Phase stabilization and exposed {100} facet growth of a-Ag3VO4 photocatalyst: A low-temperature, template-free hydrothermal synthesis approach

The low-temperature phase stabilization, exposed {1 0 0} facet growth and solar light photocatalytic activity of alpha-Ag3VO4 microcrystals synthesized by a template-free hydrothermal procedure from AgNO3, NH4VO3 and ammonia were reported. By simply selecting a stoichiometric AgNO3/NH4VO3 molar ratio and a suitable amount of ammonia, pure alpha-Ag3VO4 powders were received readily at temperature as low as 100 ? while the competitive phase formation of the less photoactive Ag(4)V(2)O7 was inhibited completely. Especially, by increasing hydrothermal temperature from 100 to 160 ?, the crystallographic orientation growth of alpha-Ag3VO4 micro crystals along a-axis occurred and gradually diminished. For optimized sample, alpha-Ag3VO4 microcrystals were enclosed by exposed {1 0 0} facets, providing a significant enhancement in photocatalytic activity for methyl orange photodegradation under simulated solar light irradiation with respect to that of the random-oriented bulk sample. The role of ammonia on the low-temperature phase stabilization and exposed {1 0 0} facet growth of Ag3VO4 was also discussed.

Automated summary

The low-temperature phase stabilization, exposed {1 0 0} facet growth, and solar light photocatalytic activity of alpha-Ag3VO4 microcrystals were achieved through a template-free hydrothermal procedure. The addition of ammonia and the stoichiometric AgNO3/NH4VO3 molar ratio played important roles in controlling the crystal growth and inhibiting the formation of less photoactive phases.