Efficient CQDs/Cu2S @Ti-TPA-MOF heterojunction incorporation: A visible-light-photocatalytic composite with extended separated charges lifetime

Abstract

A sustainable strategy to tackle water pollution involves using innovative composites based on MOFs for photodecomposing antibiotic contaminants. A core-shell structure was synthesized using a solvothermal method, combining Cu₂S, carbon quantum dots (CQDs), and Ti-TPA-MOF, resulting in a material with excellent visible-light capture capabilities. Spectroscopic (XRD, XPS, BET, DRS, DLS, ESR, and PL), electrochemical (photocurrent), and microscopic (TEM) analyses were performed to characterize the photocatalyst. Adding 20 mg of Cu₂S and CQDs greatly improved gentamicin photodegradation compared to other prepared photocatalysts. This was due to enhanced electron conductivity, increased photocurrent density, a narrower energy gap, and a longer charge separation lifetime. The heterojunction composites at 150 mg/l showed a 2–6 times increase in efficiency after 90 min, surpassing the pure materials. The outcomes showed evidence of pseudo-first-order kinetics, photocatalytic activity, and excitation by visible light in the photodegradation. The stability of the photocatalytic process is evident after five cycles.