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% degradation rate, making it suitable for absorbing visible light.

The paper reports the synthesise and characterization of a new isopolyvanadate compound, [Cs₃Na(VO₃)₄H₂O], which contains vanadim in the five oxidation state with tetrahedral coordination.  It forms metavanadate chains interconnected by caesium and sodium cations. The photocatalytic activity was tested by degrading methylen blue under visible light irradiation. The results showed decent activity attributed to the narrowed bandgap energy of 2.18 eV.