Enhanced photocatalytic performance of cementitious material with TiO2@Ag modified fly ash micro-aggregates

A TiO2 photocatalyst is coated on the surface of a zeolite fly ash bead (ZFAB) to improve its dispersability and exposure degree in a cement system. The application of Ag particles in Ti0(2)/ZFAB modified cementitious materials is to further enhance the photocatalytic performance. Various Ag@Ti0(2)/ZFAB modified cementitious specimens with different Ag dosages are prepared and the characteristics and photocatalytic performance of the prepared samples are investigated. It is observed that the multi-level pore structure of ZFAB can improve the exposure degree of TiO2 in a cement system and is also useful to enhance the photocatalytic efficiency. With an increment of the amounts of Ag particles in the Ti0(2)/ZFAB modified cementitious samples, the photocatalytic activities increased first and then decreased. The optimal Ag@Ti0(2)/ZFAB modified cementitious sample reveals the maximum reaction rate constant for degrading benzene (9.91 x 10(-3) min(-1)), which is approximately 3 and 10 times higher than those of Ti0(2)/ZFAB and TiO2 modified samples, respectively. This suggests that suitable Ag particles coupled with a ZFAB carrier could effectively enhance the photocatalytic effects and use of TiO2 in a cement system. Thus, ZFAB as a carrier could provide a potential method for a high efficiency engineering application of TiO2 in the construction field. (C) 2017, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.