Facile Synthesis of a WOx/CsyWO3 Heterostructured Composite as a Visible Light Photocatalyst

Optical absorption results revealed the WOx/CsyWO3 heterostructured composite exhibits a strong absorption tail in the Vis and NIR regions which could have important implications for its photoactivity. It can be used as photocatalyst. The photocatalytic performance of synthesized samples with different Cs/W molar ratios was evaluated by the photodegradation of RhB in aqueous solution under simulated solar light irradiation.

The results revealed that the photocatalytic activity of the WOx/CsyWO3 composite is much higher than those of pure tungsten bronze (CsxWO3, x = 0.32, and 0.5) and pure WO2.83 samples, where 90% RhB was degraded after 160 min irradiation. Also, the WOx/CsyWO3 composite exhibits excellent photocatalytic activity for the degradation of MO, MB, RhB, and MG aqueous solution under visible light irradiation.

cesium tungstate nanopowder applied for thermal insulation paper

It is proposed that the higher photocatalytic activity of the WOx/CsyWO3 composite could be attributed to the greater surface adsorption of dye molecules, intense light absorption in the visible and NIR regions, and photogenerated electron–hole separation.

 the photocatalytic activity of cesium tungsten oxide

The photocatalytic activity of synthesized samples was evaluated by the photodegradation of RhB in an aqueous solution as a model pollutant. The results revealed that the monoclinic/orthorhombic WO2.83/Cs0.069WO3 composite shows higher photocatalytic activity compared to the pure WO2.83 and pure tungsten bronze phase (CsxWO3, x = 0.32 and 0.50). Moreover, the WOx/CsyWO3 composite displays excellent photocatalytic activation under visible light irradiation, the photodegradation efficiencies of MO, MB, RhB, and MG molecules in the presence of photocatalyst after 160 min visible light irradiation (white light LED lamp) were 96%, 95%, 83%, and 98%, respectively.

schematic representation of band structure of WO2.83

The enhanced photocatalytic performance of WOx/CsyWO3 composite sample is attributed to the strong dye adsorption capability, intense light absorption, and effective separation of electron–hole pairs which could be attributed to the surface oxygen vacancies, polaron states below the conduction band, and the strong interaction between WO2.83 and Cs0.069WO3 phases, respectively.

SEM picture of cesium tungstate oxide