Design of ternary CaTiO3/g-C3N4/AgBr Z-scheme heterostructured photocatalysts and their application for dye photodegradation

Abstract

Herein we have developed a new type of ternary CaTiO3/g-C3N4/AgBr Z-scheme heterostructured photocatalysts by assembling g-C3N4 nanosheets and AgBr nanoparticles on the surface of CaTiO3 nanocuboids. The structures, micro-morphologies, chemical composition, element valence states, optical properties, surface functional groups and band-edge potentials of the derived CaTiO3/g-C3N4/AgBr photocatalysts were investigated by XRD, SEM, TEM, XPS, FTIR, UV–vis diffuse reflectance spectroscopy and electrochemical measurement. RhB was used as the model pollutant to assess the photodegradation performances of the CaTiO3/g-C3N4/AgBr photocatalysts under simulated sunlight illumination. The optimal sample is observed for CTO/10%CN/50%AgBr, which photocatalyzes 99.6% degradation of RhB after 30 min photoreaction (CRhB = 5 mg L−1, Cphotocatalyst = 0.5 g L−1). The reaction rate constants suggest that the photodegradation activity of the CTO/10%CN/50%AgBr composite is about 28.3, 19.9 and 2.0 times larger than that of bare CaTiO3, g-C3N4 and AgBr, respectively. The enhanced photodegradation performances of the ternary CaTiO3/g-C3N4/AgBr composites can be explained due to the Z-scheme electron transfer mechanism and efficient separation of photoexcited electron/hole pairs.