs, particularly effective against emerging contaminants.