Application of Supported TiO₂ in Carbonated Binding Material and Its Photocatalytic Performance

Although photocatalytic concrete can significantly contribute to the degradation of air pollutants and improving the sustainability levels, the complexity of ordinary cement system often caused the uncertain performance of mixed photocatalysts, which limited the real application of photocatalysts. Since the rapid carbonization hardening and relatively simple composition, γ-C2S carbonated binding material has gained considerable attention for its application in construction material. In this work, quartz sand-supported TiO2-C2S(γ) composites (TQSC) were prepared by mixing photocatalytic quartz sand with γ-C2S and mounting in γ-C2S matrix surface methods. The TiO2-coated quartz sand (TQS) was characterized by X-ray diffraction (XRD), quantitative X-ray fluorescence (XRF) and scanning electron microscopy (SEM). The photocatalytic performance and durability (washing resistance) of TQSC were also investigated by the degradation ability of NOx and rhodamine B (RhB). The results show that a uniform TiO2 layer on quartz sand was prepared, and the photocatalytic De-NOx (degradation of NOx) performance increased with increasing the mounted amounts of TiO2/quartz sand in γ-C2S carbonated matrix surface, but would decrease the photocatalytic durability. After water-washing, the De-NOx efficiencies of TQSC specimens decreased quickly at the beginning, which were adhering to the mounted amounts of TiO2/quartz sand, but would become stable after water-washing for 3600 s for all samples. The relatively high De-NOx stability and good self-cleaning effect of the water-washed TQSC-60% specimen can be considered a promising photocatalytic product for real applications.