Effective photocatalytic degradation of methylene blue by Cu2O/MgAl layered double hydroxides

A series of Cu2O/MgAl layered double hydroxides (Cu2O/LDHs) were first synthesized by an in situ method. X-ray diffraction analysis confirmed that Cu2O/LDH calcined at 773 K calcination temperature (Cu2O/CLDH-773) had a better crystal structure. N2-adsorption/desorption isotherms and scanning electron microscopy images indicated that the resulting Cu2O/CLDH-773 composite possesses high crystallinity, hierarchical structure as well as a large specific surface area. Energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy were used to investigate the type and content of the elements in Cu2O/CLDH-773. UV–Vis diffuse reflectance spectra confirmed that Cu2O/CLDH-773 has an absorption band whose maximum falls in the visible region. The as-prepared Cu2O/CLDH-773 displayed significant photocatalytic activity for the degradation of methylene blue (MB) under visible light irradiation. Factors that may affect the photodegradation of MB such as calcination temperature, LDHs content were studied. The stability of the photocatalysts was confirmed using reclaimed Cu2O/CLDH-773 in four successive runs, and the results indicated that Cu2O/CLDH-773 has a potential application in the field of photocatalysis. From the results of characterization and photodegradation, a possible mechanism for the photocatalytic dye degradation over Cu2O/CLDH-773 was proposed.