Photocatalytic activity of Portland cement loaded with 3D hierarchical Bi2WO6 microspheres under visible light

• 3D hierarchical Bi2WO6 microspheres were incorporated into Portland cement.
• 3D hierarchical structure remained on the surface of cement after hydration.
• Bi2WO6 photocatalytic cement can remove the pollutants under visible light efficiently.
• Catalysts cementitious materials are exposed to solar light widely.

In this work, photocatalytic cement was prepared by loading Bi2WO6 microspheres with Portland cement. 3D hierarchical Bi2WO6 microspheres were synthesized by self-assembly of 2D nanosheets and nanoplates firstly. Interestingly, Backscattered Electron (BSE) images showed Bi2WO6 hierarchical structure remained unchanged on the surface of hydration cement. The nanoplate and nanosheets which fell off from the Bi2WO6 microspheres distributed evenly on the surface of the hydration products. As to the inner structure of Bi2WO6/cement, a porous structure was observed and Bi2WO6 particles were located evenly in the pores. This result was in favor of enhancing photocatalytic performance and gas adsorption. The 15 wt% Bi2WO6/cement showed the highest photocatalytic activity, which can degrade the HCHO completely within 80 min under visible light. XRD and hydration heat results showed that Bi2WO6 hardly influences the hydration process. However, when the Bi2WO6 dosage was increased to beyond 15%, the hydration process was deterred and hydration heat decreased, which may influence the durability of the cement matrix.

3D hierarchical structure of Bi2WO6, the nanoplate and nanosheets facilitate the adsorption of organic gas. Interestingly, the hierarchical microsphere, the nanoplate and nanosheets did not aggregate together after stirring but distributed equably in the cement matrix.Figure optionsDownload as PowerPoint slide