In situ formation of Cu2O decorated CuZnAl-layered double hydroxide heterostructured photocatalysts for enhancing the degradation of tetracycline under visible light

Abstract

Elimination of antibiotics such as tetracycline hydrochloride (TC) from wastewater is of great significance, but still faces challenges. In this regard, Cu₂O decorated CuZnAl-layered double hydroxide (Cu₂O/CuZnAl-LDHs) heterostructure photocatalysts were designed via a facile coprecipitation method and subsequent in situ reduction approach. The XRD, XPS, UV-vis DRS, PL, Mott–Schottky plots, and VB-XPS results together revealed that the construction of a heterostructure inhibits the recombination of relatively useful electrons and holes, providing a strong driving force for the photocatalytic degradation of TC. Additionally, the synergistic effects increased visible light absorption and the population of adsorption sites, which also played pivotal roles in the removal of TC. As a result, the degradation efficiency of TC catalyzed by Cu₂O/CuZnAl-LDHs under visible light reached 94.1% within 120 min. The capture experiments of active species and ESR analysis confirm that the superoxide radical (˙O₂⁻), holes (h⁺) and hydroxyl radicals (˙OH) were responsible for the decomposition of TC. This study provides a rational design strategy and performance assessment of LDH-based heterostructured photocatalysts for the treatment of antibiotic-contaminated water.