Synthesis of Hollow B-SiO2@CaTiO3 Nanocomposites and Their Photocatalytic Performance in Ammonia Nitrogen Degradation

Abstract

Hollow B-SiO2@CaTiO3 nanocomposites were hydrothermally synthesized at a mild reaction temperature of 120 °C using calcium chloride and titanium (IV) isopropoxide as the starting materials and hollow B-SiO2 microspheres as the supports. CaTiO3 nanoparticles are anchored at the surfaces of hollow B-SiO2 microspheres through the formation of Ti–O–B and Ti–O–Si bonds. The interaction between the CaTiO3 nanoparticles and hollow B-SiO2 microspheres enlarged the band gap of CaTiO3 nanoparticles, giving a higher photocatalytic activity in ammonia nitrogen degradation at a lower catalyst loading and a wider range of ammonia nitrogen concentration. When the hollow B-SiO2@CaTiO3 (5wt%CaTiO3) photocatalyst was hydrothermally synthesized at 120 °C for 12 h, and the photocatalytic degradation reaction of ammonia nitrogen (50 mg L−1) in an aqueous solution was carried out under the simulated solar light irradiation at 25 °C for 4 h; the degradation extent of ammonium nitrogen reached 91%.