In-situ construction of 3D marigold-like CoAl-LDH/Ti3C2 heterosystem collaborating with 2D/2D interface for efficient photodegradation of multiple antibiotics

Developing of a photocatalyst for multiple antibiotics degradation and revealing their different mechanism are of great importance for wastewater remediation. Herein, a 3D marigold-like CoAl-LDH/Ti3C2 hybrid is developed via in situ growth of CoAl-LDH on Ti3C2 nanosheets and on-spot self-assembly during the hydrothermal process. The existence of optimized Ti3C2 steers the morphology evolution from 2D lotus leaf-like nanoplate to 3D marigold-like hierarchical architecture, which greatly boosts the adsorption capacity and photon capture of the catalyst by the increased specific surface area and the scattering cross section. Meanwhile, the well-defined 2D/ 2D interface between the components effectively promotes the electron transfer from CoAl-LDH to Ti3C2, and the photoinduced electron-hole pairs on CoAl-LDH can be greatly separated. The density functional theory (DFT) calculations further demonstrate the change of electronic structure for the composite photocatalyst. As a result, CoAl-LDH/Ti3C2 hybrid presents 85%, 56% and 70% degradation efficiency towards tetracycline hydrochloride, chloramphenicol and terramycin, which are 3.1, 3 and 2.1 times of the pristine CoAl-LDH. Furthermore, the degradation path for chloramphenicol is explored and the reason for its different degradation efficiency is revealed. The design of 3D hierarchical scaffold cooperating with 2D/2D heterogeneous interface provides a new avenue to develop ideal catalysts for wastewater remediation.