Crystal structure and magnetic and photocatalytic properties of a new ternary rare-earth mixed chalcogenide, Dy4S4Te3

Abstract

The ternary dysprosium sulfur telluride Dy₄S₄Te₃ was synthesized by a facile solid-state route with boron as the reducing reagent. It crystallizes in the monoclinic space group C2/m with a = 6.720 (1), b = 13.748 (2), c = 6.715 (1) Å and β = 103.36 (1)°, belongs to the Ho₄S₄Te_2.68 structure type, and its 3-D structure features 2-D ladder-like (DyS)_n layers linked by Dy–Te1 and Dy–Te2 bonds with additional Te1–Te1 dumbbells. The (DyS)_n layers and the (DyQ)_n (Q = S, Se and Te) layers in other binary Dy–Q compounds are compared. Measurement of it magnetic susceptibility shows its paramagnetic behavior. The investigation of its optical properties indicates that it has an energy gap of 1.43 eV, which is also verified by the electronic band structure calculation via the Vienna ab initio simulation package (VASP). The photocatalytic behavior of the polycrystalline powder sample investigated by decomposing rhodamine B under halogen lamp irradiation indicates that its photocatalytic activity can be comparable to that of Degussa P25 TiO₂.