Silver vanadates, visible-light-driven photocatalysts, have been synthesized using hydrothermal treatment
with the assistance of cetyltrimethylammonium bromide (CTAB). It is found that CTAB during the
hydrothermal synthesis significantly affects the morphology, crystal structure, optical absorbance, and
photocatalytic properties of silver vanadates. The pure silver vanadate oxides (SVO) consisted of mixed
structures of Ag4V2O7 and _-Ag3VO4, with _-Ag3VO4 as the major phase. As the amount of CTAB increased,
the crystal phase of CTAB-SVO sample approached Ag4V2O7. The band gaps for all CTAB-SVO samples
were found to be in the range of 2.29–2.43 eV. The reactivity of 0.5%CTAB-SVO (surface area, 6.51m2 g−1)
on isopropanol was 10 times higher than that of P25 (surface area, 49.04m2 g−1) under visible light
irradiation. The photocatalytic activity of CTAB-SVO sample decreased with an increase of Ag4V2O7. The
highest photocatalytic activity of 0.5%CTAB-SVO had the highest intensities of surface hydroxyl groups,
which were detected using the in-situ DRIFT technique. The density of surface hydroxyl groups, not the
crystalline structure, was confirmed as the key factor influencing the photocatalytic activity.
Relation:
Chemical Engineering Science/ v.65,issue1/ p148-152