Synthesis, Crystal Structure and Spectral Characterization of a New Caesium–Sodium-Isopolyvanadate: Photodegradation of Methylene Blue Dye

A new aqua-tricaesium-sodium polymetavanadate compound, [Cs3Na(VO3)4(H2O)] (1), was synthesized by reacting caesium chloride and sodium metavanadate at ambient pH. The structure was characterized and identified using single-crystal X-ray diffraction, Fourier-transform infrared spectroscopy, Raman spectroscopy, and energy dispersive X-ray analysis (EDS). Compound (1) crystallizes in an orthorhombic system with a Pnma space group, and cell parameters a = 11.6554(4), b = 8.3408(2), c = 16.1121(5). Vanadium has tetrahedral coordination connected to the next vanadium atom through an oxygen bridge. The infinite zigzag metavanadate chains formed by corner-sharing VO4 tetrahedral constitute a1D building block. The chains were laterally connected through Cs, Na, and H2O. This connectivity generates continuous 2D layers within the ab plane. The photocatalytic performance of (1) was evaluated by measuring the degradation of methylene blue under visible light. The results confirmed the efficiency of the photocatalytic activity because of the narrowed bandgap energy of 2.18 eV, and 85