BiOBr Precursor Solutions Modified Cement Paste: The Photocatalytic Performance and Effects

Abstract

The potential of photocatalysts modified cement-based materials in degrading environmental pollutants is evident in previous studies, but the application of photocatalytic cement-based materials still appears limited in actual practice due to the dispersion effect. This work seeks to prepare photocatalytic cement paste by mixing cement with BiOBr precursor solutions in terms of the improvement of dispersion efficiency, and additional hydrothermal conditions provided by autoclaved curing period are required to activate the photocatalytic activity of photocatalysts crystals. The presence of BiOBr precursor solutions results in an increase of RhB degradation rate of up to 45.4% and the NOx removal efficiency was up to 4.4%, and the formation of BiOBr photocatalysts crystals is the main reason for photocatalytic performance enhancement. The morphology of photocatalysts and the pore size distribution of cement paste also contribute to the photocatalytic activity enhancement by the exposed surface of photocatalysts, which are supported by the analyses of Scanning Electron Microscope and Mercury Intrusion Porosimetry results. A new mechanism is suggested to explain the synergistic role of crystals and microstructure on the enhancement of photocatalytic activity with the extension of autoclaved curing time. As supports for photocatalysts, the development changes of compressive strength of cement paste are also discussed.