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TiO2 nanotube-based photocatalytic concrete paving block was prepared, and its mechanical properties, including compressive strength and abrasion resistance, as well as photocatalytic removal of NO, were investigated. Results indicate that the compressive strength and abrasion resistance of photocatalytic concrete paving block were obviously reinforced by TiO2 nanotubes compared with TiO2 nanoparticles, which might derive from the enhanced binding force between TiO2 nanotubes and calcium–silicate–hydrate (C–S–H) gel derived from the cement hydration. Moreover, the TiO2 nanotube-based photocatalytic concrete paving block shows the best photocatalytic removal of NO among the as-prepared samples, which might result from the enhanced adsorption property for NO gas over TiO2 nanotubes, and little change of NO conversion was found before and after polishing. Overall, TiO2 nanotubes not only contribute to the reinforcement of mechanical properties of the concrete block, but also dedicated to the enhancement of photocatalytic performance for NO purification.

The silver modified TiO2 photocatalysts were prepared by a rapid sol–gel method and used for the photocatalytic oxidization of different pollutants. The photocatalytic activity of as-prepared samples was evaluated by photo-degradation of organic methylene blue (MB), toluene, nitric oxide (NO) and phenol. The addition of Ag to TiO2 exhibits enhanced photocatalytic degradation of different pollutants due to the possibility of the prolonged lifetimes of photogenerated electron–hole pairs. As a result, we found that the photocatalytic activity of the Ag–TiO2 (1:25) powder was superior to that of pure TiO2 under both simulated sunlight and visible light irradiation. Furthermore, the Ag–TiO2 (1:25) also exhibits the highest photocatalytic activity for the degradation of toluene, NO and phenol. Under the similar conditions, the degradation efficiency of 80% for toluene and 92% for NO gas-phase pollutants was achieved after 100 min of irradiation.