BaTiO3/CeO2 heterojunction photocatalysts: design, construction and a novel application for the photocatalytic degradation of oxytetracycline hydrochloride

Abstract A polyacrylamide gel method combined with low temperature calcination technology has been developed to synthesize the BaTiO 3 /CeO 2 heterojunction photocatalysts, which were formed by hybriding the large BaTiO 3 particles and fine CeO 2 nanoparticles with varied mass percent of CeO 2 . Various characterization methods have been used to determine the phase structure, functional group information, elemental composition, microstructure, optical and photocatalytic activity of BaTiO 3 /CeO 2 heterojunction photocatalysts. The introduction of CeO 2 into the host lattice of BaTiO 3 does not change the optical band gap value (Eg = 3.20 eV) of the host lattice. As expected, the BaTiO 3 /CeO 2 heterojunction photocatalysts exhibit highly enhanced and CeO 2 composition-dependent photocatalytic activity for the degradation of oxytetracycline hydrochloride under simulated sunlight irradiation. The BaTiO 3 /5 wt% CeO 2 , BaTiO 3 /10 wt% CeO 2 , and BaTiO 3 /15 wt% CeO 2 showed lower photocatalytic activity, while BaTiO 3 /20 wt% CeO 2 showed highest photocatalytic activity (96.89 %) over the single component BaTiO 3 and CeO 2 photocatalysts with the initial oxytetracycline hydrochloride concentration, photocatalyst content and irradiation time were 100 mg/L, 1.5 g/L and 120 min, respectively. The enhanced photocatalytic activity of BaTiO 3 /20 wt% CeO 2 heterojunction photocatalysts is ascribed to the cooperation between Ce 3+ and Ce 4+ , improved charge transfer and separation of electron-hole pairs generated on irradiation with simulated sunlight and proper amount of surface defects or oxygen vacancies on the BaTiO 3 /CeO 2 heterojunction photocatalysts.