A new Bi-based visible-light-sensitive photocatalyst BiLa(1.4)Ca(0.6)O(4.2): crystal structure, optical property and photocatalytic activity

A new compound of BiLa(1.4)Ca(0.6)O(4.2) is synthesized through solid state reaction, where the Ca substitutes, in part, the La site in a stable BiLa(2)O(4.5) phase. The structure of the BiLa(1.4)Ca(0.6)O(4.2) crystallizes in space group R3mH with a hexagonal lattice constants of a = 3.893(1) Å, c = 9.891(1) Å. Its optical absorption edge is about 2.05 eV, which just spans the visible light region. The photocatalytic activity of the BiLa(1.4)Ca(0.6)O(4.2) powder to degradation of RhB under visible light irradiation is measured and improved more than 7 times by annealing in nitrogen ambient, indicating that annealing in nitrogen can effectively improve the photocatalytic activity by producing oxygen vacancy. Although the absolute photocatalytic activity obtained is low, there is great potential for enhancing the activity such as nanoscaling, doping, and coupling with other compounds.