A facile preparation of Ag2O/P25 photocatalyst for selective reduction of nitrate

Ag2O/P25 and Ag/P25 catalysts were synthesized and applied in the photocatalytic reduction of nitrate with formic acid as a hole scavenger. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and transmission electron microscope (TEM) analysis demonstrate that Ag2O or Ag nanoparticles were well distributed on the surface of P25. Under UV irradiation, 5% Ag2O/P25 showed a fast rate (0.95 h(-1), 6.3 times of P25), a high conversion (97.2%, 3.63 times of P25) and a high N-2 selectivity (83.1%, 1.15 times of P25) for nitrate reduction. The improved separation of electron-hole pairs on Ag2O/P25 results in the high conversion of nitrate. Moreover, compared with the Ag/P25 catalyst, Ag2O/P25 exhibited a good reusability in nitrate reduction. The formed Ag-Ag2O structure [Ag(0) present on the surface of Ag2O] over P25 by partial photoreduction of deposited Ag2O contributed to the better stability of Ag2O/P25 in nitrate reduction. The present study provides a new sight into the use of Ag2O/P25 catalyst in the reduction of nitrate. (C) 2015 Elsevier B.V. All rights reserved.