Facet-, composition- and wavelength-dependent photocatalysis of Ag(2)MoO(4)

Faceted β-Ag(2)MoO(4) microcrystals are prepared by controlled nucleation and growth in diethylene glycol (DEG) or dimethylsulfoxide (DMSO). Both serve as solvents for the liquid-phase synthesis and surface-active agents for the formation of faceted microcrystals. Due to its reducing properties, truncated β-Ag(2)MoO(4)@Ag octahedra are obtained in DEG. The synthesis in DMSO allows avoiding the formation of elemental silver and results in β-Ag(2)MoO(4) cubes and cuboctahedra. Due to its band gap of 3.2 eV, photocatalytic activation of β-Ag(2)MoO(4) is only possible under UV-light. To enable β-Ag(2)MoO(4) for absorption of visible light, silver-coated β-Ag(2)MoO(4)@Ag and Ag(2)(Mo(0.95)Cr(0.05))O(4) with partial substitution of [MoO(4)](2−) by [CrO(4)](2−) were prepared, too. The photocatalytic activity of all the faceted microcrystals (truncated octahedra, cubes, cuboctahedra) and compositions (β-Ag(2)MoO(4), β-Ag(2)MoO(4)@Ag, β-Ag(2)(Mo(0.95)Cr(0.05))O(4)) is compared with regard to the photocatalytic decomposition of rhodamine B and the influence of the respective faceting, composition and wavelength.